- Written by VICTOR WEN
- Posted on 4月 7, 2021
- Updated on 1月 5, 2026
- 15281 Views
EOS supports the DHCP Relay feature, which relays DHCP Requests/Responses between DHCP clients and DHCP servers in different subnets. However, the DHCP server does not have visibility of where the request originated from and can only make IP address allocation decisions based on the client MAC address alone (client MAC address is included in the DHCP packet as part of the payload). To remedy that, DHCP Option-82 was formalized to allow relay agents to include Remote ID and Circuit ID so that DHCP servers can apply a more intelligent allocation policy.
- Written by Bharath Somayaji
- Posted on 11月 22, 2017
- Updated on 3月 3, 2023
- 13192 Views
DHCPv6 Prefix Delegation support enables a DHCP relay agent to program routes for addresses assigned by a DHCP server. The assigned prefixes could either be DHCPv6 IA_PD prefix delegation addresses, or DHCPv6 IA_NA global /128 addresses.
- Written by Brandon Luong
- Posted on 2月 8, 2017
- Updated on 2月 9, 2017
- 10865 Views
Directed broadcast is method of transfer to send a packet to recipients in a target subnet. This is done by sending a
- Written by Kiranmayi Kasarapu
- Posted on 2月 8, 2017
- Updated on 4月 18, 2018
- 13713 Views
DirectFlow runs alongside the existing layer 2/3 forwarding plane, enabling a network architecture that
- Written by Anuraag Mittal
- Posted on 5月 1, 2015
- Updated on 5月 1, 2015
- 10793 Views
The following new enhancements to DirectFlow and/or OpenFlow are added in EOS 4.15.0F:. DirectFlow
- Written by Prachi Modi
- Posted on 5月 7, 2025
- Updated on 5月 7, 2025
- 2813 Views
With the 19.0 release, network administrators can turn off 802.11b rates on SSIDs operating in the 2.4 GHz band. Turning off these legacy rates enhances overall network performance and prevents the association from outdated 802.11b clients.
- Written by Wade Carpenter
- Posted on 5月 1, 2015
- Updated on 5月 1, 2015
- 10863 Views
IEEE802.1D 2004, Section 7.12.6 specifies destination MAC addresses that are normally trapped (not forwarded) by
- Written by Saket
- Posted on 3月 23, 2026
- Updated on 3月 23, 2026
- 439 Views
A policy-map defines a set of rules that prioritize network traffic, ensuring critical data isn't delayed by less important packets. Each policy-map aggregates multiple class-maps, which are associated with specific match criteria such as VLAN, DSCP, or IP ACLs. Actions — including DSCP marking, traffic-class assignment, and policing — can be applied to each policy-map and class-map pair. This allows specific QoS actions to be executed on every incoming packet based on defined parameters.
- Written by Jiaqi Lu
- Posted on 4月 24, 2025
- Updated on 4月 24, 2025
- 3077 Views
The Switch detail page in the DMF GUI has a new Inventory tab displaying information about optics, cables, and transceivers.
- Written by Suresh Narasimmamoorthy
- Posted on 5月 5, 2026
- Updated on 5月 5, 2026
- 215 Views
This document describes the updates to the DANZ Monitoring Fabric (DMF) 8.10 release verified scale and performance numbers.
- Written by Suresh Narasimmamoorthy
- Posted on 5月 2, 2025
- Updated on 5月 2, 2025
- 3029 Views
This document describes the updates to the DANZ Monitoring Fabric (DMF) 8.7 release verified scale and performance numbers.
- Written by Ivan Lum
- Posted on 5月 2, 2025
- Updated on 5月 2, 2025
- 3095 Views
The hardware support update details newly supported hardware and other changes in the DANZ Monitoring Fabric (DMF) release 8.7.0.
- Written by Suresh Narasimmamoorthy
- Posted on 9月 18, 2025
- Updated on 9月 18, 2025
- 1851 Views
This document describes the updates to the DANZ Monitoring Fabric (DMF) 8.8 release verified scale and performance numbers. Verified scale values for “DCA-DM-RN760” and “DCA-DM-RN760L” Recorder Nodes.
- Written by Ivan Lum
- Posted on 9月 18, 2025
- Updated on 9月 18, 2025
- 1888 Views
The hardware support update details newly supported hardware and other changes in the DANZ Monitoring Fabric (DMF) release 8.8.0.
- Written by Srilekha Nune
- Posted on 4月 29, 2025
- Updated on 4月 29, 2025
- 3084 Views
Egress Filtering is an option to send different traffic to each tool attached to the policy's delivery setting. It provides additional filtering at the delivery ports based on the egress filtering rules specified at the interface.
- Written by Lucas Currie
- Posted on 5月 5, 2026
- Updated on 5月 5, 2026
- 235 Views
The DMF 8.10.0 release introduces a completely redesigned Fabric page. This modernization effort improves visual clarity for data displays and the topology graph, providing an interactive fabric representation for a better understanding of device connectivity.
- Written by Paul McDade
- Posted on 5月 5, 2026
- Updated on 5月 5, 2026
- 231 Views
Match rules define the specific traffic forwarded through the fabric. These criteria are applied directly within a policy, as part of a rule within a referenced rule group, or as a post-service match in a managed service. Each rule specifies parameters such as IP addresses, protocols, and ports. This update introduces expanded matching capabilities and removes previous restrictions regarding the combination of match criteria, allowing for more granular traffic steering.
- Written by Matthieu Simon
- Posted on 4月 29, 2025
- Updated on 4月 29, 2025
- 3083 Views
As of DMF version 8.7.0, all DMF appliances will operate on the AlmaLinux 9.4 operating system, replacing the previous Ubuntu 20.04 LTS. This migration of the underlying operating system will not impact any currently supported features.
- Written by Ryan Izard
- Posted on 4月 29, 2025
- Updated on 4月 29, 2025
- 3067 Views
The DMF Recorder Node now supports deployment as a Virtual Machine (VM) for functional testing in Proof of Concept (POC) environments. Performance is limited and will vary based on allocated VM resources. DMF 8.7.0 and later Recorder Node images support being deployed as a VM.
- Written by Michael Theodore
- Posted on 5月 2, 2025
- Updated on 5月 2, 2025
- 3004 Views
This feature provides a method to rename a DMF object. DMF 8.7 Controllers support the Policy rename feature.
- Written by Siddharth Karandikar
- Posted on 3月 13, 2026
- Updated on 3月 13, 2026
- 472 Views
The DMF VN-TAG Decapsulation (decap) feature introduces native support for removing the VN-TAG header within the DMF platform. This capability is implemented directly on the DMF Service Node to process traffic frames, and it integrates comprehensive control plane support via the Controller schema and the standard CLI workflow.
- Written by Jeremy Fell
- Posted on 9月 18, 2025
- Updated on 9月 18, 2025
- 1893 Views
The DANZ Monitoring Fabric (DMF) allows the integration and monitoring of virtual machines in a VMware NSX fabric deployed in a vSphere environment. The DMF Controller communicates with NSX to retrieve its managed inventory and configures port mirroring sessions for selected virtual machines managed by the NSX fabric.
- Written by John Schimmel
- Posted on 5月 2, 2025
- Updated on 5月 2, 2025
- 3067 Views
The DANZ Monitoring Fabric (DMF) allows the integration and monitoring of virtual machines in a VMware NSX fabric deployed in a vSphere environment. The DMF Controller communicates with NSX to retrieve its managed inventory and configures port mirroring sessions for selected virtual machines managed by the NSX fabric.
- Written by Chitra Ramachandran
- Posted on 4月 2, 2026
- Updated on 4月 2, 2026
- 441 Views
The feature adds support for dynamic prefix-list to match on all protocol routes, and not just BGP. Dynamic prefix-list policy construct is similar to the traditional IP and IPv6 prefix-list, except that they have an additional state associated. This state associated with the dynamic prefix-lists, is determined on the basis of the route entries in FIB, and hence as and when the FIB changes, the state also changes dynamically.
- Written by Anand Narayanan Rao
- Posted on 7月 1, 2025
- Updated on 2月 4, 2026
- 2756 Views
Currently data packets going over a DPS+IPsec tunnel have a fixed source IP, destination IP, protocol, source port and destination port after encapsulation for a given DPS path. Because of this, there is no good way to load-balance the tunneled traffic. However, to improve performance there is a need to load-balance the tunneled traffic.
- Written by Mihyar Baroudi
- Posted on 12月 8, 2015
- Updated on 9月 17, 2018
- 13507 Views
With this feature, user can fetch various internal hardware drops info from each switch and isolate the switch or
- Written by Mohammed Alfatafta
- Posted on 3月 13, 2025
- Updated on 3月 18, 2025
- 3841 Views
Precision Time Protocol (PTP) management messages are general PTP messages sent to PTP-enabled switches on the data plane. On Arista switches, its behavior depends on the configured PTP mode. In Boundary Clock mode, they are handled by the control plane. In Transparent Clock mode, they are forwarded in the data plane. PTP management messages can be sent through the PTP network either in a multicast or unicast fashion (by using ptp forward unicast, see Forwarding Unicast PTP Packets in Boundary Mode).
- Written by Harish Prabhu
- Posted on 8月 31, 2023
- Updated on 5月 20, 2026
- 10611 Views
By default, the DSCP and ECN bits of VXLAN bridged packets are not rewritten. Currently, for bridged packets undergoing VXLAN encapsulation, the DSCP in the outer IP header is derived from TC and the ECN bits are set to zero. The desired behavior is that the outer IP header should be remarked with ingress packet DSCP and ingress packet ECN. Also, local congestion should be handled correctly.
- Written by Mihyar Baroudi
- Posted on 12月 8, 2015
- Updated on 2月 7, 2022
- 11103 Views
DCS 7280E. Arad QOS MAP:. This command assigns the DSCP rewrite value of 37 to traffic classes 2, 4, and 6.
- Written by Pandurangan R S
- Posted on 6月 29, 2016
- Updated on 9月 8, 2021
- 11332 Views
Dual Tag VLAN mapping feature defines mapping between (outer VID and inner VID of double tagged packet) and bridging
- Written by James Pang
- Posted on 5月 1, 2015
- Updated on 6月 28, 2021
- 13782 Views
Starting with EOS4.15.0F, dynamic and symmetric LAG hashing policies are supported on the 7500E platform. Dynamic
- Written by Anthony
- Posted on 12月 24, 2024
- Updated on 12月 24, 2024
- 4984 Views
Dynamic Explicit Congestion Notification (D-ECN) configures an ECN marking threshold that changes dynamically based on a transmit queue’s available shared buffers. A D-ECN offset and D-ECN floor is configured per unicast transmit queue which defines how the ECN marking threshold will change as the queue’s shared buffer limit changes.
- Written by Rabi Narayan
- Posted on 6月 28, 2024
- Updated on 11月 7, 2024
- 7996 Views
Until EOS release 4.32.0F, EOS allows users to statically configure link min-delay and max-delay used for IS-IS FlexAlgo. This feature adds support for dynamic measurement of link delay using the TWAMP Light protocol described in RFC 8186 and provides it to IS-IS FlexAlgo dynamically.
This document describes how to configure and monitor this feature.
- Written by Krzysztof Gongolewski
- Posted on 9月 11, 2022
- Updated on 3月 7, 2025
- 12141 Views
Dynamic NAT connection limit is a feature that provides the functionality to limit the number of dynamic NAT connections.
- Written by Mihyar Baroudi
- Posted on 12月 8, 2015
- Updated on 4月 23, 2021
- 11007 Views
Dynamic resizing of nexthop groups, as the name suggests, is a feature that enables a nexthop group to dynamically
- Written by Ziqian XU
- Posted on 11月 22, 2017
- Updated on 7月 21, 2023
- 10835 Views
This feature allows eAPI to run in multiple non default VRFs on the same physical router. In this way, users can
- Written by Lavanya Conjeevaram
- Posted on 6月 29, 2016
- Updated on 4月 22, 2024
- 15662 Views
ECMP Hash visibility CLI determines the output interface for an ECMP set based on the flow parameters supplied by the user. Ingress interface, source IP address, destination IP address and IP protocol are the required parameters. L4 source and destination ports and VLAN identifier are optional, but should be specified if the packet has them.
- Written by Guri
- Posted on 3月 12, 2026
- Updated on 3月 12, 2026
- 524 Views
By default EOS does not perform Overlay ECMP for hosts connecting to a Multihoming Ethernet segment in an Asymmetric-IRB setup. Instead it picks one of the paths statically for sending the traffic. This feature enables ECMP for the multihomed hosts connected in an EVPN VXLAN all active multihoming Asymmetric-IRB setup.
- Written by Sourabh Bollapragada
- Posted on 12月 22, 2020
- Updated on 3月 23, 2026
- 14059 Views
This feature supports counting ECN-marked packets (ECN = Explicit Congestion Notification) on a per egress port per tx-queue basis. The feature can be used to gather these packet counts via CLI or SNMP.
- Written by Nanda Kurella
- Posted on 11月 4, 2025
- Updated on 3月 18, 2026
- 7112 Views
Explicit Congestion Notification (ECN) is an extension to the Internet Protocol and to the Transmission Control Protocol which allows end-to-end notification of network congestion without dropping packets. ECN is an optional feature that is only used when both endpoints support it and are willing to use it. ECN operates over an active queue management algorithm.
- Written by Mihyar Baroudi
- Posted on 12月 8, 2015
- Updated on 12月 21, 2015
- 11818 Views
This feature provides the capability to count the number of packets hitting rules associated to egress ACLs applied
- Written by Sriharsha J
- Posted on 5月 1, 2015
- Updated on 5月 14, 2025
- 11617 Views
This feature allows generating the syslog message for the packets matching rules in egress ACLs. This can be enabled using the log keyword when configuring an ACL rule. A copy of the packet matching such an ACL rule is sent to the control plane, where a syslog entry for the packet header is generated.
- Written by Harish Pradyot
- Posted on 2月 27, 2025
- Updated on 2月 27, 2025
- 4184 Views
This feature enables users to configure MPLS EXP rewrite behavior on the egress interface based upon the global TC-to-EXP mapping. Starting from software version 4.33.2F, the CLI configuration to enable or disable EXP rewrite on the egress interface introduces a clear distinction in the behavior of MPLS EXP processing during POP and SWAP operations.
- Written by Gabor
- Posted on 8月 12, 2025
- Updated on 9月 18, 2025
- 3337 Views
Egress filtered mirroring enables the selective mirroring of packets exiting a port, offering more precise control compared to mirroring all egress traffic. It is possible to selectively mirror egress packets based on the permit statements in the configured ACLs.
- Written by Mouli Baskaran
- Posted on 5月 1, 2015
- Updated on 3月 19, 2016
- 10521 Views
IPv4/IPv6 over MPLS packets are now eligible for ACLs at egress stage by default. The feature is applicable only to
- Written by Sridhar Nagarajan
- Posted on 1月 8, 2026
- Updated on 1月 8, 2026
- 1048 Views
EOS-4.35.1F adds support for egress IPv4/IPv6/MAC PACL. So, by default, egress IPv4/IPv6 ACL enabled on default profile and for MAC ACL to enable, it is required to add its support directly to the current tcam profile or create a new tcam profile based on the default profile and disable egress IPv4 and IPv6 ACL features.
- Written by Denis Evoy
- Posted on 10月 24, 2024
- Updated on 10月 24, 2024
- 5061 Views
Normally, an ingress router has no control over an autonomous system border router’s (ASBR) selection of inter-AS links. In the example below, Peer 2 and Peer 3 both advertise reachability to some remote network to ASBR 1 (e.g. service route 172.16.1.0/24). ASBR 1 would then use normal bestpath selection rules to select a preferred egress path (for traffic flowing to that service route). However, this means that the ingress router has no control over which egress path is chosen.
- Written by Ganesh Priyatham Palivela
- Posted on 10月 10, 2025
- Updated on 10月 10, 2025
- 1948 Views
Egress Priority Tagging is a feature that allows a switch to send out priority tagged ethernet frames in place of untagged frames. Priority tagged frames are sent with the VLAN ID set to zero allowing downstream devices to read the 802.1p priority bits set in the VLAN header.
- Written by Tanuj Kumar Jhamb
- Posted on 2月 7, 2024
- Updated on 9月 16, 2025
- 7670 Views
sFlow is a sampling technique which monitors incoming traffic on all interfaces without affecting network performance. Egress sFlow is a feature which samples the packets in the egress pipeline for analytical purposes. Currently egress sFlow is only software based on Arista switches.
- Written by AKSHAYA Sridharan
- Posted on 12月 17, 2020
- Updated on 10月 22, 2025
- 13371 Views
Egress traffic-policing can be applied on L3 Ethernet subinterfaces for outbound traffic.
