400GBASE ZR transceiver is the industry’s first multi vendor DWDM standard, a Digital Coherent Optical module

This article describes a feature for Tap Aggregation mode, which strips IEEE 802.1BR E-Tag and Cisco VN-Tag headers from all tagged packets received on tap interface before delivering them out of tool interfaces.

802.1X is an IEEE standard protocol that prevents unauthorized devices from gaining access to the network.

Filtered Mirroring allows certain packets to be selected for mirroring, rather than all packets ingressing or egressing a particular port.

This feature allows the global configuration, "allow non ect or non ect packet thresholds" along with "set drop

BFD (Bidirectional Forwarding Detection) session telemetry allows for the collection of per session statistics as

BGP Add Path TX allows for a BGP speaker to advertise multiple paths (instead of a single best path) for a prefix towards

EOS 4.21.3F introduces support for BGP Flowspec, as defined in RFC5575 and RFC7674. The typical use case is to filter or redirect DDoS traffic on edge routers.

The BGP graceful restart mechanism has a limitation that the graceful restart time cannot exceed 4095 seconds per the

BGP Non Stop Forwarding (NSF) aims to minimize the traffic loss when the the following scenarios occur:

This feature adds support for BGP peering with multiple peers using the same IP address. The router id of those peers is

CLI extension allows for custom CLIs commands/modes to be defined in EOS. It also integrates with EOS SDK to be able to control a daemon’s configuration and read a daemon’s status from the CLI command handlers. This feature is intended to have more customization compared to the “daemon cli” feature, which only allows for key/value pairs as cli commands, and doesn’t allow for custom CLI commands. It does this by using a statically defined YAML file that contains the daemon definition (EOS SDK or not), CLI mode, and CLI commands, very much akin to what is provided by the via configuration in the daemon cli mode.

DHCP Relay feature forwards DHCP packets between client and server when the DHCP Server is not in the same broadcast domain as the client. DHCP Relay should be configured on the gateway interface (SVI/ L3 interface ) for the clients. DHCP Relay agent creates a new unicast DHCP packet and sets the giaddr field to the ‘primary’ IP address of the interface on which DHCP request packet is received. The modified request packet is then relayed to one or more configured DHCP servers. DHCP server assigns ip address to client from the pool corresponding to giaddr field.

EOS supports the DHCP Relay feature, which relays DHCP Requests/Responses between DHCP clients and DHCP servers in different subnets. 

The Dot1x Dropped Counters count the packets that get dropped for dot1x interfaces. The following

The feature allows to create a named TC to DSCP mapping that can be applied on an interface.DSCP of routed packets egressing out of the interface will be rewritten according to the map.

The feature allows assigning of class E addresses to interfaces by default with no option to turn that off and routing

Generic UDP Encapsulation (GUE) is a general method for encapsulating packets of arbitrary IP protocols within a UDP tunnel. GUE provides an extensible header format with optional data. In this release, decap capability of GUE packets of variant 1 header format has been added. This variant allows direct encapsulation using the UDP header without the GUE header. The inner payload could be one of IPv4, IPv6, or MPLS.

This feature introduces the hardware forwarding support for IPv4 over IPv4, GRE-Tunnel interfaces on Arista Switches. A GRE-Tunnel interface acts as a logical interface which performs the GRE encapsulation or decapsulation.

The Segment security feature provides the convenience of applying policies on segments rather than interfaces or subnets. Hosts/networks are classified into segments based on prefixes. Grouping prefixes into segments allows for definition of policies that govern flow of traffic between segments.

Arista campus switches allow extensive and fine grained hardware based flow tracking and management features. They

This feature introduces the ability to match on 1) any BGP aggregate contributor or 2) a specific BGP aggregate’s

EOS 4.25.2F adds support for IS IS, OSPF and OSPFv3 Graceful Restart (GR) on unplanned software restarts for all

In EVPN deployment with VXLAN underlay when an EVPN type 5 prefix is imported into an IP VRF, the IGP cost of the underlay

InfluxDB telemetry streaming feature enables telemetry data collection with Telegraf on box, and allows streaming

The L2EVPN MPLS feature is available when configuring BGP in the multi agent routing protocol model.

In a multihomed EVPN MPLS configuration, BUM packets sent from a non-designated forwarder (Non-DF) PE to a designated forwarder (DF) PE must carry ESI label advertised by the egress DF PE.

A L2 sub-interface is a logical bridging endpoint associated with traffic on an interface distinguished by 802.1Q tags, where each <interface, 802.1q tag> tuple is treated as a first class bridging interface.


If a network device uses deep packet inspection for load balancing, RFC6790 recommends deployments to use entropy label in LDP to improve load balancing in MPLS networks by providing sufficient entropy in the label stack itself.

Line system commands are used to apply configuration and query the status of line system modules in EOS. The supported line system modules are the OSFP-AMP-ZR and the QSFP-AMP-ZR.

This feature allows classification of packets on QoS policy-maps based on the Class of Service (CoS), VLAN, Drop Eligible Indicator (DEI) in the 802.1q header of the packet. CoS (Class of Service) corresponds to the Priority code point (PCP) bits in the 802.1q header.

MPLS-over-GRE encapsulation support in EOS 4.17.0 enables tunneling IPv4 packets over MPLS over GRE tunnels. This feature leverages next-hop group support in EOS. With this feature, IPv4 routes may be resolved via MPLS-over-GRE next-hop group to be able to push one MPLS label and then GRE encapsulate the resulting labelled IPv4 packet before sending out of the egress interface.

The TCP MSS clamping feature involves clamping the maximum segment size (MSS) in the TCP header of TCP SYN packets if it exceeds the configured MSS ceiling limit for the interface. Clamping MSS value helps in avoiding IP fragmentation in tunnel scenarios by ensuring that MSS is small enough to accommodate the extra overhead of GRE and tunnel outer IP headers.

For an octal port such as a QSFPDD or OSFP, this feature renumbers the ports on a system to have 4 configurable

In a symmetric network topology, for the same ECMP (Equal Cost Multi Path) route programmed at different devices in a switch layer, the various devices can program ECMP next hops in the FEC (Forwarding Equivalence Class) for that route in varying orders.

This feature introduces the support for OSPF routes over GRE tunnels under default as well as non-default VRFs. The feature is disabled by default. 

This feature provides isolation and allows segregating/dividing the link state database based on interface. 

The current behaviour on R series products is to drop all packets marked for drop by the chip Packet Processor in the

This feature may be used for redistributing OSPFv2 leaked and non leaked routes from one instance to another when

Routes covered by a resilient equal cost multi path (RECMP) prefix are types of routes that make use of hardware tables

RSVP TE, the Resource Reservation Protocol (RSVP) for Traffic Engineering (TE), is used to distribute MPLS labels

Sampled flow tracking with IPFIX export is supported on most of the Arista platforms. User configured sampling rate is used for sampling in ingress and/or egress direction on the configured interfaces. An EOS software agent on CPU processes samples received from hardware, samples are used to create flow records that are exported to IPFIX collectors. Refer to Sampled flow tracking TOI for additional details.

This article describes the support for Filtered Mirroring using security ACL. The user can selectively mirror packets based on the statement in the configured IPv4, IPv6 or MAC ACL.

Segment Routing Traffic Engineering Policy (SR-TE) aka SR Policy makes use of Segment Routing (SR) to allow a headend to steer traffic along any path without maintaining per flow state in every node. A headend steers traffic into an SR Policy.

4.25.2F introduces storm control with packet per second support in the platforms listed below. TOI describing the

Storm control enables traffic policing on floods of packets on L2 switching networks. The documentation describes

Prior to 4.25.2F, support for BGP PIC was restricted to locally identifiable failures such as link failures. If a

The multicast route counters count packets and bytes per group, source and vrf. Every multicast route will be counted when the feature is turned on if there are sufficient hardware counter resources available. 

By default, sFlow samples that are generated have a fixed size: 128 bytes. This feature adds support for a

Sub-interfaces can be grouped into logical units called scheduling groups, which are shaped as a single unit. Each scheduling group may be assigned a scheduling policy which defines a shape rate in kbps and optionally a guaranteed bandwidth, also in kbps.