Multicast Architecture

IP multicast is the transmission of data packets to multiple hosts through a common IP address. Arista switches support multicast transmissions through IGMP, IGMP Snooping, and PIM-SM. These topics describe the Arista multicast architecture.

Overview

Arista switches provide Layer 2 multicast filtering and Layer 3 routing features for applications requiring IP multicast services. The switches support over a thousand separate routed multicast sessions at wire speed without compromising other Layer 2/3 switching features. Arista switches support IGMP, IGMP snooping, PIM-SM, and MSDP to simplify and scale data center multicast deployments.

Supported Features

Feature support varies by platform; consult the release notes for multicast support information by platform.

Multicast and unicast use the same routing table. Unicast routes use TCAM resources, which may also impact the maximum number of multicast routes.

Features Not Supported

The multicast functions not supported by Arista switches include (*,*,G) forwarding or boundary routers, multicast MIBs, and router applications joining multicast groups.

Multicast Architecture Description

IP multicast is data transmission to a subset of all hosts through a single multicast group address. Multicast packets are delivered using best-effort reliability, similar to unicast packets. Senders use the multicast address as the destination address. Any host, regardless of group membership, can send to a group. However, only group members receive messages sent to a group address.

IP multicast addresses range from 224.0.0.0 to 239.255.255.255. Multicast routing protocol control traffic reserves the address range 224.0.0.0 to 224.0.0.255. The address 224.0.0.0 is never assigned to any group.

Multicast group membership is dynamic; a groups activity level and membership can vary over time. A host can also simultaneously belong to multiple multicast groups.

Multicast Architecture depicts the components that comprise the multicast architecture. The remainder of this section describes the multicast components depicted in the figure.

Figure 1. Multicast Architecture

Multicast Control Plane

The multicast control plane builds and maintains multicast distribution trees. It communicates changes in the multicast routing table to the MFIB for multicast forwarding.
  • Protocol Independent Multicast (PIM) builds and maintains multicast routing trees using Reverse Path Forwarding (RPF) on a unicast routing table.
  • Internet Group Management Protocol (IGMP) identifies multicast group members on subnets directly connected to the switch. Hosts manage multicast group membership with IGMP messages.
  • The switch maintains an mroute (multicast routing) table when running PIM to provide forwarding tables used to deliver multicast packets.
The mroute table stores the states of inbound and outbound interfaces for each source/group pair (S,G). The switch discards and forwards packets on the basis of this state information. Each table entry, referred to as an mroute, corresponds to a unique (S,G) and contains:
  • the multicast group address
  • the multicast source address (or * for all sources)
  • the inbound interface
  • a list of outbound interfaces

Multicast Routing Information Base (MRIB)

The MRIB is the channel between multicast control plane clients and the multicast forwarding plane. The show ip mroute command displays MRIB entries as (*, G), (S, G), and (*, G/m) multicast entries.

MRIB entries are based on source, group, and group masks. The entries are associated with a list of interfaces whose forwarding state is described with flags. MRIB communication is based on the state change of entry and interface flags. Flags are significant to MRIB clients but are not interpreted by the MRIB.

Multicast Forwarding Plane

The multicast forwarding plane consists of the Multicast Forwarding Information Base (MFIB), a forwarding engine that is independent of multicast routing protocols.

MFIB formats PIM and IGMP multicast routes for protocol-independent hardware packet forwarding and adds them to the hardware Multicast Expansion Table (MET) and the hardware FIB.

MFIB uses a core forwarding engine for interrupt-level (fast switching) and process-level (process switching) forwarding. MFIB fast-switches inbound multicast packets that match an MFIB forwarding entry and process-switches packets requiring a forwarding entry if a matching entry does not exist.

Hardware Dependent Forwarding and Fast Drop

In IP multicast protocols, each (S,G) and (*,G) route corresponds to an inbound Reverse Path Forwarding (RPF) interface. Packets arriving on non-RPF interfaces may require PIM processing, as performed by the CPU subsystem software.

By default, hardware sends all packets arriving on non-RPF interfaces to the CPU subsystem software. However, the CPU can be overwhelmed by non-RPF packets that do not require software processing. The CPU subsystem software prevents CPU overload by creating a fast-drop entry in hardware for inbound non-RPF packets not requiring PIM processing. Packets matching a fast-drop entry are bridged in the ingress VLAN but not sent to the software, avoiding CPU subsystem software overload. Fast-drop entry usage is critical in topologies with persistent RPF failures.

Protocol events, such as links going down or unicast routing table changes, can change the set of packets that can be fast dropped. Packets that were correctly fast dropped before a topology change may require forwarding to the CPU subsystem software after the change. The CPU subsystem software handles fast-drop entries that respond to protocol events so that PIM can process all necessary non-RPF packets.

Multicast Listener Discovery (MLD)

Networks use Multicast Listener Discovery (MLD) to control the flow of layer 3 IPv6 multicast traffic. Hosts request and maintain multicast group membership through MLD messages. Multicast routers use MLD to maintain a membership list of active multicast groups for each attached network.

With respect to each of its attached networks, a multicast router is either a querier or non-querier. Each physical network contains only one querier. A network with more than one multicast router designates the router with the lowest IP address as its querier.

In an MLD Report or Done message, the multicast address field holds a specific IPv6 multicast address to which the message sender is listening or is ceasing to listen, respectively.

MLDv2 Snooping

MLDv2 Snooping optimizes the transmission of multicast packets in Layer 2 by using Layer 3 information contained in MLDv2 and PIM packets. MLDv2 is the protocol used to manage the membership of hosts in multicast groups for IPv6.

RFC 3810 talks about MLDv2 functionality. MLDv2 is the IPv6 counterpart of IGMPv3. Beginning with eos Release 4.25.0F, MLDv2 snooping is supported on MLAG deployments.

Limitations

  • Extraneous “switch” interface should be ignored in show mld snooping counters and show mld snooping counters errors command outputs.
  • MLDv2 Snooping with EVPN is not supported.
  • On CCS-720XP, CCS-750, DCS-7050CX3, DCS-7050SX3, DCS-7050TX3 and DCS-7300X3 for MLDv2 snooping to be enabled on a vlan, IGMP snooping needs to be enabled on it too for IPv6 unknown multicast traffic to be forwarded over IPv4 and IPv6 mrouter ports, else such traffic would be flooded to entire vlan. Forwarding IPv6 unknown multicast traffic over only IPv6 mrouter ports is not supported on these platforms.

Configuring Multicast Listener Discovery

Enabling MLD

Use mld command to enable MLD on an interface. When the switch fills the multicast routing table, it only adds interfaces when the interface receives join messages from downstream devices or when the interface is directly connected to a member of the MLD group. By default, MLD is disabled on an interface.

Examples
  • This command enables MLD on the interface Ethernet 1.
    switch(config)# interface Ethernet 1
    switch(config-if-Et1)# mld
  • This command disables MLD on the interface Ethernet 1.
    switch(config)# interface Ethernet1
    switch(config-if-Et1)# no mld

Configuring MLD

An interface that runs MLD uses default protocol settings unless otherwise configured. The switch provides commands that alter startup query, last member query, and normal query settings.

MLD

The switch supports MLD versions 1 through 2. The mld command configures multicast routers on the configuration mode interface. Version 2 is the default MLD version.

Example

This command enables MLD on interface Ethernet 1.
switch(config)# interface Ethernet 1
switch(config-if-Et1)# mld
Startup Query

Membership queries are sent at an increased frequency immediately after an interface starts up to quickly establish the group state. Query count and query interval commands adjust the period between membership queries for a specified number of messages.

The mld startup-query-interval command specifies the interval between membership queries that an interface sends immediately after it starts up. The mld startup-query-count command specifies the number of queries that the switches sends from the interface at the startup interval rate.

Examples
  • This command configures the startup query count of 4 on interface Ethernet1.
    switch(config)# interface Ethernet1
    switch(config-if-Et1)# mld startup-query-count 4
  • This command configures the startup query interval of 100 seconds on interface Ethernet1.
    switch(config)# interface Ethernet1
    switch(config-if-Et1)# mld startup-query-interval 100
Membership Queries

The router with the lowest IP address on a subnet sends membership queries as the MLD querier. When a membership query is received from a source with a lower IP address, the router resets its query response timer. Upon timer expiry, the router begins sending membership queries. If the router subsequently receives a membership query originating from a lower IP address, it stops sending membership queries and resets the query response timer.

The mld query-interval command configures the frequency at which the active interface, as an MLD querier, sends membership query messages.

The mld query-response-interval command configures the time that a host has to respond to a membership query.

Examples
  • This command configures the query interval of 30 seconds on interface Ethernet1.
    switch(config)# interface Ethernet1
    switch(config-if-Et1)# mld query-interval 30
  • This command configures the query response interval of 30 seconds on interface Ethernet1.
    switch(config)# interface Ethernet1
    switch(config-if-Et1)# mld query-response-interval 30
Last Member Query

When the querier receives an MLD leave message, it verifies the group has no remaining hosts by sending a set of group-specific queries at a specified interval. If the querier does not receive a response to the queries, it removes the group state and discontinues multicast transmissions.

The mld last-listener-query-count command specifies the number of query messages the router sends in response to a group-specific or group-source-specific leave message.

The mld last-listener-query-interval command configures the transmission interval for sending group-specific or group-source-specific query messages to the active interface.

Examples
  • This command configures the last listener query count to 3 on interface Ethernet1.
    switch(config)# interface Ethernet1
    switch(config-if-Et1)# mld last-listener-query-count 3
  • This command configures the last listener query interval to 2 seconds on interface Ethernet1.
    switch(config)# interface Ethernet1
    switch(config-if-Et1)# mld last-listener-query-interval 2
Static Groups

The mld static-group command configures the configuration mode interface as a static member of the multicast group at the specified address. The router forwards multicast group packets through the interface without otherwise appearing or acting as a group member. No interface is a static member of a multicast group by default.

Example

This command configures static groups on interface Ethernet1.
switch(config)# interface Ethernet1
switch(config-if-Et1)# mld static-group ff30::1 a::1

MLDv2 Snooping Configuration

Enabling or Disabling MLDv2 Snooping

You can configure MLDv2 snooping globally and per VLAN. A configuration mode is available for MLD related snooping commands in the global configuration mode.

Example
switch(config)# mld snooping
switch(config-mld-snooping)# disabled
switch(config-mld-snooping)# vlan 1-100
switch(config-mld-snooping)# vlan 101
switch(config-mld-snooping-vlan-101)# disabled
Items to consider:
  • You must explicitly configure VLANs inside the mld-snooping configuration mode to enable snooping for those VLANs.
  • Use the global disabled to disable the mld-snooping for all VLANs. disabled is not configured by default.
  • Snooping can be explicitly disabled for a given VLAN. This is useful once there is configuration within the VLAN. disabled is not configured by default.
  • Snooping cannot be explicitly enabled for a given VLAN if it is disabled globally.
  • Beginning with the eos Release 4.25.0F, it allows the configuration of MLDvs snooping on PIM non DR (Designated Router) VLANs.

Static Groups and Multicast Router

To configure static groups, refer to the following commands:

switch(config)# mld snooping
switch(config-mld-snooping)# vlan 100
switch(config-mld-snooping-vlan-100)# member ipv6-group-addr interface intfs

To configure a static multicast router, refer to the following commands:

switch(config)# mld snooping
switch(config-mld-snooping)# vlan 100
switch(config-mld-snooping-vlan-100)# multicast-router interface intfs

In the examples above, intfs can be a group of similar interfaces (for example, Ethernet1-5,8 or port-channel 1-5,8).

Displaying MLDv2 Snooping Status

The following show commands display the MLD snooping status of the switch:
  • switch# show mld snooping
       Global MLD Snooping configuration:
    -------------------------------------------
    MLD snooping                   : Enabled
    Robustness variable            : 2
    
    VLAN 1 :
    ----------
    MLD snooping                   : Disabled
    MLD max group limit            : No limit set
    Recent attempt to exceed limit : No
    MLD snooping pruning active    : False
    Flooding traffic to VLAN       : True
    VLAN 100 :
    ----------
    MLD snooping                   : Enabled
    MLD max group limit            : No limit set
    Recent attempt to exceed limit : No
    MLD snooping pruning active    : True
    Flooding traffic to VLAN       : False
  • switch# show mld snooping
       Global MLD Snooping configuration:
    -------------------------------------------
    MLD snooping                   : Enabled
    Robustness variable            : 2
    
    VLAN 1 :
    ----------
    MLD snooping                   : Disabled
    MLD max group limit            : No limit set
    Recent attempt to exceed limit : No
    MLD snooping pruning active    : False
    Flooding traffic to VLAN       : True
    VLAN 100 :
    ----------
    MLD snooping                   : Enabled
    MLD max group limit            : No limit set
    Recent attempt to exceed limit : No
    MLD snooping pruning active    : True
    Flooding traffic to VLAN       : False
  • Use the show mld snooping groups command to display MLDv2 snooping by group.

    switch# show mld snooping groups
    IGMP Snooping Group Membership
    EX : Filter mode Exclude
    IN : Filter mode Include
    IR : Ingress Replication
    VLAN  Group            Members
    ----  ---------------  ------------------------
    100   ff05::2          Cpu, Et4
    100   ff08::11         Et1
    100   ff08::21         Et2
    100   ff08::31         Et3
    100   *                Et3, Et4
  • Use the show mld snooping groups detail command to display detailed MLDv2 snooping information.

    switch(config-mld-snooping-vlan-100)# show mld snooping groups detail
    IGMP Snooping Group Membership
    EX : Filter mode Exclude
    IN : Filter mode Include
    IR : Ingress Replication
    VLAN  Group            Source     Mode  Uptime       Members
    ----  ---------------  ---------  ----  -----------  ----------
    100   ff05::2          *           -     0d00h13m20   Cpu, Et4
    100   ff08::11         *           -     0d00h13m17   Et1
    100   ff08::21         1::1        IN    0d00h13m20   Et2
    100   ff08::31         2::1        EX    0d00h01m31   Et3
    100   *                *            -     -           Et3, Et4
    The show mld snooping groups output can be further filtered to output just the
    • local groups, that is groups learned locally using the show mld snooping groups local command.

    • user groups, that is groups configured by user.

    • mlag groups, that is groups learned from the MPLAG peer.
  • switch# show mld snooping mrouter
    Vlan    Interface-ports
    -------------------------------------------
    100     Et3(dynamic), Et4(static)
  • switch# show mld snooping mrouter detail
    Vlan   Intf      Address           FirstHeard   LastHeard    Expires  Type
    ---------------------------------------------------------------------------------
    100    Et3       fe80::200:3ff:fe01:0 0d00h24m30  0d00h00m08  00h00m17 querier
    100    Et4       fe80::200:3ff:fe03:0 0d00h24m10  0d00h00m08  00h01m37 pim
    100    Et2       0.0.0.0           -           -           -           static
  • switch# show mld snooping mrouter vlan 100
    Vlan    Interface-ports
    ------------------------------------------------------------
    100     Et2(static), Et3(dynamic), Et4(dynamic)
  • switch# show mld snooping querier
    Vlan  IP Address               Version  Port
    --------------------------------------------
    100   fe80::200:3ff:fe01:0     v2       Et3
    
  • switch# show mld snooping querier vlan 100
    IP Address           : fe80::200:3ff:fe01:0
    MLD Version          : v2
    Port                 : Et3
    Max response time    : 10.0
  • switch# show mld snooping counters
                    Input                 |    Output
    Port   Queries Reports  Others  Errors|Queries Reports  Others
    --------------------------------------------------------------
    Cpu          1     153       0       0     154       6      51
    Et1          0     153       0       0     156       0      51
    Et2          0     153       0       0     156     110      51
    Et3        154       1       0       0       1     610      51
    Et4          0     152      51       0     155     453       0
    switch       0       0       0       0       0       0       0
  • switch# show mld snooping counters errors
               Packet       Packet  Bad IP    Unknown      Bad PIM   Bad ICMP  Bad MLD   Bad MLD
    Port       Too Short    Not IP  Checksum  IP Protocol  Checksum  Checksum  Query     Report
    ---------------------------------------------------------------------------------------------
    Cpu                0         0         0            0         0         0         0         0
    Et1                0         0         0            0         0         0         0         0
    Et2                0         0         0            0         0         0         0         0
    Et3                0         0         0            0         0         0         0         0
    Et4                0         0         0            0         0         0         0         0
    switch             0         0         0            0         0         0         0         0

Multicast Route Counters

Multicast Route Counters provides per multicast route ingress packet and byte counters for multicast routed packets.

Configuration

To enable multicast route ingress packet and byte counters use the following command:
switch(config)# hardware counter feature multicast ipv4
To disable multicast route ingress packet and byte counters use the following command:
switch(config)# no hardware counter feature multicast ipv4
On DCS-7020R, DCS-7280R/R2 and 7500R/R2 platforms, create and apply user defined TCAM profile with multicast counter feature db enabled. This example reates a profile copying it from the default, then modifying the profile.
switch(config)# hardware tcam
switch(config-hw-tcam)# profile <profileName> copy default
switch(config-hw-tcam-profileName)# feature counter multicast ipv4
switch(config-hw-tcam-profileName-feature-counter-multicast-ipv4))# exit
switch(config-hw-tcam-profileName)# no feature mirror ip
switch(config-hw-tcam-profileName)# exit
switch(config-hw-tcam)# system profile <profileName>

Show Commands

Use the show ip mfib counters command to display per multicast route ingress packet and byte counters:

switch# show ip mfib 225.1.2.1 10.46.1.2 counters 
Activity poll time: 60 seconds
   225.1.2.1 10.46.1.2
      Byte: 1200200
      Packet: 12002
      Ethernet46 (iif)
      Ethernet47
      Activity 0:02:52 ago
switch#
switch# show ip mfib counters
Activity poll time: 60 seconds
   225.1.1.1 0.0.0.0/0
      Byte: 234100
      Packet: 2341
      1 (rpaIndex)
      Ethernet21
      Ethernet23
      Activity 1:00:52 ago
   225.1.2.1 10.46.1.2
      Byte: 1200200
      Packet: 12002
      Ethernet46 (iif)
      Ethernet47
      Activity 0:02:52 ago
   224.0.0.0/4 10.45.1.0/24
      Byte: N/A
      Packet: N/A
      Ethernet45 (iif)
      Cpu
      Activity 0:02:04 ago
switch#

To clear all counters including per multicast route ingress counters, use the clear counters command.

switch# clear counters

To clear per multicast route ingress counters or clear counters for a particular multicast route, use the clear ip multicast counters command.

switch# clear ip multicast <vrf [vrf-name]> counters <group_addr> <source_addr>

Limitations

This feature contains the following limitations:
  • Counters are not supported on fastdrop multicast routes.
  • For Pim sparse mode, counters are supported only on (Source_addr, Group_addr) multicast routes.
  • Counting is supported for IPv4 multicast packets only.

Multicast (S,G) Counters

The Multicast Route Counters count the packets and bytes per group, source, and VRF. Every multicast route is counted when the Multicast (S,G) counters is enabled, and if there are sufficient hardware counter resources available. Since the number of hardware counter resources is limited, selected multicast routes can be prioritized to provide them the needed hardware counter resources over the non-priority multicast routes in case of resource contention.

Priority multicast routes can be configured if:

  • Hardware counter resources are available:
    • The priority multicast routes do not affect the existing non-priority multicast route counters.
  • In case there are insufficient hardware counter resources:
    • If there are non-priority multicast routes, one non-priority multicast route counter resource will be freed, which results in losing the counters for the non-priority multicast route, and the priority multicast route will be programmed, meanwhile the non-priority multicast route will be pending to be programmed until there are hardware counter resources available.
    • If there are only priority multicast groups, the newly configured priority multicast groups will wait till the resources are freed by existing priority groups.

Configuring Multicast (S,G) Counters

  • The multicast (S, G) counters feature is configured using the following command in the configuration mode:

    hardware counter feature multicast [ipv4 | ipv6]

    The hardware counter feature multicast command enables counting for all groups as non-priority groups unless the groups that require priority treatment have been configured under router multicast as described in the next paragraph. Use the no form of the command to disable the multicast (S, G) counters on a switch.
  • Certain multicast routes can be configured as priority multicast routes for counting purposes, and they will be counted with higher priority. In case of running out of hardware counter resources, this could result in deleting the existing multicast (S, G) counters. The following configuration shows how the IPv6 version is configured, it’s similar to IPv4. Use the no counters command to disable the priority routes.
    switch(config)# router multicast	
    switch(config-router-multicast)# ipv6
    switch(config-router-multicast-ipv6)# counters
    switch(config-router-multicast-ipv6)# counters ff08::e101:101 2002::a01:101
    Of the above configuration steps, the following command is required before configuring the specific multicast routes:
    switch(config-router-multicast-ipv6)#
    Otherwise the system prompts the following error:
    ! 'counters' not configured, packet will not be counted
  • Clear counters:

    clear ipv6 multicast [vrf [vrf-name]] counters group source

    The above CLI command can either clear the counters for all multicast routes or the specific (vrf, group, source). The default VRF will be used if it is not specified. All the IPv6 counters are cleared if no group and source are specified. The IPv4 version of the command is:

    clear ip multicast [vrf [vrf-name]] counters group source

    The below command clears the counters of all multicast routes along with all other counters.
    switch# clear counters

Multicast (S,G) Counters Show Commands

  • The hardware counter resources are allocated if the Multicast (S,G) Counters is configured. The configuration state is shown as the following: Mcast is listed in the Feature ID field and the Counters column indicates the total number of hardware counter resources assigned to the Multicast (S,G) Counters:
    switch# show platform trident flexcounters summary 
    Feature ID   Type        Request ID   Pool ID    Start Index   Counters      
    ------------------------------------------------------------------------      
    Mcast        ingress     0            0          1             8191   
  • The current counter resource allocation for each multicast route is shown using the following CLI command.The Pool ID column indicates which pool is used, and the Base Counter Index indicates the entry index in that pool.
    switch# show platform trident flexcounters multicast summary                            
    Group           Source         VRF  VLAN  Counter Index  Pool ID  Offset Mode Base Counter Index 
    --------------- -------------- ---- ----- -------------- -------- ----------- ------------------ 
    ff08::e101:101  2002::a01:105  0    2570  1              0        0           1
    225.1.1.1       10.1.1.5       0    2571  2              0        0           2
  • The raw counter value of the each multicast route is shown using the following command. The cntTbl reflects the hardware table, the counters are copied from ctnTbl to snapTbl when the clear counter command is issued. The difference between ctnTbl and snapTbl is the current counter.
    switch# show platform trident flexcounters multicast values 
    Group           Source       VRF VLAN Counter Index  Offset Bytes (cntTbl)  Bytes (snapTbl) Pkts (cntTbl) Pkts (snapTbl) 
    -------------- ------------- --- ---- -------------- ---------------------  --------------- ------------- -------------- 
    ff08::e101:101 2002::a01:105 0   2570 1              6600                    0              100           0
    225.1.1.1      10.1.1.5      0   2571 2              8800                    0              100           0
  • The multicast (S,G) counters is shown using the following CLI command. In the following example Byte and Packet are the counters:
    switch# show multicast fib ipv6 <vrf [vrf-name]> <group> <source> counters
    Activity poll time: 60 seconds
    ff08::e101:101 2002::a01:101
        Byte: 66
        Packet: 1
        Vlan2780 (iif)
        Ethernet6/4
        Vlan2899
    
    switch# show multicast fib ipv4 <vrf [vrf-name]> <group> <source> counters
    Activity poll time: 60 seconds
    255.1.1.1 10.1.1.5
        Byte: 66
        Packet: 1
        Vlan2781 (iif)
        Ethernet8/4
        Vlan2999

Limitations

The number of counters for which the hardware counters can be enabled simultaneously will be limited by the availability of counter hardware resources in the system.

When the configured hardware features exceed the available counter resources not all counters for all features will be available, the following CLI command shows the current allocation of the hardware resources:
switch# show platform trident flexcounters summary 
Feature ID   Type       Request ID   Pool ID   Start Index   Counters      
---------------------------------------------------------------------      
Mcast        ingress    0            0         1             8191 

Static IP Mroute

The Static IP Multicast route (or Static Mroute) interface overrides the interface that is ordinarily selected from the matching route in the unicast routing table, providing a means for breaking dependency on the unicast topology for the multicast topology. Let us assume that, PIM routers in a multicast network sends PIM joins towards a source to receive traffic from that source. The interface on which to send a PIM join is determined by looking up the unicast routing table for the source address. This interface is the upstream or RPF interface for that source. When traffic is received from that source, it is ensured it is received on the RPF interface for that source. This mechanism causes multicast traffic to take the same path through a network as unicast traffic would. In some cases, it is desirable to have the multicast traffic take a different path than the unicast traffic. For example, to avoid a slow firewall required for unicast traffic but not for multicast traffic or to receive multicast across a low latency, low bandwidth microwave link while unicast traverses a higher latency, higher bandwidth fiber path.

To overcome this situation, a static IP multicast route (or Static Mroute) command ip mroute command is introduced. The ip mroute command specifies a candidate for the RPF interface of any (S,G) multicast route where the source falls within the given source/mask. This interface potentially overrides the interface that would ordinarily have been selected from the matching route in the unicast routing table. This command, therefore, provides a means of breaking the dependence of the multicast topology on the unicast topology. The method of selecting the RPF interface for an (S,G) route is described next.

Example

This command configures a Static IP mroute for a source 1.1.1.1/32 with an administrative distance 20 on interface ethernet 2/1.
switch(config)# ip mroute 1.1.1.1/32 ethernet 2/1 20

Selecting Static Mroute

The Static Mroute is selected based the following parameters:
  • Longest Match
  • Administrative Distance
  • Interface Status

Longest Match

When a given source matches multiple static Mroutes in the MRIB, the longest match will be selected. The order in which the static Mroutes were configured will not be a factor.

Example

If the following static mroutes were configured in order:
ip mroute 0.0.0.0/0 Ethernet1
ip mroute 192.168.0.0/16 Ethernet2
ip mroute 192.168.1.0/24 Ethernet3
For an (S,G) route where S = 192.168.1.1, the third static mroute listed above would be selected since it is the most specific route to the source. The RPF interface would therefore be Ethernet3. The table below shows the selected RPF interface for three different sources based on the configuration above:
Source RPF Interface
192.168.1.1 Ethernet 3
192.168.1.2 Ethernet 3
192.168.2.1 Ethernet 2
10.0.0.1 Ethernet 1

Administrative Distance

User is allowed to specify an administrative distance with each static Mroute. While selecting a Static Mroute for a source, if multiple Static Mroute exist in the MRIB with the same source/mask, then, the one with the lowest Admin distance is selected. The default administrative distance for a Static Mroute is 1.

Interface Status

For a Static Mroute to be considered for selection, the specified interface must be UP and PIM must be enabled on it.

Selecting RPF interface

Static Mroutes are BGP IP Multicast (SAFI 2) learned routes. These routes are stored in the Multicast Routing Information Base (MRIB), a separate routing table. The RPF interface is selected for a source as follows:

initially, a source route is looked up in the MRIB. If the MRIB lookup yields a route, that route is used for selecting the RPF interface. Therefore, any configured Static Mroutes matching the source wins the selection process over a 'Connected' route to the source. For a static mroute to be considered for selection, the specified interface must be up and PIM must be enabled on it. By default, Static Mroute have an Admin distance of 1. If multiple Static Mroutes exist with equal longest prefix match, the mroute with the lowest Admin distance will win. Admin distance is not be used to compare selection between unicast RIB and MRIB routes. Successful Static Mroute looked up in the MRIB are always chosen over unicast RIB lookups.

If MRIB lookup does not yield a route, then the unicast RIB is looked up for a route to select the RPF interface. If the selected route has ECMP, one of the corresponding paths is selected as RPF neighbor.

Note: The path to choose RPF neighbor is selected based on the hashing scheme; and protocols specified for valid paths, multi-path configuration, directly connected sources, and assert winners.

Example

Let us assume that the Static Mroute is configured, and for this example let us consider that the default Admin distance for connected routes is 0, 1 for static routes, and 110 for OSPF routes.
ip mroute 172.16.0.0/16 Ethernet1
ip mroute 192.168.0.0/16 Ethernet2
ip mroute 192.168.1.0/24 Ethernet3
ip mroute 192.168.1.0/24 Ethernet4 255
ip mroute 192.168.1.3/32 Ethernet5 255
ip mroute 200.10.0.0/16 Ethernet5
ip mroute 200.11.0.32/16 Ethernet5
So the MRIB table contains the following:
Prefix Interface Admin Distance
172.16.0.0/16 Ethernet 1 1
192.168.0.0/16 Ethernet 2 1
192.168.1.0/24 Ethernet 3 1
192.168.1.0/24 Ethernet 4 255
192.168.1.3/32 Ethernet 5 255
200.10.0.0/16 Ethernet 5 1
200.11.0.1/32 Ethernet 5 1
And let us assume the unicast RIB table contains the following:
Prefix Interface Protocol Admin Distance
10.0.0.0/24 Ethernet 6 OSPF 110
172.16.1.0/24 Ethernet 7 OSPF 110
192.168.0.0/16 Ethernet 8 OSPF 110
192.168.1.0/24 Ethernet 9 Static 1
192.168.1.3/32 Ethernet 10 OSPF 110
200.10.0.0/16 Ethernet 11 Connected 0
The table below shows the RPF interface selections for a set of sources along with which Static Mroute was chosen, which unicast RIB route was chosen, which was the eventual winner, and the reasoning behind the selection.
Source Static Mroute Unicast Route Winner RPF Interface Reasoning
10.0.0.1 - 1 Unicast Route Ethernet 6
  • Only the unicast Rib yields a route to the source so it wins
200.11.0.1 7 - Static Mroute Ethernet 5
  • Only the MRIB yields a route to the source so it wins
192.168.1.3 5 5 Unicast Route Ethernet 10
  • In the MRIB (5) is the longest match
  • While comparing the static mroute and the unicast route, the unicast route is the winner because it has a lower Admin distance
192.168.2.1 2 3 Static Mroute Ethernet 2
  • In the MRIB (2) is the longest match
  • While comparing the static mroute and the unicast route, the static Mroute is the winner because it has a lower Admin distance
192.168.1.1 3 4 Static Mroute Ethernet 3
  • In the MRIB both (3) and (4) are the longest match but (3) has the lower Admin distance
  • While comparing the static mroute and the unicast route, the static mroute is the winner even though both have the same distance

Static Multicast

Static Multicast enables to configure multicast routes statically on any Arista switches and even at per VRF granularity. However, static multicast routes do not, at this point, perform any VRF validation for the interfaces involved in the route, which can cause some possibility of route leakage. The Static Multicast co-exists with PIM-SM and PIM-BIDIR protocols which are dynamic variants of programming multicast routes. However, choose the appropriate route selection method before the static routes are programmed to obtain the best results.

Static multicast routes compete with the routes provided by PIM-SM and PIM-BIDIR mainly because this static variant, allows the operator to configure a PIM-SM-like or PIM-BIDIR-like route among other routes. The route chosen depends upon setting up the priority on the route.

At present, PIM-SM/PIM-BIDIR installs routes with a priority value of 0 (zero) while static route installs routes with a priority of 255, by default.

The priorities of PIM-SM and PIM-BIDIR are subject to future change. Higher priority wins in case of conflicts while programming the hardware. Conflicts here imply the same route present as static multicast route and in PIM-SM/PIM-BIDIR. It concludes that, by default, static multicast routes will always be the winner.

Configuring Multicast

Enabling IPv4 Multicast Routing

Enabling IPv4 multicast routing allows the switch to forward multicast packets. The routing command enables multicast routing. When multicast routing is enabled, running-config contains a routing statement.

Example

These commands enable IPv4 multicast routing on the switch.
switch(config)# router multicast
switch(config-router-multicast)# ipv4
switch(config-router-multicast-ipv4)# routing

Enabling IPv6 Multicast Routing

Enabling IPv6 Multicast routing allows the switch to distribute IPv6 datagrams to one or more recipients. IPv6 PIM builds and maintains Multicast routing using Reverse Path Forwarding (RPF) based on unicast routing table. IPv6 PIM is protocol-independent and can use routing tables consisting of OSPFv3, IPv6 BGP or static routes, for RPF lookup. MLD is used to discover Multicast hosts and maintain group membership on directly attached link. This feature is supported on 7280R and 7500R. Source-specific multicast (SSM) is currently supported on L3 routed port.

PIM Sparse Mode

In PIM-SM, each host (sender and/or receiver) is associated with a Designated Router (DR) which acts for all directly connected hosts in PIM-SM transactions. Upon receiving of MLD report from host or PIM join from downstream PIM neighbor, (S,G) route is created or programmed and router sends a PIM join to upstream PIM neighbor with shortest path to the source.

Configuring IPv6 Multicast Routing

The following steps are to configure IPv6 multicast routing on the switch.

  1. Enabling IPv6 multicast-routing. By default, multicast-routing is disabled on switch. The following commands are used to enable IPv6 multicast-routing.

    Example

    switch(config)# router multicast
    switch(config-router-multicast)# ipv6
    switch(config-router-multicast-ipv6)# routing
  2. Enabling IPv6 PIM Sparse Mode.

    By default, IPv6 PIM is disabled on an interface. The pim ipv6 sparse-mode command enables an interface to participate in IPv6 multicast-routing domain.

    Example

    switch(config)# interface ethernet 15/1
    switch(config-if-Et15/1)# pim ipv6 sparse-mode
    Note: SVI is not supported.
  3. Enabling MLD.

    By default, MLD is disabled on an interface. Enabling MLD is needed only on the interface that is connected to the MLD host which would like to receive IPv6 multicast traffic.

    Example
    switch(config)# interface ethernet 15/1
    switch(config-if-Et15/1)# mld

Multicast-Routing Configuration Example

router multicast
   ipv6
      Routing
interface Ethernet15/1
   no switchport
   ipv6 enable
   ipv6 address 40:1::3/64
   mld
   pim ipv6 sparse-mode

Displaying IPv6 Multicast Routing Information

  • The show mld membership command displays the MLD group membership table as shown.
    switch# show mld membership
    Interface            Group              Source                                   
    Filter Mode
    --------------------------------------------------
    Ethernet2/1.1        ff33::1:0:0:1      101:1::2                                 
    include
    Ethernet2/1.1        ff33::1:0:0:2      101:1::2                                 
    include
    Ethernet2/1.1        ff33::1:0:0:3      101:1::2                                 
    include
    Ethernet2/1.1        ff33::1:0:0:4      101:1::2                                 
    include
    Ethernet2/1.1        ff33::1:0:0:5      101:1::2                                 
    include
    Ethernet2/1.1        ff33::1:0:0:6      101:1::2                                 
    include
    Ethernet2/1.1        ff33::1:0:0:7      101:1::2                                 
    include
    Ethernet2/1.1        ff33::1:0:0:8      101:1::2                                 
    include
    Ethernet2/1.1        ff33::1:0:0:9      101:1::2                                 
    include
    Ethernet2/1.1        ff33::1:0:0:a      101:1::2                                 
    include
    Ethernet2/1.1        ff33::1:0:0:b      101:1::2                                 
    include
  • The show pim ipv6 sparse-mode route command displays the PIM Sparse Mode Multicast Routing table as shown.
    switch# show pim ipv6 sparse-mode route
    PIM Sparse Mode Multicast Routing Table
    Flags: E - Entry forwarding on the RPT, J - Joining to the SPT
        R - RPT bit is set, S - SPT bit is set, L - Source is attached
        W - Wildcard entry, X - External component interest
        I - SG Include Join alert rcvd, P - (*,G) Programmed in hardware
        H - Joining SPT due to policy, D - Joining SPT due to protocol
        Z - Entry marked for deletion, C - Learned from a DR via a register
        A - Learned via Anycast RP Router, M - Learned via MSDP
        N - May notify MSDP, K - Keepalive timer not running
        T - switching Incoming Interface, B - Learned via Border Router
    RPF route: U - From unicast routing table
               M - From multicast routing table
    ff33::1:0:0:1
      101:1::2, 2:03:00, flags: S
        Incoming interface: Ethernet11/1
        RPF route: [U] 101:1::/64 [110/1] via fe80::464c:a8ff:feb7:39e9
        Outgoing interface list:
          Ethernet6/1.1
          Ethernet4/1.1
          Ethernet7/1.1
          Ethernet9/1.1
          Ethernet8/1.1
          Ethernet2/1.1
          Ethernet5/1.1
          Ethernet3/1.1
    
  • The show multicast fib ipv6 command displays the Multicast Forwarding Information Base (MFIB) table.
    switch# show mfib ipv6
    Activity poll time: 60 seconds
      ff33::1:0:0:1 101:1::2
        Ethernet11/1 (iif)
        Ethernet9/1.1
        Ethernet2/1.1
        Ethernet3/1.1
        Ethernet6/1.1
        Ethernet5/1.1
        Ethernet8/1.1
        Ethernet7/1.1
        Ethernet4/1.1
          Activity 0:00:35 ago
  • The show platform fap mroute ipv6 command displays the Platform Hardware Forwarding table.
    switch# show platform fap mroute ipv6
    Jericho0 Multicast Routes:
    --------------------------
    Location    GroupId    Group                          Source                            
    IIF         McId       OIF
    FLP/TT      FLP/TT     TT                             FLP                                 
    FLP         FLP        FLP
    --------------------------------------------------------------------
    4096/2048   1/1       ff33::1:0:0:23/128               101:1::2/128                    
    Vlan1357 21504     Vlan1044(Et7/1) Vlan1123(Et9/1)         
                                                                                                                                                                 
    Vlan1200(Et8/1) Vlan1223(Et2/1)
                                                                                                                                                                 
    Vlan1226(Et5/1) Vlan1232(Et3/1)
                                                                                                                                                                 
    Vlan1307(Et6/1) Vlan1337(Et4/1)

Multicast Boundary Configuration

The multicast boundary specifies subnets where source traffic entering an interface is filtered to prevent the creation of mroute states on the interface. The interface is not included in the Outgoing Interface List (OIL). Multicast PIM, IGMP and other multicast data cannot cross the boundary, facilitating the use of a multicast group address in multiple administrative domains.

In addition, an interface with a boundary ACL will filter any joins (RX or TX) for groups that are not allowed by the ACL. This also applies to multicast boundary ACLs with the s option.

The ip multicast boundary command configures the multicast boundary. The multicast boundary can be specified through multiple IPv4 subnets or one standard IPv4 ACL.

In an ACL method, the multicast subnets are allowed only from the permit entries of the ACL and rest is either denied or filtered. Whereas, in a non-ACL method the statements configure subnets that are only denied or filtered.

Examples
  • These commands configure the multicast address of 229.43.23.0/24 as a multicast boundary where source traffic is restricted from interface vlan 300.
    switch(config)# interface vlan 300
    switch(config-if-vl300)# ip multicast boundary 229.43.23.0/24
    switch(config-if-vl300)#
  • These commands create a standard ACL, then implement the ACL in an ip multicast boundary command to allow multicast for subnet (224.0.0.0/4) and create a multicast boundary for all remaining subnets by denying them.
    switch(config)# ip access-list standard mbac1
    switch(config-std-acl-mbac1)# 10 deny 225.123.0.0/16
    switch(config-std-acl-mbac1)# 20 deny 239.120.10.0/24
    switch(config-std-acl-mbac1)# 30 permit 224.0.0.0/4
    switch(config-std-acl-mbac1)# exit
    switch(config)# interface vlan 200
    switch(config-if-Vl200)# ip multicast boundary mbac1
    switch(config-if-Vl200)# exit
    switch(config)#

Multicast multipath router-ID (IPv4)

The multipath deterministic command with the router-ID allows downstream PIM neighbors to direct traffic for a group or source-group to be routed through only the specified upstream PIM neighbor for all downstream PIM neighbors with the same ECMP routes. Traffic is load balanced by group or source-group across upstream PIM neighbors as in the default multipath mode.

Multipath router-ID uses the Interface Identifier (from the Hello Option for PIM) to give PIM-enabled devices a globally unique router ID for each of their PIM neighbors.

The following configures the switch to use the router_ID.

switch(config)# router multicast 
switch(config-router-multicast)# ipv4
switch(config-router-multicast-ipv4)# multipath deterministic router-id

The following displays the switch before the configuration.

sswitch(config-router-multicast-ipv4)# show active all
router multicast
   ipv4
      counters bytes
      activity polling-interval 60
      no routing
      multipath deterministic
      max-fastdrops 1024
      unresolved cache-entries max 4000
      unresolved packet-buffers max 3
      software-forwarding kernel

The following displays the switch after the configuration.

switch(config-router-multicast-ipv4)# show active all
router multicast
   ipv4
      counters bytes
      activity polling-interval 60
      no routing
      multipath deterministic router-id
      max-fastdrops 1024
      unresolved cache-entries max 4000
      unresolved packet-buffers max 3
      software-forwarding kernel

Configuring MFIB

MFIB formats PIM and IGMP multicast routes for protocol-independent hardware packet forwarding and adds them to the hardware Multicast Expansion Table (MET) and the hardware FIB.

MFIB Polling Interval

The switch records activity levels for multicast routes in the MFIB after polling the corresponding hardware activity bits. The activity polling-interval command specifies the frequency at which the switch polls the hardware activity bits for the multicast routes.

Example

These commands set the MFIB activity polling period to 15 seconds.
switch(config)# router multicast
switch(config-router-multicast)# ipv4
switch(config-router-multicast-ipv4)# activity polling-interval 15
switch(config-router-multicast-ipv4)#

MFIB Fast Drops

In IP multicast protocols, every (S,G) or (*,G) route is associated with an inbound Reverse Path Forwarding (RPF) interface. Packets arriving on an interface not associated with the route may need CPU-dependent PIM processing, so packets received by non-RPF interfaces are sent to the CPU by default, causing heavy CPU processing loads.

Multicast routing protocols often do not require non-RPF packets; these packets do not require software processing. The CPU therefore updates the hardware MFIB with a fast-drop entry when it receives a non-RPF interface packet that PIM does not require. Additional packets that match the fast-drop entry are not sent to the system software.

Fast drop is enabled on all interfaces by default. The no ip mfib fastdrop command disables MFIB fast drop for the configuration mode interface.

Example

This command disables MFIB fast drop for the interface vlan 120.
switch(config)# interface vlan 120
switch(config-if-Vl120)# no ip mfib fastdrop
switch(config-if-Vl120)#

The ip mfib max-fastdrops command limits the number of fast-drop routes that the switchs MFIB table can contain. The default fast-drop route limit is 1024.

Example

This command sets the maximum number of fast-drop routes to 2000.
switch(config)# ip mfib max-fastdrops 2000
switch(config)#

The clear ip mfib fastdrop command, in global configuration mode, removes all MFIB fast-drop entries on all interfaces.

Example

This command removes all fast-drop entries from the MFIB table.
switch# clear ip mfib fastdrop
switch#
The show multicast fib ipv4 command displays information about the routes and interfaces in the IPv4 MFIB.
  • show multicast fib ipv4 displays MFIB information for hardware-forwarded routes.
  • show multicast fib ipv4 software displays MFIB information for software-forwarded routes.

Example

This command displays MFIB information for hardware-forwarded routes.
switch# show multicast fib ipv4 
Activity poll time: 60 seconds
239.255.255.250 172.17.26.25
    Vlan26 (iif)
    Vlan2028
    Cpu
      Activity 0:02:11 ago
239.255.255.250 172.17.26.156
    Vlan26 (iif)
    Vlan2028
    Cpu
      Activity 0:02:11 ago
239.255.255.250 172.17.26.178
    Vlan26 (iif)
    Vlan2028
    Cpu
      Activity 0:03:37 ago
switch#

MFIB Unresolved Cache-entries Max

The unresolved cache-entries max command configures the maximum number of unresolved (S,G) routes that the switch can cache packets. All packets belonging to (S,G) routes exceeding the limit are dropped. The default buffer size is 4000 routes. See ip multicast boundary to limit the number of cached packets per S,G.

Example

This command sets the maximum MFIB unresolved cache-entry buffer size to 6000 routes in the default VRF.
switch(config)# router multicast
switch(config-router-multicast)# ipv4
switch(config-router-multicast-ipv4)# unresolved cache-entries max 6000
switch(config-router-multicast-ipv4)#

MFIB Unresolved Packet-buffers Max

The ip multicast boundary command specifies the number of packets per unresolved route that are queued while the route is being resolved by the switch. The limit for ip multicast boundary is for an individual route, packets that exceed this limit are dropped. By default, the switch processes three unresolved packets for an individual route. See unresolved cache-entries max to limit the number of unresolved routes that are cached.

Example

This command configures the switch in the default VRF to cache up to 30 multicast packets from any route before that route is resolved.
switch(config)# router multicast
switch(config-router-multicast)# ipv4
switch(config-router-multicast-ipv4)# unresolved packet-buffers max 30
switch(config-router-multicast-ipv4)#

Configuring Static Multicast

Use the route command to configure the Static Multicast in the Router Multicast mode.

Example
switch(config)# router multicast
switch(config-router-multicast)# route

Configuring Static Multicast routes for a VRF

The Static Multicast route can be configured on a VRF in the Router Multicast VRF IPv4 Configuration mode. Note, static multicast commands belong in the router multicast mode. To maintain backward compatibility for default VRF, static multicast commands for default VRF can be entered without changing to router multicast mode.

Example

switch(config)# router multicast
switch(config-router-multicast)# route

Source address can be optionally entered. When no source address is entered, it is assumed to be 0.0.0.0.

switch(config-router-multicast)# route 1.1.1.1 10.1.1.1
switch(config-router-multicast)# route 1.1.1.1 10.1.1.1 iif

Note, the IIF must belong to the same VRF for which the command is being executed for the configuration to take effect.

switch(config-router-multicast)# route 1.1.1.1 10.1.1.1 iif ethernet 
switch(config-router-multicast)# route 1.1.1.1 10.1.1.1 iif ethernet 30 
switch(config-router-multicast)# route 1.1.1.1 10.1.1.1 iif ethernet 30 oif

Multiple interfaces can be entered following the OIF. However, OIF is also optional. When there are no OIFs, then traffic for the S,G on the incoming interface is dropped.

switch(config-router-multicast)# route 1.1.1.1 10.1.1.1 iif ethernet 30 oif ethernet
switch(config-router-multicast)# route 1.1.1.1 10.1.1.1 iif ethernet 30 oif ethernet 30 ethernet 32
switch(config-router-multicast)# route 1.1.1.1 10.1.1.1 iif ethernet 30 oif ethernet 30 ethernet 32 cpu priority

The CPU option can be used to have CPU in the OIF set, it is optional. The priority is an optional and the value ranges from 1 to 255. By default, the value is 255.

switch(config-router-multicast)# route 1.1.1.1 10.1.1.1 iif ethernet 30 oif ethernet 30 ethernet 32 cpu priority 40

Displaying Static Multicast Information

Use the show multicast fib ipv4 command verify the status of the Static Multicast configured interfaces.

switch# show multicast fib ipv4
Activity poll time: 60 seconds
  225.1.1.1 10.1.1.1
    Ethernet1 (iif)
    Ethernet2
    Cpu

Displaying and Clearing the Mroute Table

The mroute table stores the states of inbound and outbound interfaces for each source/group pair (S,G). The switch discards and forwards packets on the basis of this state information. Each table entry, referred to as an mroute, corresponds to a unique (S,G) and contains:
  • the multicast group address
  • the multicast source address (or * for all sources)
  • the inbound interface
  • a list of outbound interfaces

Clearing mroute Entries

The clear ip mroute command removes route entries from the mroute table:
  • clear ip mroute * all entries from the mroute table.
  • clear ip mroute gp_ipv4 all entries for the specified multicast group.
  • clear ip mroute gp_ipv4 src_ipv4 all entries for the specified source sending to a specified group.
Examples
  • This command removes all route entries from the mroute table.
    switch# clear ip mroute *
    switch#
  • This command removes entries for source 228.3.10.1 sending to multicast group 224.2.205.42.
    switch# clear ip mroute 224.2.205.42 228.3.10.1
    switch#

Displaying the mroute Table

The show ip mroute count command displays IP multicast routing table statistics.

Example

This command displays IP multicast routing table statistics.
switch# show ip mroute count
IP Multicast Statistics
1 groups and 1 sources
Multicast routes: 1 (*,G), 1 (S,G)
Average of 1.00 sources per group
Maximum of 1 sources per group:
228.24.12.1
switch>
The show ip mroute command displays information from the IP multicast routing table.
  • show ip mroute displays information for all routes in the table.
  • show ip mroute gp_addr displays information for the specified multicast group.

Example

This command displays the IP multicast routing table for the multicast group 225.1.1.1.
switch# show ip mroute 225.1.1.1
PIM Sparse Mode Multicast Routing Table
Flags: E - Entry forwarding on the RPT, J - Joining to the SPT
R - RPT bit is set, S - SPT bit is set
W - Wildcard entry, X - External component interest
I - SG Include Join alert rcvd, P - Ex-Prune alert rcvd
H - Joining SPT due to policy, D - Joining SPT due to protocol
Z - Entry marked for deletion
A - Learned via Anycast RP Router
225.1.1.1
172.28.1.100, 5d04h, flags: S
Incoming interface: Vlan281
Outgoing interface list:
Port-Channel999
switch>

Multicast Commands

activity polling-interval

The switch records activity levels for multicast routes in the mfib after polling the corresponding hardware activity bits. The activity polling-interval command specifies the frequency at which the switch polls the hardware activity bits for the multicast routes.

The no activity polling-interval and default activity polling-interval commands restore the default interval of 60 seconds by removing the activity polling-interval command from running-config.

Command Mode

Router Multicast IPv4 Configuration

Command Syntax

activity polling-interval period

no activity polling-interval

default activity polling-interval

Parameter

period interval (seconds) between polls. Values range from 1 to 60. Default is 60.

Example

These commands set the MFIB activity polling period to 15 seconds.
switch(config)# router multicast
switch(config-router-multicast)# ipv4
switch(config-router-multicast-ipv4)# activity polling-interval 15
switch(config-router-multicast-ipv4)#

clear ip mfib fastdrop

The clear ip mfib fastdrop command removes all fast-drop entries from the MFIB table.

Command Mode

Privileged EXEC

Command Syntax

clear ip mfib fastdrop

Example

This command removes all fast-drop entries from the MFIB table.
switch# clear ip mfib fastdrop
switch#

clear ip mroute

The clear ip mroute command removes route entries from the mroute table, as follows:
  • clear ip mroute * removes all entries from the mroute table.
  • clear ip mroute gp_ipv4 removes all entries for the specified multicast group.
  • clear ip mroute gp_ipv4src_ipv4 removes all entries for the specified source sending to the specified group.

Command Mode

Privileged EXEC

Command Syntax

clear ip mroute ENTRY_LIST

Parameters

ENTRY_LIST entries that the command removes from the mroute table. Options include:
  • * all route entries.
  • gp_ipv4 all entries for multicast group gp_ipv4 (dotted decimal notation)
  • gp_ipv4 src_ipv4 all entries for source (src_ipv4) sending to group (gp_ipv4)
Examples
  • This command removes all route entries from the mroute table.
    switch# clear ip mroute *
    switch#
  • This command removes entries for the source 228.3.10.1 sending to multicast group 224.2.205.42.
    switch# clear ip mroute 224.2.205.42 228.3.10.1
    switch#

clear ip multicast counters

To clear per multicast route ingress counters or clear counters for a particular multicast route, use the clear ip multicast counters command.

Command Mode

EXEC

Command Syntax

clear ip multicast [vrf [vrf-name]] counters group_addr source_addr

Parameters
  • vrf vrf-name VRF name.
  • counters Counter for bytes/packets.
  • group_addr Group address.
  • source_addr Source address.

hardware counter feature multicast ipv4

Use the hardware counter feature multicast ipv4 command to enable per multicast router ingress packets and byte counters. The no and default forms of the command disables the feature. The feature is disabled by default.

Command Mode

Configuration mode

Command Syntax

hardware counter feature multicast ipv4

no hardware counter feature multicast ipv4

default hardware counter feature multicast ipv4

Example

On DCS-7020R, DCS-7280R/R2 and 7500R/R2 platforms, create and apply user defined TCAM profile with multicast counter feature db enabled. This example creates a profile copying it from the default, then modifying the profile.
switch(config)# hardware tcam
switch(config-hw-tcam)# profile <profileName> copy default
switch(config-hw-tcam-profileName)# feature counter multicast ipv4
switch(config-hw-tcam-profileName-feature-counter-multicast-ipv4))# exit
switch(config-hw-tcam-profileName)# no feature mirror ip
switch(config-hw-tcam-profileName)# exit
switch(config-hw-tcam)# system profile <profileName>

ip mfib fastdrop

In IP multicast protocols, every (S,G) or (*,G) route is associated with an inbound Reverse Path Forwarding (RPF) interface. Packets arriving on an interface not associated with the route may need CPU-dependent PIM processing, so packets received by non-RPF interfaces are sent to the CPU by default, causing heavy CPU processing loads.

Multicast routing protocols often do not require non-RPF packets; these packets do not require software processing. The CPU therefore updates the hardware MFIB with a fast-drop entry when it receives a non-RPF interface packet that PIM does not require. Additional packets that match the fast-drop entry are not sent to the system software.

Fast drop is enabled on all interfaces by default. The no ip mfib fastdrop command disables MFIB fast drop for the configuration mode interface.

The ip mfib fastdrop and default ip mfib fastdrop commands enable MFIB fast drop for the configuration mode interface by removing the corresponding no ip mfib fastdrop command from running-config.

The clear ip mfib fastdrop command, in the global configuration mode, removes all MFIB fast-drop entries on all interfaces.

Command Mode

Interface-Ethernet Configuration

Interface-Port-channel Configuration

Interface-VLAN Configuration

Command Syntax

ip mfib fastdrop

no ip mfib fastdrop

default ip mfib fastdrop

Example

This command disbles MFIB fast drop for interface vlan 120.
switch(config)# interface vlan 120
switch(config-if-Vl120)# no ip mfib fastdrop
switch(config-if-Vl120)#

ip mfib max-fastdrops

The ip mfib max-fastdrops command limits the number of fast-drop routes that the switchs MFIB table can contain.

The no ip mfib max-fastdrops and default ip mfib max-fastdrops commands restore the default fast-drop route limit of 1024 by removing the ip mfib max-fastdrops command from running-config.

Command Mode

Global Configuration

Command Syntax

ip mfib max-fastdrops quantity

no ip mfib max-fastdrops

default ip mfib max-fastdrops

Parameters

quantity maximum number of fast-drop routes. Value ranges from 0 to 1000000 (one million). Default is 1024.

Example

This command sets the maximum number of fast-drop routes to 2000.
switch(config)# ip mfib max-fastdrops 2000
switch(config)#

ip mroute

The ip mroute command configures the Static Mroute on the switch.

The no ip mroute and default ip mroute commands remove the specified static mroute from running-config.

Command Mode

Global Configuration

Command Syntax

ip mroute [source-prefix | source-address mask] [rpf-interface | rpf-neighbor] [admin distance]

Example

This command configures a Static IP mroute for a source 1.1.1.1/32 with an administrative distance 20 on interface ethernet 2/1.
switch(config)# ip mroute 1.1.1.1/32 ethernet 2/1 20 

ip multicast boundary

The ip multicast boundary command specifies subnets where source traffic entering the configuration mode interface is dropped, preventing the creation of mroute states on the interface. The interface is not included in the Outgoing Interface List (OIL). The multicast boundary can be specified through multiple IPv4 subnets or one standard IPv4 ACL.

In an ACL method, the multicast subnets are allowed only from the permit entries of the ACL and rest is either denied or filtered. Whereas, in a non-ACL method the statements configure subnets that are only denied or filtered.

Multicast PIM, IGMP and other multicast data cannot cross the boundary, facilitating the use of a multicast group address in multiple administrative domains.

The no ip multicast boundary and default ip multicast boundary commands delete the specified subnet restriction by removing the corresponding ip multicast boundary command from running-config. When these commands do not specify a subnet address, all ip multicast boundary statements for the configuration mode interface are removed.

Command Mode

Interface-Ethernet Configuration

Interface-Port-channel Configuration

Interface-VLAN Configuration

Command Syntax

ip multicast boundary SUBNET [TCAM]

no ip multicast boundary [SUBNET]

default ip multicast boundary [SUBNET]

Parameters
  • SUBNET the subnet address configured as the multicast boundary. Options include:
    • net_addr multicast subnet address (CIDR or address mask).
    • acl_name standard access Control List (ACL) that specifies the multicast group addresses.
  • TCAM specifies address inclusion in the routing table. Options include:
    • no parameter boundaries ((S,G) entries) are added to routing table.
    • out boundaries are not added to routing table.

Guidelines

When out is selected, the first inbound data packet corresponding to the SUBNET may be sent to the CPU. In response, the packet is dropped and the boundary prefix is added to the hardware table. In this scenario, the mroute entry is added only when data traffic is received.

Restrictions

Only one command that specifies an ACL can be assigned to an interface. Commands that specify an ACL and a subnet cannot be simultaneously assigned to an interface.

Examples
  • This command configures the multicast address of 229.43.23.0/24 as a multicast boundary where source traffic is restricted from interface vlan 300.
    switch(config)# interface vlan 300
    switch(config-if-vl300)# ip multicast boundary 229.43.23.0/24
    switch(config-if-vl300)#
  • These commands create a standard ACL, then implement the ACL in an ip multicast boundary command to allow multicast for subnet (224.0.0.0/4) and create a multicast boundary for all remaining subnets by denying them.
    switch(config)# ip access-list standard mbac1
    switch(config-std-acl-mbac1)# 10 deny 225.123.0.0/16
    switch(config-std-acl-mbac1)# 20 deny 239.120.10.0/24
    switch(config-std-acl-mbac1)# 30 permit 224.0.0.0/4
    switch(config-std-acl-mbac1)# exit
    switch(config)# interface vlan 200
    switch(config-if-Vl200)# ip multicast boundary mbac1
    switch(config-if-Vl200)# exit
    switch(config)#

ip multicast static

The ip multicast static command enables static multicast routing on the switch.

The exit command returns the switch to global configuration mode.

Command Mode

Interface Ethernet Configuration

Command Syntax

ip multicast static

Example

The following commands configure the static multicast routing on the switch.
switch(config)# interface ethernet 1/2
switch(config-if-Et1/2)# no switchport 
switch(config-if-Et1/2)# ip address 1.1.1.1/24
switch(config-if-Et1/2)# ip multicast static

mld last-listener-query-count

The mld last-listener-query-count command specifies the number of query messages the switch sends in response to a group-specific or group-source-specific leave message.

After receiving a message from a host leaving a group, the switch sends query messages at intervals specified by mld last-listener-query-interval. If the switch does not receive a response to the queries after sending the number of messages specified by this parameter, it stops forwarding messages to the host.

The no mld last-listener-query-count and default mld last-listener-query-count commands reset the last-listener-query-count to the default value by removing the corresponding mld last-listener-query-count command from the running-config. Default value is 2.

Command Mode

Interface-Ethernet Configuration

Command Syntax

mld last-listener-query-count number

no mld last-listener-query-count

default mld last-listener-query-count

Parameter

number the last listener query count. Values range from 0 to 100. Default value is 2.

Example

This command configures the last listener query count to 3 on an interface Ethernet 1.
switch(config)# interface Ethernet 1
switch(config-if-Et1)# mld last-listener-query-count 3

mld last-listener-query-interval

The mld last-listener-query-interval command configures the switchs transmission interval for sending group-specific or group-source-specific query messages from the configuration mode interface.

When a switch receives a message from a host that is leaving a group, it sends query messages at intervals set by this command. The mld last-listener-query-count specifies the number of messages that are sent before the switch stops forwarding packets to the host.

If the switch does not receive a response after this period, it stops forwarding traffic to the host on behalf of the group, source, or channel.

The no mld last-listener-query-interval and default mld last-listener-query-interval commands reset the last-listener-query-interval to the default value by removing the corresponding mld last-listener-query-interval command from the running-config. Default value is 1 second.

Command Mode

Interface-Ethernet Configuration

Command Syntax

mld last-listener-query-interval period

no mld last-listener-query-interval

default mld last-listener-query-interval

Parameter

period the last listener query interval in seconds. Values range from 1 to 3175.

Example

This command configures the last listener query interval to 2 seconds on an interface Ethernet1.
switch(config) #interface Ethernet1
switch(config-if-Et1)# mld last-listener-query-interval 2

mld query-interval

The mld query-interval command configures the frequency at which the configuration mode interface, as an MLD querier, sends host-query messages.

An MLD querier sends host-query messages to discover the multicast groups that have members on networks attached to the interface. The switch implements a default query interval of 125 seconds.

The no mld query-interval and default mld query-interval commands reset the query interval to the default value by removing the corresponding mld query-interval command from the running-config.

Command Mode

Interface-Ethernet Configuration

Command Syntax

mld query-interval period

no mld query-interval

default mld query-interval

Parameters

period the interval between query messages in seconds. Values range from 1 to 3175.

Example

This command configures the query interval of 30 seconds on an interface Ethernet1.
switch(config)# interface Ethernet1
switch(config-if-Et1)# mld query-interval 30

mld query-response-interval

The mld query-response-interval command configures the maximum response time that the recipient can wait before responding with a membership report on receipt of a general query.

The no mld query-response-interval and default mld query-response-interval commands reset the query interval to the default value by removing the corresponding mld query-response-interval command from the running-config.

Command Mode

Interface-Ethernet Configuration

Command Syntax

mld query-interval period

no mld query-interval

default mld query-interval

Parameter

period the query response interval in seconds. Values range from 1 to 3175.

Example

This command configures the query response interval of 30 seconds on an interface Ethernet1.
switch(config)# interface Ethernet1
switch(config-if-Et1)# mld query-response-interval 30

mld robustness

The mld robustness command configures the number of general queries to be sent before the router assumes there are no more listeners.

The no mld robustness and default mld robustness commands reset the robustness to the default value by removing the corresponding mld robustness command from the running-config.

Command Mode

Interface-Ethernet Configuration

Command Syntax

mld robustness robust_value

no mld robustness

default mld robustness

Parameter

robust_value the robustness count. Values range from 1 to 100.

Example

This command configures the robustness value to 2 on an interface Ethernet1.
switch(config)# interface Ethernet1
switch(config-if-Et1)# mld robustness 2

mld snooping

Multicast Listener Discovery (MLD) snooping constrains the flooding of IPv6 multicast traffic on VLANs and IGMP snooping for IPv4 environments. When MLD snooping is enabled on a VLAN, the device examines MLD messages between the hosts and multicast routers and learns which hosts are interested in receiving traffic for a multicast group. You can use the mld snooping command to configure MLDv2 snooping globally and per VLAN.

The no and the default forms of the command removes the mld snooping configuration.

Command Mode

Global configuration mode

Command Syntax

mld snooping

no mld snooping

default mld snooping

Example

The following example configures MLDv2 snooping globally and per VLAN.
switch(config)# mld snooping
switch(config-mld-snooping)# disabled
switch(config-mld-snooping)# vlan 1-100
switch(config-mld-snooping)# vlan 101
switch(config-mld-snooping-vlan-101)# disabled

mld startup-query-count

The mld startup-query-count command specifies the number of query messages that an interface sends during the startup query interval.

When an interface starts running MLD, it can establish the group state more quickly by sending query messages at a higher frequency. The mld startup-query-interval and mld startup-query-count commands define the startup period and the query message transmission frequency during that period.

The no mld startup-query-count and default mld startup-query-count commands restore the default startup-query-count value by removing the corresponding mld startup-query-count command from the running-config.

Command Mode

Interface-Ethernet Configuration

Command Syntax

mld startup-query-count number

no mld startup-query-count

default mld startup-query-count

Parameters

number the startup query count. Values range from 1 to 100.

Example

This command configures the startup query count of 4 on an interface Ethernet1.
switch(config)# interface Ethernet1
switch(config-if-Et1)# mld startup-query-count 4

mld startup-query-interval

The mld startup-query-interval command specifies the interval between the general queries sent by a querier on startup.

When an interface starts running MLD, it can establish the group state quicker by sending query messages at a higher frequency. The mld startup-query-interval and mld startup-query-count commands define the startup period and the query message transmission frequency during that period.

The no mld startup-query-count and default mld startup-query-interval commands restore the default startup-query-interval value by removing the corresponding mld startup-query-interval command from the running-config.

Command Mode

Interface-Ethernet Configuration

Command Syntax

mld startup-query-interval period

no mld startup-query-interval

default mld startup-query-interval

Parameters

period the startup query interval in seconds. Values range from 1 to 3175.

Example

This command configures the startup query interval of 100 seconds on an interface Ethernet1.
switch(config)# interface Ethernet1
switch(config-if-Et1)# mld startup-query-interval 100

mld static-group

The mld static-group command configures the configuration mode interface as a static member of a specified multicast group. This allows the router to forward multicast group packets through the interface without otherwise appearing or acting as a group member. By default, static group memberships are not configured on any interfaces.

If the command includes a source address, only multicast group messages received from the specified host address are fast-switched. Otherwise, all multicast traffic of the specified group is fast-switched.

The no mld static-group and default mld static-group commands remove the configuration mode interfaces group membership by removing the corresponding mld startup-group command from the running-config.

Command Mode

Interface-Ethernet Configuration

Command Syntax

mld static-group source_address [group_address | access-list acl_name]

no mld static-group source_address [group_address | access-list acl_name]

default mld static-group source_address [group_address | access-list acl_name]

Parameters
  • source_address IP address of the host that originates multicast data packets.
  • group_address IPv6 address of a multicast group.
  • access-list IPv6 access list to use as a static group list.
  • acl_name specifies access-list name
Examples
  • This command configures static groups on an interface Ethernet1.
    switch(config)# interface Ethernet1
    switch(config-if-Et1)# mld static-group ff30::1 a::1
  • This command configures multiple static groups using an access list on an interface Ethernet1.
    switch(config)# interface Ethernet1
    switch(config-if-Et1)# mld static-group access-list testaccessList

mld

The mld command enables multicast listener discovery on an interface which controls the flow of layer 3 IPv6 multicast traffic. Hosts request and maintain multicast group membership through MLD messages. Multicast routers use MLD to maintain a membership list of active multicast groups for each attached network.

The no mld and default mld commands restore the default behavior by removing the corresponding mld command from the running-config.

Note: It is possible to change the values of the querier parameters used by MLD.

Command Mode

Interface-Ethernet Configuration

Command Syntax

mld [last-listener-query-count | last-listener-query-interval | query-interval | query-response-interval | robustness | startup-query-count | startup-query-interval | static-group]

no mld

default mld

Parameters
  • last-listener-query-count the number of group-specific or group-source-specific queries to send before the router assumes there are no more listeners.
  • last-listener-query-interval the interval between the last listener queries.
  • query-interval the interval between the general queries regularly sent by a querier.
  • query-response-interval the interval that the host has to respond to a general query.
  • robustness the number of general queries to send before the router assumes there are no more listeners.
  • startup-query-count the number of queries a router sends at startup.
  • startup-query-interval the interval between the general queries sent by a querier at startup.
  • static-group the number of static groups or sources of MLD messages.

Example

This command enables MLD on the interface Ethernet1.
switch(config)# interface Ethernet1
switch(config-if-Et1)# mld

multipath deterministic

By default, multicast traffic is load balanced by distributing packets over all ECMP links. The no multipath deterministic command routes multicast ECMP traffic to the neighbor with the highest IPv4 address.

The multipath deterministic and default multipath deterministic commands restore the default behavior of randomly distributing multicast traffic over all ECMP links.

Command Mode

Router Multicast IPv4 Configuration

Command Syntax

multipath deterministic

no multipath deterministic

default multipath deterministic

Related Commands

The multipath none command performs the same function as no multipath deterministic.

Examples
  • These commands configure the switch to route multicast traffic through the ECMP link to the neighbor with the highest IP address.
    switch(config)# router multicast
    switch(config-router-multicast)# ipv4
    switch(config-router-multicast-ipv4)# no multipath deterministic
    switch(config-router-multicast-ipv4)#
  • These commands configure the switch to load balance multicast traffic by distributing packets over all ECMP links.
    switch(config)# router multicast
    switch(config-router-multicast)# ipv4
    switch(config-router-multicast-ipv4)# multipath deterministic
    switch(config-router-multicast-ipv4)#
  • These commands configure the switch to load balance multicast traffic by enabling the behavior of RPF selection.
    switch(config)# router multicast
    switch(config-router-multicast)# ipv4
    switch(config-router-multicast-ipv4)# multipath deterministic router-id
    switch(config-router-multicast-ipv4)#

multipath none

By default, multicast traffic is load balanced by distributing packets over all ECMP links. The multipath none command routes multicast ECMP traffic to the neighbor with the highest IPv4 address.

The no multipath none and default multipath none commands restore the default behavior of randomly distributing multicast traffic over all ECMP links by removing the multipath none command from running-config.

Command Mode

Global Configuration

Command Syntax

multipath none

no multipath none

default multipath none

Related Commands

The multipath deterministic commsnd performs the same function as no multipath none

Examples
  • These commands configure the switch to route multicast traffic through the ECMP link to the neighbor with the highest IP address.
    switch(config)# router multicast
    switch(config-router-multicast)# ipv4
    switch(config-router-multicast-ipv4)# multipath none
    switch(config-router-multicast-ipv4)#
  • These commands configure the switch to load balance multicast traffic by distributing packets over all ECMP links.
    switch(config)# router multicast
    switch(config-router-multicast)# ipv4
    switch(config-router-multicast-ipv4)# no multipath none
    switch(config-router-multicast-ipv4)#

route

The route command configures a static multicast route for the specified source, destination group, and incoming interface on the router.

The no route and default route commands remove the specified static multicast route by removing the corresponding route command from running-config.

Command Mode

Router Multicast IPv4 Configuration

Router Multicast VRF IPv4 Configuration

Command Syntax

route group_address [source_address] iif interface [oif interface] [cpu] [iifFrr interface] [priority priority_num]

no route group_address

default route group_address

Parameters
  • group_address the multicast group address.
  • source_address the optional source address for the multicast route.
  • iif interface specifies an incoming interface for the static route.
  • cpu optionally mirrors multicast packets to the CPU.
  • oif interface specifies an optional outgoing interface to be included among those on which the multicast traffic is forwarded.
  • iifFrr interface specifies an optional interface for multicast-only fast reroute.
  • interface options include:
    • Ethernet ethernet_port Ethernet interface.
    • Null0 drops all traffic.
    • Port-Channel lag_no port-channel interface or sub-interface; values range from 1-2000 or 1-2000.1-4094.
    • Register0 drops all incoming traffic.
    • Vlan vlan_no VLAN interface.
  • priority priority_num specifies an optional priority for the multicast route. If the same route is present in several multicast routing tables, the priority number is used to select the best available route. Values range from 0 to 255; PIM routes by default have a priority of 0, while static multicast routes by default have a priority of 255.

Example

These commands create a static multicast route in the default VRF. The static route has a group address of 225.3.3.3 and source address of 1.1.1.1. It uses Vlan100 as its incoming interface, VLANs 200 and 300 as its outgoing interfaces, and interface Ethernet2 as its multicast-only fast reroute interface.
switch(config)# router multicast
switch(config-router-multicast)# ipv4
switch(config-router-multicast-ipv4)# route 225.3.3.3 1.1.1.1 iif Vlan100 oif 
Vlan200 Vlan300 iifFrr Ethernet2
switch(config-router-multicast-ipv4)#

router multicast

The router multicast command places the switch in router-multicast configuration mode to configure IPv4 and IPv6 router multicast traffic.

Command Mode

Global Configuration

Command Syntax

router multicast

Example

The following command places the switch in router-multicast configuration mode.
switch(config)# router multicast
switch(config-router-multicast)# ipv6
switch(config-router-multicast-ipv6)#routing

routing

The routing command allows the switch to forward multicast packets. Multicast routing is disabled by default.

The no routing and default routing commands disable multicast routing by removing the routing command from running-config.

Command Mode

Router Multicast IPv4 Configuration

Router Multicast VRF IPv4 Configuration

Command Syntax

routing

no routing

default routing

Example

These commands enable multicast routing on the switch.
switch(config)# router multicast
switch(config-router-multicast)# ipv4
switch(config-router-multicast-ipv4)# routing
switch(config-router-multicast-ipv4)#

rpf route

The rpf route command specifies a candidate for the multicast Reverse Path Forwarding (RPF) interface of any (S,G) multicast route (mroute), where the source falls within the given network prefix. Static mroutes are stored in a separate routing table, the Multicast Routing Information Base (MRIB).

Command Mode

Router Multicast IPv4 Configuration

Router Multicast VRF IPv4 Configuration

Command Syntax

rpf route {source_prefix | source_address | mask}{rpf_interface | rpf_neighbor>} [admin_distance]

no rpf route {source_prefix | source_address | mask}{rpf_interface | rpf_neighbor}

default rpf route {source_prefix | source_address mask}{rpf_interface | rpf_neighbor}

Parameters
  • source_prefix specifies the source prefix.
  • source_address specifies the source address.
  • mask specifies the address mask.
  • rpf_interface specifies the multicast RPF interface.
  • rpf_neighbor specifies the multicast RPF neighbor.
  • admin_distance specifies the administrative distance (optional). Values range from 1 to 255.
Examples
  • These commands select the longest match when a source matches multiple static mroutes in the MRIB.
    switch(config)# router multicast
    switch(config-router-multicast)# ipv4
    switch(config-router-multicast-ipv4)# rpf route 10.0.0.0/16 Ethernet 4
    switch(config-router-multicast-ipv4)# rpf route 11.10.1.0/24 Ethernet 5
    switch(config-router-multicast-ipv4)# rpf route 11.10.1.2/32 Ethernet 6
    switch(config-router-multicast-ipv4)# 
  • These commands include an administrative distance of 255 on interface Ethernet 5 with static mroute.
    switch(config)# router multicast
    switch(config-router-multicast)# ipv4
    switch(config-router-multicast-ipv4)# rpf route 10.0.0.0/16 Ethernet 4
    switch(config-router-multicast-ipv4)# rpf route 11.10.1.0/24 Ethernet 5 255
    switch(config-router-multicast-ipv4)# rpf route 11.10.1.2/32 Ethernet 6
    switch(config-router-multicast-ipv4)# 

show ip mfib counters

Use the show ip mfib counters command to display per multicast route ingress packet and byte counters.

Command Mode

EXEC

Command Syntax

show ip mfib vrf [vrf-name] group_addr source_addr counters

Parameters
  • vrf [vrf-name] VRF name.
  • group_addrGroup address.
  • source_addrSource address.
  • countersCounter for bytes/packets.

Example

switch# show ip mfib 225.1.2.1 10.46.1.2 counters 
Activity poll time: 60 seconds
   225.1.2.1 10.46.1.2
      Byte: 1200200
      Packet: 12002
      Ethernet46 (iif)
      Ethernet47
      Activity 0:02:52 ago
switch#

show ip mroute

The show ip mroute command displays information from the IP multicast routing table.
  • show ip mroute displays information for all routes in the table.
  • show ip mroute gp_addr displays information for the specified multicast group.

Command Mode

EXEC

Command Syntax

show ip mroute

show ip mroute gp_addr

Parameters

gp_addr group IP address (dotted decimal notation).

Example

This command displays the IP multicast routing table entry for the multicast group 225.1.1.11.
switch# show ip mroute 225.1.1.1
PIM Sparse Mode Multicast Routing Table
Flags: E - Entry forwarding on the RPT, J - Joining to the SPT
R - RPT bit is set, S - SPT bit is set
W - Wildcard entry, X - External component interest
I - SG Include Join alert rcvd, P - Ex-Prune alert rcvd
H - Joining SPT due to policy, D - Joining SPT due to protocol
Z - Entry marked for deletion
A - Learned via Anycast RP Router
225.1.1.1
172.28.1.100, 5d04h, flags: S
Incoming interface: Vlan281
Outgoing interface list:
Port-Channel999
switch#

show ip mroute count

The show ip mroute count command displays IP multicast routing table statistics.

The show ip mroute command displays information from the IP multicast routing table.

Command Mode

EXEC

Command Syntax

show ip mroute count

Example

This command displays IP multicast routing table statistics.
switch# show ip mroute count
IP Multicast Statistics
1 groups and 1 sources
Multicast routes: 1 (*,G), 1 (S,G)
Average of 1.00 sources per group
Maximum of 1 sources per group:
228.24.12.1
switch#

show ip multicast boundary

The show ip multicast boundary command displays the summary of all IP multicast boundaries across all interfaces.

Command Mode

EXEC

Command Syntax

show ip multicast boundary [group_prefix | group_prefix/length [out] | interface {ethernet e_num | loopback l_num | management m_num | port-channel p_num | vlan v_num} | out]

Parameters
  • no parameters displays the summary of all IP multicast boundaries across all interfaces.
  • group_prefix displays the list of IP multicast boundaries matching the specified group address with subnet mask.
  • group_prefix/length displays the list of IP multicast boundaries matching the specified group address with CIDR notation. Option includes:
    • out displays the specified group addresss IP multicast boundaries whose control plane filtering is enabled.
  • interface displays IP multicast boundary of the specified interface. Options include:
    • ethernet e_num displays IP multicast boundaries of the specified Ethernet interface.
    • loopback l_num displays IP multicast boundaries of the specified Loopback interface.
    • management m_num displays IP multicast boundaries of the specified management interface.
    • port-channel p_num displays IP multicast boundaries of the specified port channel interface.
    • vlan v_num displays IP multicast boundaries of the specified VLAN interface.
  • out displays all IP multicast boundaries whose only control plane filtering is enabled.
Examples
  • This command displays the summary of all IP multicast boundaries across all interfaces.
    switch(config-if-Et24)# show ip multicast boundary
    Interface Denied Prefix Data Plane Filtered
    Ethernet1 224.5.5.0/24 Yes
    Ethernet1 224.6.6.0/24 Yes
    Ethernet2 224.4.4.0/24 Yes
    Ethernet3 224.5.5.0/24 No
  • This command displays all IP multicast boundaries matching 224.5.5.0 255.255.255.255.
    switch(config-if-Et24)# show ip multicast boundary 224.5.5.0 255.255.255.255
    Interface Denied Prefix Data Plane Filtered
    Ethernet1 224.5.5.0 255.255.255.255
    Ethernet3 224.5.5.0 255.255.255.255 No
  • This command displays all IP multicast boundaries matching 224.5.5.0/24.
    switch(config-if-Et24)# show ip multicast boundary 224.5.5.0/24
    Interface Denied Prefix Data Plane Filtered
    Ethernet1 224.5.5.0/24
    Ethernet3 224.5.5.0/24 No
  • This command displays all IP multicast boundaries of interface Ethernet1.
    switch(config-if-Et24)# show ip multicast boundary interface Ethernet1
    Interface Denied Prefix Data Plane Filtered
    Ethernet1 224.5.5.0/24 
    Ethernet1 224.6.6.0/24 No
  • This command displays the list of IP multicast boundaries whose only control plane filtering is enabled.
    switch(config-if-Et24)# show ip multicast boundary out
    Interface Denied Prefix Data Plane Filtered
    Ethernet1 224.5.5.0/24 No
    Ethernet3 224.5.5.0/24 No

show mld membership

The show mld membership command displays MLD group and source membership information on a specific interface.

Command Mode

EXEC

Command Syntax

show mld membership [dynamic | group | interface | static]

Parameters
  • dynamic displays MLD information for a dynamic group.
  • group displays MLD information for a specified multicast group address.
  • interface displays MLD information for the specified interface.
  • static displays MLD information for statically configured group.

Example

This command displays MLD group and source information on the Ethernet interfaces 3 and 6.
switch# show mld membership
Interface      Group        Source       Filter Mode 
---------      -----        ------       ----------- 
Ethernet3      ff30::1      a::2         include     
Ethernet3      ff30::1      a::1         include     
Ethernet6      ff30::2      a::2         include 

show mld querier

The show mld querier command displays information about the MLD querier and querier parameters.

Command Mode

EXEC

Command Syntax

show mld querier [interface | parameters]

Parameters
  • interface displays MLD querier information.
  • parameters displays MLD querier parameters.
Example
  • This command displays MLD querier on the Ethernet interface Et3 and Et6.
    switch# show mld querier 
    Interface    Querier                General    Other      Version   
                                        Query      Querier              
                                        Expiry     Expiry               
    ---------    -----------------      ---------- ---------  -------   
    Et3          fe80::1:ff:fe01:0      0:01:14    N/A        2
    Et6          fe80::1:ff:fe01:0      0:01:14    N/A        2
  • This command displays MLD querier parameters on the Ethernet interface Et3 and Et6.
    switch# show mld querier parameters
    Interface     Robustness Query      Query      Startup    Startup    Last       Last      
                             Interval   Response   Query      Query      Listener   Listener  
                                        Interval   Interval   Count      Query      Query     
                                                                         Interval   Count     
    ---------     ---------- --------   ---------  ---------  -------    --------   --------  
    Et3           2          125        10         31.25      2          1          2         
    Et6           2          125        10         31.25      2          1          2

show mld snooping

Use the show mld snooping command to display the snooping status of the switch.

Command Mode

EXEC

Command Syntax

show mld snooping [counters [errors] | groups [A:B:C:D:E:F:G:H | count | detail | local | mlag | user | vlan] | mrouter [detail | vlan] | querier [vlan] | vlan [num]]

Parameters
  • countersMLD counter information.
    • errorsError counters.
  • groupsMLD group information.
    • A:B:C:D:E:F:G:HIPv6 address.
    • countDisplays membership count.
    • detailDisplays a comprehensive output.
    • localDisplays groups learned locally via MLD.
    • mlagDisplays groups learned via MLAG peer.
    • userDisplays groups configured by the user.
    • vlanSpecifies VLAN.
  • mrouterMLD multicast router information.
    • detailDisplays a comprehensive output.
    • vlanSpecifies VLAN.
  • querierMLD querier information.
    • vlanSpecifies VLAN.
  • vlan Specifies VLAN.
    • num 1-4094 Identifier for Virtual LAN.
Examples
  • Use the show mld snooping command to display the MLD snooping status of the switch.
    switch# show mld snooping
       Global MLD Snooping configuration:
    -------------------------------------------
    MLD snooping                   : Enabled
    Robustness variable            : 2
    
    VLAN 1 :
    ----------
    MLD snooping                   : Disabled
    MLD max group limit            : No limit set
    Recent attempt to exceed limit : No
    MLD snooping pruning active    : False
    Flooding traffic to VLAN       : True
    VLAN 100 :
    ----------
    MLD snooping                   : Enabled
    MLD max group limit            : No limit set
    Recent attempt to exceed limit : No
    MLD snooping pruning active    : True
    Flooding traffic to VLAN       : False
    
    
    switch##show mld snooping vlan 100
       Global MLD Snooping configuration:
    -------------------------------------------
    MLD snooping                   : Enabled
    Robustness variable            : 2
    
    VLAN 100 :
    ----------
    MLD snooping                   : Enabled
    MLD max group limit            : No limit set
    Recent attempt to exceed limit : No
    MLD snooping pruning active    : True
    Flooding traffic to VLAN       : False
  • Use the show mld snooping groups command to display VLANs by group.
    switch# show mld snooping groups
    IGMP Snooping Group Membership
    EX : Filter mode Exclude
    IN : Filter mode Include
    IR : Ingress Replication
    VLAN  Group            Members
    ----  ---------------  -------------------
    100   ff05::2          Cpu, Et4
    100   ff08::11         Et1
    100   ff08::21         Et2
    100   ff08::31         Et3
    100   *                Et3, Et4
  • Use the show mld snooping groups detail command to display detailed VLANs information by group.
    switch(config-mld-snooping-vlan-100)# show mld snooping groups detail
    IGMP Snooping Group Membership
    EX : Filter mode Exclude
    IN : Filter mode Include
    IR : Ingress Replication
    VLAN  Group            Source           Mode  Uptime       Members
    ----  ---------------  ---------------  ----  -----------  ------------
    100   ff05::2          *                -     0d00h13m20   Cpu, Et4
    100   ff08::11         *                -     0d00h13m17   Et1
    100   ff08::21         1::1             IN    0d00h13m20   Et2
    100   ff08::31         2::1             EX    0d00h01m31   Et3
    100   *                *                -     -            Et3, Et4
    The show mld snooping groups command output can be further filtered to output just the:
    • local groups, That is groups learned locally using show mld snooping groups local command.
    • user groups, that is groups configured by user using the show mld snooping groups user command.
    • mlag groups, that is groups learned from the MLAG peer using the show mld snooping groups mlag command.
  • Use the show mld snooping mrouter to display MLD multicat router information.

    switch# show mld snooping mrouter
    Vlan    Interface-ports
    ------------------------------------------------------------
    100     Et3(dynamic), Et4(static)
    
    switch#show mld snooping mrouter detail
    Vlan   Intf      Address           FirstHeard   LastHeard    Expires  Type
    ---------------------------------------------------------------------------------
    100    Et3       fe80::200:3ff:fe01:0 0d00h24m30  0d00h00m08  00h00m17 querier
    100    Et4       fe80::200:3ff:fe03:0 0d00h24m10  0d00h00m08  00h01m37 pim
    100    Et2       0.0.0.0           -           -           -           static
    
    switch##show mld snooping mrouter vlan 100
    Vlan    Interface-ports
    ------------------------------------------------------------
    100     Et2(static), Et3(dynamic), Et4(dynamic)
    
    switch#show mld  snooping querier
    Vlan  IP Address               Version  Port
    --------------------------------------------
    100   fe80::200:3ff:fe01:0     v2       Et3
  • Use the show mld snooping querier command to display querier information. In the example, the querie information requested for display if for vlan 100.
    switch# show mld snooping querier vlan 100
    IP Address           : fe80::200:3ff:fe01:0
    MLD Version          : v2
    Port                 : Et3
    Max response time    : 10.0
    
    switch#show mld snooping counters
                    Input                 |    Output
    Port   Queries Reports  Others  Errors|Queries Reports  Others
    --------------------------------------------------------------
    Cpu          1     153       0       0     154       6      51
    Et1          0     153       0       0     156       0      51
    Et2          0     153       0       0     156     110      51
    Et3        154       1       0       0       1     610      51
    Et4          0     152      51       0     155     453       0
    switch       0       0       0       0       0       0       0
    
    switch#show mld snooping counters errors
               Packet       Packet  Bad IP    Unknown      Bad PIM   Bad ICMP  Bad MLD   Bad MLD
    Port       Too Short    Not IP  Checksum  IP Protocol  Checksum  Checksum  Query     Report
    ---------------------------------------------------------------------------------------------
    Cpu                0         0         0            0         0         0         0         0
    Et1                0         0         0            0         0         0         0         0
    Et2                0         0         0            0         0         0         0         0
    Et3                0         0         0            0         0         0         0         0
    Et4                0         0         0            0         0         0         0         0
    switch             0         0         0            0         0         0         0         0

    The switch interface in the above output can be ignored.

show mld statistics

The show mld statistics command displays total statistics information of incoming and outgoing MLD messages on a specific interface.

Command Mode

EXEC

Command Syntax

show mld statistics version value

Parameters
  • version specifies MLD version.
  • value specifies the MLD version number. Accepted version values are 1 and 2.

Example

This command displays total MLD statistics on the Ethernet interface Et3 and Et6.
switch# show mld statistics
             MLD Total (Version1 + Version2) Statistics
           Received                                  | Sent      
Interface  Queries  Reports  Dones   Others   Errors | Queries   
-----------------------------------------------------------------
Et3        0        12       0       0        0        12
Et6        0        11       0       0        0        12

show mld summary

The show mld summary command displays MLD summary information.

Command Mode

EXEC

Command Syntax

show mld summary

Parameters

interface displays MLD summary on a specified interface.

Example

This command displays MLD summary on the interface Ethernet3 and Ethernet6.
switch# show mld summary 
Interface     IPv6 link-local address      Group Count     Querier State  
---------     -----------------------      -----------     -------------  
Ethernet3     fe80::1:ff:fe01:0            2               querier        
Ethernet6     fe80::1:ff:fe01:0            2               querier        

Number of MLD interfaces: 2
Number of total groups joined across all MLD interfaces: 4

show multicast fib ipv4 software

The show multicast fib ipv4 software command displays information about the interfaces and the software-forwarded routes included in the IPv4 multicast forwarding information base (MFIB). Use the show multicast fib ipv4 command for hardware-forwarded routes.

Parameter options are available to filter output by group address or group and source address.

Command Mode

EXEC

Command Syntax

show multicast fib ipv4 software [INFO_LEVEL] [ROUTE]

Parameters
  • INFO_LEVEL specifies the type of information displayed. Options include
    • no parameter displays packet reception counters.
    • detail displays packet reception counters and packet queued/dropped counters.
    :
  • ROUTE routes displayed, filtered by multicast group and source IP addresses:
    • no parameter shows information for all software-forwarded routes in the MFIB.
    • group_addr shows information only for the specified multicast group.
    • group_addr source address shows information only for the specified group and source.
Examples
  • This command displays MFIB information for all software-forwarded routes in the MFIB.
    switch# show multicast fib ipv4 software
    239.255.255.250 172.17.41.150
            Vlan3040 (iif)
            Packets Received: 18
            Bytes Received  : 9147
            RPF Failures    : 0
    239.255.255.250 172.17.41.120
            Vlan3040 (iif)
            Packets Received: 6
            Bytes Received  : 966
            RPF Failures    : 0
    switch#
  • This command displays detailed MFIB information for all software-forwarded routes in the MFIB.
    switch# show multicast fib ipv4 software detail
    239.255.255.250 172.17.41.150
    Vlan3040 (iif)
    Packets Received: 18
    Bytes Received: 9147
    RPF Failures: 0
    Packets Queued/Dropped : 0 / 0
    239.255.255.250 172.17.41.120
    Vlan3040 (iif)
    Packets Received: 6
    Bytes Received: 966
    RPF Failures: 0
    Packets Queued/Dropped : 0 / 0
    switch#

show multicast fib ipv4

The show multicast fib ipv4 command displays information about interfaces and the hardware-forwarded routes included in the IPv4 Multicast Forwarding Information Base (MFIB).

Command Mode

EXEC

Command Syntax

show multicast fib ipv4 [group_address [source_address] | bidirectional | count | counter | df | rpa | software | sparse-mode | static | summary | vrf]

Parameters
  • no parameters displays information for all hardware-forwarded routes in the MFIB.
  • group_address displays the information of the specified multicast group address. Options include:
    • source_address displays the information of the specified multicast group and source addresses.
    • count displays the multicast routes count of the specified group address.
    • counters displays the multicast route traffic count of the specified group address.
  • bidirectional displays the information of bidirectional routes.
  • count displays the count of multicast routes.
  • counter displays the count of multicast route traffic in either bytes or packets.
  • df displays the bidirectional Protocol Independent Multicast (PIM) Designated Forwarder (DF) bitmap.
  • rpa displays the bidirectional PIM Rendezvous Point Address (RPA) index.
  • software displays the software multicast FIB.
  • sparse-mode displays the sparse-mode information.
  • static displays the static multicast information.
  • summary displays the multicast FIB summary.
  • vrf vrf_name displays information of the corresponding VRF.

Guidelines

The counter is not available (N/A) if a multicast route does not have an associated counter. If the counter value for any source in a group address is N/A, then the sum of counters for the group address is N/A. However, the counter values for other sources are still displayed.

Examples
  • This command displays the bidirectional PIM RPA index.
    switch# show multicast fib ipv4 rpa
    Prefix                                   Rpa Index
    225.0.0.0/8                              1
    226.0.0.0/8                              1
  • This command displays the static multicast route information.
    switch# show multicast fib ipv4 static count
    (S,G) routes: 34
    (*,G) routes: 31
    Fastdrop routes:  0
    Prefix routes: 12
  • This command displays the multicast routes count of the specified group and source addresses.
    switch# show multicast fib ipv4 229.0.0.0 10.1.5.101 count
    Activity poll time: 60 seconds
    (S,G) routes:  1
    Fastdrop routes:  0
  • This command displays the multicast route traffic count of the specified group and source addresses.
    switch# show multicast fib ipv4 229.0.0.0 10.1.5.101 counters
    Activity poll time: 60 seconds
     229.0.0.0 10.1.5.101
       Byte: 46128
       Packet: 93
       Port-Channel100 (iif)
         Activity 0:53:52 ago
  • This command displays the multicast FIB summary.
    switch# show multicast fib ipv4 summary
    Number of multicast routes: 12
    Number of fastdrop routes : 45

show multicast fib ipv6

The show multicast fib ipv6 command displays the Multicast Forwarding Information Base (MFIB) table.

Command Mode

EXEC

Command Syntax

show multicast fib ipv6

Example

The command output displays the Multicast Forwarding Information Base (MFIB) table as shown.
switch# show multicast fib ipv6
Activity poll time: 60 seconds
  ff33::1:0:0:1 101:1::2
    Ethernet11/1 (iif)
    Ethernet9/1.1
    Ethernet2/1.1
    Ethernet3/1.1
    Ethernet6/1.1
    Ethernet5/1.1
    Ethernet8/1.1
    Ethernet7/1.1
    Ethernet4/1.1
Activity 0:00:35 ago

show pim ipv6 sparse-mode route

The show pim ipv6 sparse-mode route command displays the PIM Sparse Mode Multicast Routing table.

Command Mode

EXEC

Command Syntax

show pim ipv6 sparse-mode route

Example

The command output displays the PIM Sparse Mode Multicast Routing table as shown.
switch# show pim ipv6 sparse-mode route
PIM Sparse Mode Multicast Routing Table
Flags: E - Entry forwarding on the RPT, J - Joining to the SPT
    R - RPT bit is set, S - SPT bit is set, L - Source is attached
    W - Wildcard entry, X - External component interest
    I - SG Include Join alert rcvd, P - (*,G) Programmed in hardware
    H - Joining SPT due to policy, D - Joining SPT due to protocol
    Z - Entry marked for deletion, C - Learned from a DR via a register
    A - Learned via Anycast RP Router, M - Learned via MSDP
    N - May notify MSDP, K - Keepalive timer not running
    T - switching Incoming Interface, B - Learned via Border Router
RPF route: U - From unicast routing table
           M - From multicast routing table
ff33::1:0:0:1
  101:1::2, 2:03:00, flags: S
    Incoming interface: Ethernet11/1
    RPF route: [U] 101:1::/64 [110/1] via fe80::464c:a8ff:feb7:39e9
    Outgoing interface list:
      Ethernet6/1.1
      Ethernet4/1.1
      Ethernet7/1.1
      Ethernet9/1.1
      Ethernet8/1.1
      Ethernet2/1.1
      Ethernet5/1.1
      Ethernet3/1.1

show platform fap mroute ipv6

The show platform fap mroute ipv6 command displays the Platform Hardware Forwarding table.

Command Mode

EXEC

Command Syntax

show platform fap mroute ipv6

Example

The command output displays the Platform Hardware Forwarding table as shown
switch# show platform fap mroute ipv6
Jericho0 Multicast Routes:
--------------------------
Location    GroupId    Group              Source                            
IIF           McId        OIF
  FLP/TT               FLP/TT         TT                            
FLP                  FLP           FLP                FLP
---------------------------------------------------------------------
4096/2048   1/1      ff33::1:0:0:23/128  101:1::2/128                    
Vlan1357 21504     Vlan1044(Et7/1) Vlan1123(Et9/1)         
                                                                                                                                                             
Vlan1200(Et8/1) Vlan1223(Et2/1)
                                                                                                                                                             
Vlan1226(Et5/1) Vlan1232(Et3/1)

unresolved cache-entries max

The unresolved cache-entries max command configures the maximum number of unresolved (S,G) routes that the switch can cache packets. The default buffer size is 4000 (S,G) routes.

The no unresolved cache-entries max and default unresolved cache-entries max commands restore the default unresolved cache-entries buffer size of 4000 (S,G) routes by removing the unresolved cache-entries max command from running-config. See ip multicast boundary to limit the number of cached packets per S,G.

Command Mode

Router Multicast IPv4 Configuration

Router Multicast VRF IPv4 Configuration

Command Syntax

unresolved cache-entries max quantity_entries

no unresolved cache-entries max

default unresolved cache-entries max

Parameter

quantity_entries maximum buffer size (routes). Value ranges from 10 to 10000000. Default is 4000.

Example

This command sets the maximum MFIB unresolved cache-entry buffer size to 6000 routes in the default VRF.
switch(config)# router multicast
switch(config-router-multicast)# ipv4
switch(config-router-multicast-ipv4)# unresolved cache-entries max 6000
switch(config-router-multicast-ipv4)#

unresolved packet-buffers max

The unresolved packet-buffers max command specifies the number of (S,G) multicast packets for an individual route that the switch can process before the (S,G) entry is entered into cache. Packets that are received in excess of this limit before the route is programmed into the cache are dropped. By default, the switch processes 3 unresolved packets for an individual route.

The no unresolved packet-buffers max and default unresolved packet-buffers max commands restore the number of unresolved packets that the switch processes to the default value of 3 packets by removing the unresolved packet-buffers max command from running-config. See unresolved cache-entries max to limit the number of unresolved routes that are cached.

Command Mode

Router Multicast IPv4 Configuration

Router Multicast VRF IPv4 Configuration

Command Syntax

unresolved packet-buffers max quantity_packets

no unresolved packet-buffers max

default unresolved packet-buffers max

Parameters

quantity_packets packets per unresolved route that the switch processes. Values range from 3 to 10000000. Default is 3.

Example

This command programs the switch in the default VRF to process 30 multicast packets from any route regardless of its entrys presence in the multicast routing cache.
switch(config)# router multicast
switch(config-router-multicast)# ipv4
switch(config-router-multicast-ipv4)# unresolved packet-buffers max 30
switch(config-router-multicast-ipv4)#