- Written by Diksha Mahajan
- Posted on 3月 3, 2023
- Updated on 1月 8, 2026
- 10938 Views
A layer 3 subinterface is a logical endpoint associated with traffic on an interface distinguished by 802.1Q tags, where each interface, 802.1Q tag tuple, is treated as a routing interface.
- Written by Bin Wang
- Posted on 12月 22, 2020
- Updated on 1月 7, 2026
- 12192 Views
For various peering applications, there is a need to support the assignment of a MAC address on routed interfaces.
- Written by Shyam Kota
- Posted on 11月 6, 2019
- Updated on 1月 27, 2026
- 14237 Views
This feature allows setting the desired maximum VOQ latency. Drop probabilities are adjusted in hardware to meet this limit.
- Written by Can Sun
- Posted on 8月 12, 2025
- Updated on 1月 20, 2026
- 2350 Views
Measured boot is a tamper-detection mechanism that records a system's boot process. It calculates cryptographic hashes of system components and configurations, which are then securely stored in the Platform Configuration Registers (PCRs) of a Trusted Platform Module (TPM) chip. This process creates a secure "hash chain" of the boot sequence. After the system starts, the TPM Quote operation, along with the PCR extension records, can be used to verify the PCR values, confirming that the system components are unchanged and the software is trusted.
- Written by Alejandro Schwoykoski
- Posted on 12月 22, 2021
- Updated on 1月 20, 2026
- 19706 Views
MetaMux is an FPGA-based feature available on Arista’s 7130 platforms. It performs ultra-low latency Ethernet packet multiplexing with or without packet contention queuing. The port to port latency is a function of the selected MetaMux profile, front panel ingress port, front panel egress port, FPGA connector ingress port, and platform being used.
- Written by David Mirabito
- Posted on 12月 30, 2021
- Updated on 4月 6, 2026
- 30236 Views
MetaWatch is an FPGA-based feature available for Arista 7130 Series platforms. It provides precise timestamping of packets, aggregation and deep buffering for Ethernet links. Timestamp information and other metadata such as device and port identifiers are appended to the end of the packet as a trailer.
- Written by Dickson Chum
- Posted on 1月 3, 2023
- Updated on 1月 22, 2026
- 16266 Views
Mirroring to a GRE tunnel allows mirrored packets to transit to a L3 network using GRE encapsulation.
- Written by Siddarth Karki
- Posted on 3月 3, 2023
- Updated on 1月 16, 2026
- 10944 Views
From the 4.29.2F release of EOS, proactive probing of servers is supported. Using this feature Arista switches can continuously probe configured servers to check their liveliness and use the information obtained from these probes while sending out requests to the servers.
- Written by Diego Asturias
- Posted on 1月 30, 2024
- Updated on 4月 21, 2026
- 10461 Views
MultiAccess is a low latency FPGA-based Ethernet firewall or multiplexer/demultiplexer with configurable port ACLs (PACL). The MultiAccess FPGA application, which is delivered as an EOS extension in a “swix” file format includes various profiles which dictate and instantiate supported interface speeds and features. All MultiAccess profiles support MAC and IP PACLs, in either ingress, egress, or ingress and egress directions. Profiles may also perform packet multiplexing and demultiplexing, storm control, firewalling, and VLAN tunneling, all across various speeds and port layouts. MultiAccess’s port to port latency is a function of the selected MultiAccess profile, interfaces being used, interface configuration, and the platform itself. For latency details, please refer to the Latencies section of this TOI.
- Written by Bharathram Pattabhiraman
- Posted on 2月 11, 2021
- Updated on 4月 20, 2026
- 36064 Views
E-Tree is an L2 EVPN service (defined in RFC8317) in which each attachment circuit (AC) is assigned the role of Root or Leaf. Root ACs can communicate with leaf ACs and other root ACs. Leaf ACs can only communicate with root ACs. Leaf AC to leaf AC traffic is blocked. In this implementation, ACs are configured at the VLAN level, and the forwarding rules are enforced using a combination of local configuration of leaf VLANs (for local hosts), and asymmetric route targets (for remote hosts).
- Written by Shelly Chang
- Posted on 1月 6, 2026
- Updated on 1月 16, 2026
- 968 Views
Evpn multicast IRB allows multicast traffic from the external Pim domain to flow through the EVPN network via PIM EVPN Gateway Designated Router (PEG-DR). The solution won’t work when the external Pim source or RP is not connected to PEG-DR in the external Pim domain. EVPN Multicast Transit solves the issue by allowing any PEG with transit configured (PEG-Transit) to act as PEG-DR.
- Written by Prashant Srinivas
- Posted on 4月 25, 2022
- Updated on 1月 16, 2026
- 14595 Views
The solution described in this document allows multicast traffic arriving on a VRF interface on a Provider’s Edge (PE) router to be delivered to Customer’s Edge (CE) routers with downstream receivers in the same VPN.
- Written by Xuan Qi
- Posted on 4月 18, 2024
- Updated on 4月 7, 2026
- 8188 Views
This feature adds all-active (A-A) multihoming support on the multi-domain EVPN VXLAN-MPLS gateway. It allows L2 and L3 ECMP to form between the multihoming gateways on the TOR devices inside the site and on the gateways in the remote sites. Therefore, traffic can be load-balanced to the multi-homing gateway and redundancy and fast convergence can be achieved.
- Written by Jikai Yin
- Posted on 6月 29, 2016
- Updated on 1月 19, 2026
- 14461 Views
NAT peer state synchronization feature provides redundancy and resiliency for dynamic NAT across a pair of devices in an attempt to mitigate the risk of single NAT device failure. The main motivation is that since the NAT state is shared between two switches, the failure of one switch can be tolerated since the other switch will retain the translations.
- Written by Gowtham Rameshkumar
- Posted on 6月 10, 2019
- Updated on 4月 6, 2026
- 12967 Views
An introduction to Nexthop-groups can be seen in the Nexthop-Group section of EOS. With this feature, IP packets matching a static Nexthop-Group route can be encapsulated with a GRE tunnel and forwarded.
- Written by Aparna Karanjkar
- Posted on 6月 17, 2019
- Updated on 4月 2, 2026
- 15479 Views
EOS supports reading and streaming various OpenConfig configuration and state models over gNMI (gRPC Network Management Interface), RESTCONF, and NETCONF transports. A subset of the configuration models may also be modified over these transports
- Written by Julie Hakimi
- Posted on 1月 12, 2026
- Updated on 1月 12, 2026
- 839 Views
Priority-flow-control (PFC) buffer and history counters provide information on both present PFC pause conditions and past pause events. These buffer counters (since EOS-4.34.2F) and history counters (since EOS-4.35.0F) are available via OpenConfig in addition to the show commands that have existed in previous versions.
- Written by Sahil Midha
- Posted on 10月 16, 2025
- Updated on 3月 25, 2026
- 2123 Views
Packet trimming is a novel method for end-to-end congestion notification. When a packet is dropped in the MMU due to congestion, the dropped packet is trimmed and forwarded to the intended receiver with a new configured DSCP value. Upon receiving a trimmed packet, the receiver can perform appropriate handling to reduce transmission rate or retransmit any lost packets. The feature supports matching criteria via ingress traffic policy for selecting which packets should be trimmed when they get dropped in the MMU. Similarly, the rewritten DSCP is specified on a per egress port basis for trimmed packets egressing out of the switch to the intended destination. This per egress port DSCP overrides the global rewrite DSCP if configured. This feature is supported for protocols IPv4, IPv6 and SRv6.
- Written by Prashant Kumar
- Posted on 4月 30, 2025
- Updated on 1月 21, 2026
- 3158 Views
Policy-map counters can be configured to display per-interface counters for all class-maps attached to all successfully programmed policy-maps. The feature is not enabled by default and has to be configured through the command line interface. When enabled, the output of the show command will display both per-interface and aggregate counters.
- Written by Johnny Chen
- Posted on 4月 25, 2022
- Updated on 3月 9, 2026
- 12668 Views
The Per-MAC ACL feature provides the functionality to apply an IPv4/IPv6 ACL to a 802.1x supplicant instead of applying them on the port that the supplicant is behind. This allows for more flexible and specific traffic policies to be defined for supplicants trying to access certain resources on the network.
- Written by Yan Hua
- Posted on 8月 22, 2025
- Updated on 4月 2, 2026
- 2045 Views
This document covers the usage of port-breakout CLI to break a port evenly into multiple interfaces. In the context of this document, a port is a logical entity that holds a list of interfaces, in most cases this is equivalent to the front panel transceiver cage.
- Written by Yin Chen
- Posted on 10月 30, 2023
- Updated on 4月 14, 2026
- 9718 Views
This article provides a general introduction to Precision Time Protocol (PTP) supported within EOS. PTP is aimed at distributing time with sub-microsecond accuracy. PTP support is based on the IEEE-1588 specification for version 2 of the protocol.
- Written by David Cronin
- Posted on 3月 3, 2022
- Updated on 3月 5, 2026
- 33017 Views
Routing control functions (RCF) is a language that can be used to express route filtering and attribute modification logic in a powerful and programmatic fashion.This document serves as a reference guide for Routing protocol attributes, Operators for comparing and modifying attributes, built-in functions provided in RCF
- Written by David Cronin
- Posted on 3月 3, 2022
- Updated on 3月 5, 2026
- 20323 Views
Routing control functions (RCF) is a language that can be used to express route filtering and attribute modification logic in a powerful and programmatic fashion.This document serves as a reference guide for Bgp agent points of application:
- Written by Shamit Kapadia
- Posted on 5月 3, 2022
- Updated on 3月 10, 2026
- 13216 Views
Routing control functions (RCF) is a language that can be used to express route filtering and attribute modification logic in a powerful and programmatic fashion.
- Written by David Cronin
- Posted on 3月 4, 2022
- Updated on 1月 22, 2026
- 27172 Views
Routing control functions (RCF) is a language that can be used to express route filtering and attribute modification logic in a powerful and programmatic fashion.
- Written by Kalash Nainwal
- Posted on 12月 14, 2020
- Updated on 4月 20, 2026
- 18518 Views
RSVP-TE, the Resource Reservation Protocol (RSVP) for Traffic Engineering (TE), is used to distribute MPLS labels for steering traffic and reserving bandwidth. The Label Edge Router (LER) feature implements the headend functionality, i.e., RSVP-TE tunnels can originate at an LER which can steer traffic into the tunnel.
- Written by Wenyi Cheng
- Posted on 1月 19, 2026
- Updated on 1月 19, 2026
- 665 Views
This document outlines a new CLI command, send security-bundle. This feature is motivated by the need for a streamlined way to collect forensic and security-related artifacts from a switch for analysis by security teams. It parallels the existing send support-bundle command, which is used to gather troubleshooting data. It is suggested to use the security-bundle together with the support-bundle command in order to obtain all data necessary to support an incident.
- Written by Sanjay Subramanya
- Posted on 1月 27, 2026
- Updated on 1月 29, 2026
- 649 Views
Load Balancing on Service Leaf MLAG is a feature designed to support optimal load balancing of traffic sent to a ZTX Monitor Node cluster. The load balance functionality is essential to ensure that bi-directional flows land on the same ZTX Monitor Node in the cluster as all members of the ZTX Monitor Node cluster advertise a common anycast GRE endpoint.
- Written by Sebastian Fiorini
- Posted on 8月 18, 2025
- Updated on 1月 21, 2026
- 1972 Views
The sFlow VLAN forwarding feature adds support for providing the VLAN by which the packet is bridged as opposed to the VLAN that is decoded from the Ethernet frame. The VLANs are reported in the sFlow extended switch header’s input VLAN and output VLAN fields, as defined in the sFlow extended switch data.
- Written by Hari Prasad S R
- Posted on 8月 19, 2025
- Updated on 1月 12, 2026
- 2605 Views
"Micro segment" (SRv6 uSID or uSID for short) is an extension of SRv6 architecture, specifically designed to represent SRv6 SIDs in an extremely compact way. It addresses the overhead of using full 128-bit IPv6 SIDs for routing. Instead of using a 128-bit address for single SID, multiple uSIDs are packed into a single 128-bit address. Each 128-bit address comprises a block value representing the domain followed by multiple uSIDs, each of the same bit length. If there are bits left they are filled with trailing zeros. This allows for a complete SRv6 path to be represented by a 128-bit IPv6 address. Like a regular SID, each uSID is associated with a specific behavior on the SRv6 capable node. SRv6 uN refers to the End behavior with uSIDs.
- Written by Thejesh Panchappa
- Posted on 5月 1, 2015
- Updated on 1月 19, 2026
- 14788 Views
This is an infrastructure that provides management of SSL certificates, keys and profiles. SSL/TLS is an application-layer protocol that provides secure transport between client and server through a combination of authentication, encryption and data integrity. SSL/TLS uses certificates and private-public key pairs to provide this security. A user can manage certificates, keys and also multiple SSL profiles. An SSL profile is a configuration which includes certificate, key and trusted CA certificates used in SSL/TLS communication. An SSL profile configuration can be attached to another EOS configuration which supports SSL/TLS communication. Individual EOS features that use this infrastructure will document the details of using an SSL profile in their configuration.
- Written by Vincent (Chia Hsuan)
- Posted on 9月 24, 2024
- Updated on 1月 8, 2026
- 6961 Views
A traffic storm is a flood of packets entering a network, resulting in excessive traffic and degraded performance. Storm control prevents network disruptions by limiting traffic beyond specified thresholds on individual physical LAN interfaces. Storm control monitors inbound traffic levels over one-second intervals and compares the traffic level with a specified benchmark. The storm-control command configures and enables storm control on the configuration mode physical interface
- Written by Christopher Brown
- Posted on 1月 8, 2026
- Updated on 1月 8, 2026
- 803 Views
The aggregate address minimum contributors feature adds the capability to specify a minimum number of contributor routes that must be present and advertisable in order for the BGP speaker to generate the route for the aggregate address.
- Written by Deepanshu Shukla
- Posted on 8月 21, 2020
- Updated on 1月 12, 2026
- 22301 Views
This feature adds support for “Dynamic Load Balancing (DLB)” on Equal Cost Multi Path (ECMP) groups.
- Written by Yuanzhi Gao
- Posted on 10月 14, 2019
- Updated on 1月 5, 2026
- 9373 Views
Nexthop Group tunnels are a tunneling abstraction in EOS. A nexthop group tunnel consists of a tunnel endpoint (IP prefix) and a nexthop group name representing the underlying nexthop group that forwards the traffic. If the underlying nexthop group is not configured, the tunnel endpoint will be unreachable until the given nexthop group is configured.
- Written by Mehul Mistry
- Posted on 8月 12, 2025
- Updated on 3月 17, 2026
- 2471 Views
Port isolation is a feature that segregates the ports in a VLAN broadcast domain into isolated and non-isolated ports and facilitates blocking traffic between ports marked as isolated. Isolated ports in a VLAN are the ports that cannot send/receive traffic from other isolated ports in the same VLAN. However, they should still be able to communicate with non-isolated ports
- Written by Basil Saji
- Posted on 11月 9, 2020
- Updated on 1月 20, 2026
- 17472 Views
Private VLAN is a feature that segregates a regular VLAN broadcast domain while maintaining all ports in the same IP subnet. There are three types of VLAN within a private VLAN
- Written by Jeff Chan
- Posted on 8月 19, 2020
- Updated on 4月 14, 2026
- 36258 Views
Access Control Lists (ACL) use packet classification to mark certain packets going through the packet processor pipeline and then take configured action against them. Rules are defined based on various fields of packets and usually TCAM is used to match packets to rules. For example, there can be a rule to match the packet source IP address against a list of IP addresses, and drop the packet if there is a match. This will be expressed in TCAM with multiple entries matching the list of IP addresses. The number of entries is reduced by masking off bits, if possible. TCAM is a limited resource, so with classifiers having a large number of rules and a big field list, TCAM runs out of resources.
- Written by Eddie Xie
- Posted on 1月 31, 2024
- Updated on 4月 17, 2026
- 6186 Views
This TOI supplements the Ingress Traffic Policy applied on ingress port interfaces. Please refer to that document for a description of Traffic Policies and field-sets. This TOI explains the Traffic Policies as applied in the ingress direction on VLAN interfaces. For Traffic Policies on the egress direction of VLAN interfaces, see the Egress Traffic Policy TOI.
- Written by Vallela Kaushik Shashank Reddy
- Posted on 6月 20, 2022
- Updated on 1月 16, 2026
- 6821 Views
This feature enables the support of applying a policy-map in egress direction on an SVI interface. A policy-map is a QoS feature in which we have multiple class-maps each with a match criteria and an action. These class-maps match on the given criteria and the configured action is applied on the traffic which matches. We can apply these policy-maps on interfaces in both input and output directions which match on ingress and egress traffic respectively. This feature adds the support of applying such output policy-map on an SVI( Switch Virtual Interface ).
- Written by Josh Pfosi
- Posted on 10月 16, 2025
- Updated on 4月 6, 2026
- 5540 Views
SWitch Aggregation Group (SWAG) is a feature in EOS that supports combining multiple physical switches into a single, powerful virtual switch, simplifying network management and increasing scalability. This document describes how to configure and troubleshoot a SWAG.
- Written by Prasanna Parthasarathy
- Posted on 12月 23, 2021
- Updated on 4月 20, 2026
- 25578 Views
SwitchApp is an FPGA-based feature available on compatible Arista 7130 devices. It performs ultra low latency Ethernet packet switching. Its packet switching feature set, port count, and port to port latency are a function of the selected SwitchApp profile. Detailed latency measurements are available in the user guide on the Arista Support site.
- Written by Charlotte Fedderly
- Posted on 1月 21, 2019
- Updated on 1月 6, 2026
- 10880 Views
This article describes the TAP Aggregation 802.1Q (VLAN) tag stripping feature. This feature allows up to two of the outermost incoming 802.1Q tags to be stripped, and can be configured on a traffic steering policy or a tool port.
- Written by Vipul Shah
- Posted on 8月 27, 2019
- Updated on 1月 20, 2026
- 10317 Views
BGP routing information often contains more than one path to the same destination network. The BGP best-path selection algorithm determines which of these paths should be considered as the best path to that network
- Written by Baptiste Covolato
- Posted on 1月 13, 2026
- Updated on 1月 13, 2026
- 986 Views
Secure boot is a security feature available in Aboot (Arista bootloader) that verifies the cryptographic signature of the EOS SWI (software image) before it is booted. Aboot embeds certificates that allow it to recognize and validate official EOS releases from Arista. If the signature verification is successful, the secure boot check passes and Aboot proceeds to boot the SWI. If the signature verification fails, the boot is aborted.
- Written by Liviu Ivan
- Posted on 1月 6, 2026
- Updated on 1月 13, 2026
- 900 Views
TX queue precision shaping allows improving accuracy of observed shape rates on interfaces relative to configured values, in particular when the configured rate is low.
- Written by Gary McCarthy
- Posted on 6月 29, 2020
- Updated on 1月 16, 2026
- 12178 Views
Prior to EOS 4.24.1F, per-destination steering into an SR Policy was only supported for IP unicast BGP routes in the default VRF.
- Written by Mateusz
- Posted on 1月 8, 2026
- Updated on 1月 13, 2026
- 703 Views
This guide details how to use Zero Touch Provisioning (ZTP) on Arista switches.
- Written by Keerthana Parthasarathy
- Posted on 3月 4, 2025
- Updated on 3月 12, 2026
- 4602 Views
Support for matching of DSCP,ECN,VLAN is available under the QOS class-map configuration on Arista switches.
