- Written by Bharath Somayaji
- Posted on September 30, 2015
- Updated on March 7, 2024
- 10515 Views
SPF Timers can be used in IS-IS to throttle the frequency of shortest-path-first (SPF) computations. In networks with a lot of churn, using these timers will help in containing the effect of network disruptions arising out of frequent SPF runs.
- Written by Ashish Yadav
- Posted on February 8, 2017
- Updated on February 9, 2017
- 9842 Views
The default behavior of a level 1 router running IS IS is to install a default route to a level 1 2 router present in a
- Written by Aditya Gujral
- Posted on September 30, 2015
- Updated on September 30, 2015
- 9872 Views
This feature adds Intermediate System to Intermediate System (IS IS) support for IP version 6 (IPv6) address family
- Written by Weichen Zhao
- Posted on August 25, 2016
- Updated on August 25, 2016
- 10263 Views
This feature provides a way to export non ISIS routes into level 1, level 2 or both by using route map's set clause. The
- Written by Aditya Gujral
- Posted on September 30, 2015
- Updated on February 7, 2022
- 9979 Views
This feature extends the IS IS set overload bit command to support wait for BGP option. In scenarios
- Written by Liam Smyth
- Posted on August 29, 2025
- Updated on August 29, 2025
- 1424 Views
Data entries from journald can be viewed through the CLI and the REST API. If the REST API is used the data is returned to the user in the form of a list of structured entries. This API is only for viewing journal data contained on the node being queried. The user is given the option to pass parameters to the API that can be used for pagination and for filtering the data that gets returned, e.g. only returning entries that were written by a specific application or after a specific start time.
- Written by Patrycja Kochmanska
- Posted on October 10, 2025
- Updated on October 10, 2025
- 1231 Views
The routing table is not available on the standby supervisor in EOS, hence running any diagnostics or scripts that talk to the standby supervisor through the forwarding plane is not possible. This feature adds a new Cli command that configures a default route on a standby supervisor. This default route will offload routing to the forwarding plane. Therefore it behaves the same way as the routing table on the active supervisor. The default route is installed on all VRFs.
- Written by Zeyad Tamimi
- Posted on March 3, 2023
- Updated on November 4, 2025
- 14350 Views
At a high level, L1 profiles are a set of configurations which allow EOS users to change the numbering scheme and default L1 configurations of all front panel interfaces across their network switch. On Arista network switches, front panel transceiver cages are exposed as ports which are numbered sequentially: 1, 2, 3, 4, etc. These identifiers are usually marked on the front panel to allow for easier identification.
- Written by Yiming Pan
- Posted on April 18, 2024
- Updated on April 1, 2025
- 7425 Views
Arista’s 7135 Connect Series of Layer 1+ switches are powerful network devices that allow for dynamic connections between various layer 1 components on the system, such as the front panel and FPGA. These connections are driven by an underlying CLOS network of crossbar switches. The following commands provide the ability to configure middle stage crossbar switches within the system to create dynamic layer 1 connections.
- Written by Shriprama Rao
- Posted on March 17, 2025
- Updated on March 17, 2025
- 3101 Views
This feature allows transport of multicast frames to an endpoint across an IP network by tunneling them through MPLSoGRE or MPLSoGUE. The tunneling of multicast frames is achieved with a traffic policy applied on the ingress interface which will match on all packets destined to a multicast IP address and redirect that traffic to a MoG nexthop group. The traffic policy will also specify “forced routing” in order to set the fwd_layer_index to 1 so that the L2 header is removed before encapsulation.
- Written by Prakrati Vidyarthi
- Posted on August 16, 2018
- Updated on January 20, 2026
- 22858 Views
Normally, a switch traps L2 protocol frames to the CPU. However, certain use-cases may require these frames to be forwarded or dropped. In cases where the L2 protocol frames are forwarded (eg: Pseudowire), we may require the frames to be trapped to the CPU or dropped. The L2 Protocol Forwarding feature provides a mechanism to control the behavior of L2 protocol frames received on a port or subinterface.
- Written by Ajay Chhatwal
- Posted on May 15, 2020
- Updated on December 9, 2025
- 13049 Views
L2 protocol frames - LLDP, LACP and STP are trapped to the CPU by default. This feature allows for disabling the per protocol trap on a given set of interfaces.
- Written by Ravi Krishnamurthy
- Posted on January 7, 2026
- Updated on January 7, 2026
- 533 Views
L2 support for CloudEOS and AWE is added.
- Written by Mihyar Baroudi
- Posted on December 8, 2015
- Updated on December 21, 2015
- 10219 Views
In our current implementation, on a switch with default startup config or no config, all ports come up in access
- Written by Sarah Chen
- Posted on October 17, 2024
- Updated on October 17, 2024
- 5160 Views
This feature is used to connect a Layer 3 EVPN VXLAN network to an Adaptive Virtual Topology (AVT) WAN network using dynamic path selection (DPS) tunnels. One or a pair of WAN routers are configured to serve as the VXLAN gateway. On the control plane, the configured VXLAN gateway handles EVPN IP-PREFIX route exchanges between the VXLAN network and the WAN network. On the data plane, the configured VXLAN gateway decapsulates the VXLAN packets received from the VXLAN network and encapsulates them into the DPS tunnels and sends them to the AVT WAN network.
- Written by Isidor Kouvelas
- Posted on December 22, 2017
- Updated on December 9, 2020
- 12710 Views
This feature is available when configuring BGP in the multi agent routing protocol model. Ethernet
- Written by Lavanya Conjeevaram
- Posted on June 29, 2016
- Updated on April 25, 2018
- 11262 Views
L3 interface ingress counters can be used to count routable traffic coming into the box on sub interfaces and vlan
- Written by Manuel Mendez
- Posted on September 30, 2019
- Updated on November 5, 2025
- 12894 Views
Subinterfaces divide a single ethernet or port channel interface into multiple logical L3 interfaces based on the 802.1q tag (VLAN ID) of incoming traffic. Subinterfaces are commonly used in the L2/L3 boundary device, but they can also be used to isolate traffic with 802.1q tags between L3 peers by assigning each subinterface to a different VRF. L3 subinterface shaping + VRF is also supported.
- Written by Jayden Navarro
- Posted on February 8, 2017
- Updated on February 15, 2017
- 10181 Views
LACP on Loopback Interfaces allows for Active Port Channels on one or more interfaces whose link endpoints terminate
- Written by Jayden Navarro
- Posted on February 8, 2017
- Updated on February 9, 2017
- 11196 Views
LACP State Transition Event Monitoring on Arista switches allows for quick and filterable viewing of LACP state
- Written by Nathan Wolfe
- Posted on February 15, 2018
- Updated on July 15, 2025
- 17627 Views
Introduced in EOS-4.20.1F, “selectable hashing fields” feature controls whether a certain header’s field is used in the hash calculation for LAG and ECMP.
- Written by Mihyar Baroudi
- Posted on February 1, 2016
- Updated on September 29, 2025
- 11625 Views
LAGs are allocated hardware resources on transition from one member (software LAG) to two members (hardware LAG) and deallocated hardware resources on transition from two member to one member. This allocation/deallocation causes some traffic disruption. Starting with EOS4.15.4F, the option to configure all LAGs to use hardware resources is supported on the 7500E platform.
- Written by Yuta Higuchi
- Posted on April 23, 2025
- Updated on April 23, 2025
- 2578 Views
This document addresses LAG hashing improvements across different platforms. In DANZ Monitoring Fabric (DMF) 8.7, the Controller applies the default hash configuration if no hash fields are configured or the configuration contains an error. If the Controller detects any hash error, DMF reports it as a fabric error.
- Written by Piotr Nowakowski
- Posted on December 20, 2024
- Updated on December 20, 2024
- 3905 Views
Switches can now use two LAG partitions (A and B) to support double the number of available Port Channels dictated by the chosen LAG mode. This is useful if the selected LAG mode does not allow the creation of the desired number of Port Channels on a single partition.
- Written by Greg Poloczek
- Posted on September 11, 2017
- Updated on September 11, 2017
- 11152 Views
Arista switches use the hashing algorithm to load balance traffic among LAG (Link Aggregation Group) members
- Written by Dawon Lee
- Posted on August 17, 2018
- Updated on October 16, 2025
- 13361 Views
LANZ Mirroring feature allows users to automatically mirror traffic queued as a result of congestion to either CPU or a different interface.
- Written by Stefan Rebaud
- Posted on March 31, 2017
- Updated on January 11, 2022
- 10910 Views
This document describes the current status of LANZ on DCS 7500R, DCS 7280R and DCS 7020R, for both polling and
- Written by Pinky Agrawal
- Posted on November 22, 2017
- Updated on December 22, 2017
- 9958 Views
LANZ on 7160S 32CQ, 7160 48YC6 and 7160 48TC6 adds support for monitoring congestion on front panel ports with Start,
- Written by Zackary Ayoun
- Posted on May 23, 2022
- Updated on February 5, 2026
- 15600 Views
LANZ is the EOS Latency and congestion ANalyZer. On DCS-7280, DCS-7020, DCS-7500 and DCS-7800 series, it allows monitoring congestion and transmit latencies on both front panel and CPU ports.
- Written by Tanuj Kumar Jhamb
- Posted on July 2, 2024
- Updated on November 4, 2025
- 6284 Views
ECN (Explicit Congestion Notification) is a mechanism of notifying network congestion without dropping the packets. The ECN based network congestion notification can be done in two ways: queue-length based ECN, latency based ECN. The queue-length based ECN marks the ECN-Capable Transport (ECT) packets when the average VOQ length exceeds the configured ECN threshold value whereas latency based ECN notify the congestion by marking the ECT packets, if packets take longer than the configured threshold to get dequeued from the VOQ. Both result in the egress marking of the packet if the congestion experienced is beyond the threshold.
- Written by Andrei Dvornic
- Posted on April 2, 2015
- Updated on January 20, 2026
- 17665 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 Diksha Mahajan
- Posted on March 3, 2023
- Updated on January 8, 2026
- 10441 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 Navneet Sinha
- Posted on June 29, 2016
- Updated on April 17, 2025
- 12136 Views
The Label Distribution Protocol (LDP) is a protocol in the Multiprotocol Label Switching (MPLS) context that allows label switch routers (LSRs) to exchange label mapping information. It is a distributed protocol without a central controller. Instead, each LSR generates local label mappings for Forward Equivalence Classes (FECs) and propagates this information to adjacent LSRs which it maintains LDP sessions with.
- Written by Shyam Kota
- Posted on June 5, 2020
- Updated on August 20, 2025
- 11677 Views
This feature implements RFC 3478. It allows devices to preserve the MPLS LDP LFIB entries in the forwarding plane if the TCP connection is lost or LDP agent restarts.
- Written by Pedro Coutinho
- Posted on December 22, 2020
- Updated on April 30, 2025
- 16505 Views
The LDP pseudowire feature provides support for emulating Ethernet connections over a Multiprotocol Label Switching (MPLS) network using the extension of the MPLS Label Distribution Protocol (LDP)
- Written by Xin Guang (Tony) Du
- Posted on August 25, 2016
- Updated on November 23, 2020
- 15172 Views
The LDP pseudowire feature provides support for emulating Ethernet connections over a Multiprotocol Label
- Written by Pavan Narasimhaprasad
- Posted on June 27, 2024
- Updated on September 4, 2025
- 5637 Views
Leaf Smart System Upgrade (SSU) provides the ability to upgrade the EOS image with minimal traffic disruption.Note: It is possible that SSU shutdown and bootup are not supported in the same image. If a product has shutdown support in image A and bootup support in a later image B, then SSU upgrade cannot be performed from image A to any images earlier than image B, including image A itself. However, upgrading from image A to image B onwards is allowed.
- Written by Girish Dasari
- Posted on April 30, 2025
- Updated on April 30, 2025
- 2818 Views
At a transit router when multiple LSP are available for a given destination from different protocols EOS does stitching based on hard coded preferences. LFIB stitching preferences give a provision to stitch together different LSPs based on configurable preferences. For each protocol(destination) preference can be configured for a given source protocol.
- Written by Michael Chin
- Posted on February 22, 2021
- Updated on December 20, 2024
- 12759 Views
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.
- Written by Sahil Midha
- Posted on December 22, 2017
- Updated on February 6, 2022
- 13873 Views
Link Fault Signalling (LFS) is a mechanism by which remote link faults are asserted over a link experiencing
- Written by Deepak Sebastian
- Posted on March 21, 2025
- Updated on March 21, 2025
- 3028 Views
This feature adds support for Layer1-only front panel Ethernet ports on 7130 devices (containing a layer1 crosspoint chip) to participate in LLDP. As of 4.33.1F only internal Switch interfaces on ASICs/FPGAs participate in the LLDP protocol. The neighbor also only sees these internal ports from the switch. Customers who really care about/rely on LLDP information of the front panel Ethernet ports, especially for making cabling changes, would need to translate the internal interface to the appropriate Ethernet port using the show l1 path output.
- Written by Dhruba Jyoti Pokhrel
- Posted on July 16, 2024
- Updated on July 16, 2024
- 4905 Views
Local Authentication (also known as authentication survivability) is the ability of access points (AP) to authenticate and onboard clients to the network using root CA certificates through the integrated EAP server of the AP. Use Local Authentication when the RADIUS servers are not reachable to authenticate the clients. It is typically a temporary authentication mechanism; avoid using it as a primary authentication. If there are certificate chains, you must upload the root CA certificate along with the certificate chain.
- Written by Kewei Shi
- Posted on November 4, 2020
- Updated on May 21, 2025
- 13953 Views
Logical ports are hardware resources that are required to activate interfaces.
- Written by Prachi Modi
- Posted on February 20, 2023
- Updated on February 20, 2023
- 7919 Views
With the 14.0 release, CloudVision Cognitive Unified Edge (CV-CUE) removes the Wireless Manager(WM) UI dependency for login and for applying the service license. You will no longer be redirected to WM and can now directly login to CV-CUE from the UI.
- Written by Nikos Kokkalis
- Posted on December 27, 2024
- Updated on November 3, 2025
- 4541 Views
The low latency tx-queue scheduler profile feature aims to provide an alternative operating mode for the queue that is fine-tuned for reduced latency. This involves a tradeoff between achieving lower latency and being able to sustain full throughput over a large number of flows.
- Written by Sidak Aneja
- Posted on April 30, 2025
- Updated on April 30, 2025
- 2698 Views
This TOI introduces a new global CLI configuration command to transition CMIS compliant transceivers to the low-power mode when all interfaces associated with the transceiver are shut down. Conversely, the transceivers will transition into high power mode when any interface associated with the transceiver is enabled.
- Written by Bin Wang
- Posted on December 22, 2020
- Updated on January 7, 2026
- 11737 Views
For various peering applications, there is a need to support the assignment of a MAC address on routed interfaces.
- Written by Vikas Hegde
- Posted on June 29, 2016
- Updated on February 8, 2022
- 11969 Views
Support for Media Access Control Security (MACsec) with static keys was added in EOS 4.15.4. This feature brings
- Written by Tarun Jaswanth LNU
- Posted on June 14, 2021
- Updated on June 2, 2025
- 13269 Views
Media Access Control Security (MACsec) is an industry standard encryption mechanism that protects all traffic
- Written by Jeff Chan
- Posted on June 16, 2022
- Updated on June 3, 2025
- 2688 Views
Media Access Control Security (MACSec) is an industry standard encryption mechanism to protect all traffic flowing on Ethernet links. Mac Security is described in IEEE 802.1X and IEEE 802.1AE standards.
