Decap Groups

These sections describe the Decap groups:

Decap Groups Description

The decap group is a data structure that receives encapsulated packets and extracts the payload. The switch then processes or forwards the extracted payload as required. Although packets cannot be transmitted through decap groups, nexthop groups can be used to create a packet's reverse path. Decap groups support payload extraction of packets received from Generic Routing Encapsulation (GRE) and IP-in-IP tunnels.

Decap groups have these limitations:

  • Tunnels are terminated using destination IP address; source IP address has no influence.
  • Packets matching a decap group are not processed through their ingress interface and VLAN.
  • During a tunnel termination, ingress ACL filter each decap group packet’s inner header.
  • Packet counters are not available.
  • VRF is not supported.

Decap groups are defined by their tunnel type and decap IP address:

  • Tunnel type specifies the tunnel protocol that the switch uses to extract payload.
  • Decap IP address specifies the IP address where the switch receives decap group packets.

Decap groups support Generic Routing Encapsulation (GRE) and IP-in-IP tunnels.

Decap Groups Configuration

Decap groups are configured in decap-group configuration mode. The decap-group configuration mode is not a group change mode; the running-config is changed immediately upon entering commands. However, when exiting, the decap-group configuration mode does not affect running-config. The exit command returns the switch to global configuration mode.

Decap groups do not define a default destination address or tunnel type and is not functional until both parameters are configured. A decap group can contain multiple tunnel decap-ip statements.

Example:
  • This command defines a static CLI entry for the incoming-label.
    switch(config)#mpls static top-label 3400 ethernet 3/3/3 10.14.4.4 pop payload-type ipv4
  • This command creates a decap group named DC-1 and configures the group to terminate packets from GRE tunnel packets with the destination IP address of 10.14.3.2
    switch(config)#ip decap-group DC-1
    switch(config-dg-DC-1)#tunnel type gre
    switch(config-dg-DC-1)#tunnel decap-ip 10.14.3.2
    switch(config-dg-DC-1)#show active
     ip decap-group DC-1
     tunnel type gre
     tunnel decap-ip 10.14.3.2
    switch(config-dg-DC-1)#end
    switch(config)#

Decap Commands

ip decap-group

The ip decap-group command places the switch in decap-group configuration mode, through which decap groups are created or modified. A decap group is a data structure that defines a method of extracting the payload from an encapsulated packet that the switch receives on a specified IP address.

Decap groups do not specify a default IP address group or tunnel type. These parameters must be explicitly configured before a decap group can function.

Decap-group configuration mode is not a group change mode; the running-config is changed immediately upon entering commands. Exiting the decap-group configuration mode does not affect running-config. The exit command returns the switch to global configuration mode.

The no ip decap-group and default ip decap-group commands delete previously configured commands in the specified decap-group mode.

Command Mode

Global Configuration

Command Syntax

ip decap-group group_name

no ip decap-group group_name

default ip decap-group group_name

Parameters

  • group_name Decap group name.
Commands Available in Decap-group Configuration Mode

Examples:

  • This command creates a decap group named DC-1.

    switch(config)#ip decap-group DC-1
    switch(config-dg-DC-1)#
  • This command exits decap-group mode for the DC-1 decap group.

    switch(config-dg-DC-1)#exit
    switch(config)#
  • This command delete the decap group named DC-1.

    switch(config)#no ip decap-group DC-1
    switch(config)#

show ip decap-group

The show ip decap-group command displays the IP decap groups that are available in the switch.

Command Mode

Global Configuration

Command Syntax

show ip decap-group [decap-group name | dynamic] Parameters
  • decap-group name      The decap group name.
  • dynamicDisplays the dynamic entries only.

Example:

This command displays the IP decap groups that are available in a switch.
switch(config)#show ip decap-group
NOTE: "D" column indicates dynamic entries
D | Name| Type | Info| Version | Addr Type
--|---------------------|------------|-----------------|---------|--------
* | d1| GRE| 1.2.3.4 | |
* | d2| IP-in-IP | Ethernet12/3| IPv4| primary
| gre-with-intf | GRE| | |
| ipip-with-decapall| IP-in-IP | all | IPv4| all
| ipip-with-decapall| IP-in-IP | all | IPv6| all
| ipip-with-intf| IP-in-IP | Ethernet11/3| IPv6| all
| ipip-with-intf| IP-in-IP | Ethernet11/3| IPv4| primary
* | ipip-with-ip| IP-in-IP | 1001::1 | IPv6|
* | ipip-with-ip| IP-in-IP | 1.1.1.1 | IPv4|
| p1| GRE| 100.100.100.100 | |
| p2| UNKNOWN| | |

tunnel decap-interface (Decap Group)

The tunnel decap-interface command adds all locally configured IP addresses to the specific Layer 3 interface per decap group.

The no tunnel decap-interface command and the default tunnel decap-interface command restores the default state by removing the locally added IP addresses from the decap group.

Command Mode

Decap-Group Configuration

Command Syntax

tunnel decap-interface{ Ethernet | Loopback | Management | Port-Channel | Tunnel | Vlan | Vxlan | all}

no tunnel decap-interface {Ethernet | Loopback | Management | Port-Channel | Tunnel | Vlan | Vxlan | all}

default tunnel decap-interface

{Ethernet | Loopback | Management | Port-Channel | Tunnel | Vlan | Vxlan | all}
Parameters
  • Ethernet e_num     Ethernet interface specified by e_num. The Ethernet port number ranges from 1 to 36.
  • Loopback l_num     Loopback interface specified by l_num. The loopback interface number ranges from 0 to 1000.
  • Management m_num     Management interface specified by m_num. The management port number ranges from 1 to 1.
  • Port-channel p_num     Port-channel interface specified by p_num. Options include:

    • Port-channel interface number. The port-channel interface number ranges from 1 to 2000.
    • Port-channel sub interface number. The port-channel sub interface number <1-2000>,<1-4094>.
  • tunnel t_num     Tunnel interface specified by t_num. The tunnel interface number ranges from 0 to 255.
  • vlan v_num     VLAN interface specified by v_num. The VLAN interface number ranges from 1 to 4094.
  • vxlan vx_num     VXLAN interface specified by vx_num. The VXLAN tunnel interface number ranges from 1 to 1.
  • all address-family     This parameter configures all L3 interfaces as a decap interface.

Example:

These commands add locally configured IP addresses to the Ethernet interface 1/1 for the dg1 decap group.
switch(config)#ip decap-group dg1
switch(config-dg-dg1)#tunnel decap-interface Ethernet1/1

switch(config-dg-dg1)#show active
ip decap-group dg1
 tunnel type ipip
 tunnel decap-interface Ethernet1/1
 tunnel decap-interface all address-family ipv6 address all

tunnel decap-ip (Decap Group)

The tunnel decap-ip command specifies the IP address of packets that are handled by the configuration mode decap group. A decap group is a data structure that defines a method of extracting the payload from an encapsulated packet that the switch receives on a specified IP address.

Decap groups do not define a default decap-ip address. A decap group is not functional until an IP address is specified. Decap groups can contain only one tunnel decap-ip statement; subsequent commands replace any previously configured statements.

Command Mode

Decap-Group Configuration

Command Syntax

tunnel decap-ip ipv4_address

Parameters
  • ipv4_addr An IPv4 address.
Related Commands

Guidelines

A decap group does not specify a default IP address group or tunnel type. These parameters must be explicitly configured before a decap group can function.

Example:

These commands configure 10.14.3.2 as the decap-IP address for the DC-1 decap group.
switch(config)#ip decap-group DC-1
switch(config-dg-DC-1)#tunnel decap-ip 10.14.3.2
switch(config-dg-DC-1)#show active
 ip decap-group DC-1
 tunnel decap-ip 10.14.3.2
switch(config-dg-DC-1)#

tunnel type (Decap Group)

The tunnel type command specifies the tunnel protocol for extracting payload from encapsulated packets that arrive on the IP address specified for the configuration mode decap group. Supported tunnel protocols include GRE (General Routing Encapsulation) and IP-in-IP.

Decap groups do not define a default tunnel type. A decap group is not functional until an IP address is specified. Decap groups can contain only one tunnel decap-ip statement; subsequent commands replace any previously configured statements.

Command Mode

Decap-group Configuration

Command Syntax

tunnel type gre

Related Commands

Guidelines

A decap group does not specify a default IP address group or tunnel type. These parameters must be explicitly configured before a decap group can function.

Example:

This command configures decap group DC-1 to terminate packets from GRE tunnel packets.
switch(config)#ip decap-group DC-1
switch(config-dg-DC-1)#tunnel type gre
switch(config-dg-DC-1)#show active
 ip decap-group DC-1
 tunnel type gre
switch(config-dg-DC-1)#