• Tag : routing


RIB route control: next hop resolution policy

Description RIB Route Control is a collection of mechanisms for controlling how IP routing table entries get used. Next hop resolution policy adds support for preventing recursive resolution of next hops based on route map evaluation of resolving routes. Platform compatibility Next hop resolution policy is a platform independent feature. Configuration Next hop resolution policy is configured for a particular VRF with the rib ipv4|6 resolution policy command under router general. Arista(config)#router general Arista(config-router-general)#vrf default Arista(config-router-general-vrf-default)#rib ipv4 resolution policy MAP1 Dependant routes whose resolving route is permitted by the route map will be recursively resolved, and dependant routes whose resolving route is denied...
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ribd vs multi-agent (ArBGP)

My organization is developing lab scenarios to move our network towards implementing EVPN. Part of that process is to add the: service routing protocols model multi-agent command. We have found a few unique situations where the default behavior of routing (outside of BGP) has changed. For example: OSPF summary routes not working Static routes to unreachable next hops (while the interface is up) are not placed in the RIB. I have been unable to find any documentation outside about what actually changes when implementing that command. Is there a white paper about it, or a list of default behaviors that...
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1 or many vlan interface

Hi – new to Arista, first time setting them up. I’m using a 7020R effectively as an access layer device, 2x 10Gb in a port-channel to our core device. My question is related to static ipv4 routing on the 7020R. I have tried 2 approaches and they both seem to work with next to no testing. 1) Using a single vlan interface on the 7020R, assigning an ipv4 address, this creates a ‘Connected’ route then using static routes to point everything to the single vlan interface. Or… 2) Using a vlan interface per vlan, assigning each an ipv4 address and,...
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VXLAN Indirect Routing on 7280E, 7280R and 7500R series

In EOS-4.18.0F, VXLAN direct routing was introduced on the 7500R and 7280E/R series platforms. VXLAN routing provides the capability to route between VXLAN Layer 2 domains. In EOS-4.18.1, support for VXLAN Indirect Routing model is added to the 7500R and 7280E/R series platforms. In the Indirect routing model, the destination host is not directly attached to the VTEP(s) where the default gateway functionality is present. This model is called “indirect” because, in this model,  the packet possibly needs to go through multiple hops in the overlay to reach the final destination. It typically involves running routing protocols in the overlay...
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Overlay IPv6 routing over VXLAN

Overlay IPv6 routing over VXLAN Tunnel is simply routing IPv6 packets in and out of VXLAN Tunnels, similar to VXLAN overlay IPv4 routing. Underlay ( Outer IP Header ) in VXLAN still uses IPv4, and common for both overlay IPv4 and IPv6 . Hence VXLAN configuration remains exactly same for both IPv4 and IPv6 overlay routing support. This feature enables IPv6 networks/hosts get connected through VXLAN Tunnels. Following figure illustrates IPv6 routing followed by VXLAN encapsulation to reach a remote host across the VXLAN tunnel.   Following figure illustrates VXLAN decapsulation and routing of an IPv6 packet. Platform compatibility DCS-7050X DCS-7060X DCS7260X DCS-7050X2 DCS-7250X DCS-7304 / DCS-7308 /...
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Arista EOS – BGP Selective Route Download

Today, various content provided through the Internet continues to grow exponentially. Content Providers have spent significant CapEx dollars for their infrastructure typically peering with multiple providers to give their customers the best experience possible. This classically calls for BGP peering between these providers and leveraging one provider as a transit with a default route. Given the fact that many views of the global Internet routing table show approximately 580,000 IPv4 prefixes and 20,000 IPv6 prefixes (December 2015), large expensive routers are traditionally used in this capacity. This is because traditional deployments in the past took all the routes in the...
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VXLAN Routing with MLAG

Introduction This document describes the operation and configuration of  VXLAN routing on an Arista platform in conjunction with MLAG for redundancy. The configuration and guidance within the document unless specifically noted is based on the platforms and EOS releases noted in the table below.   Arista’s Multi-Chassis LAG (MLAG) technology provides the ability to build a loop free active-active layer 2 topology. The technology operates by allowing two physical Arista switches to appear as a single logical switch (MLAG domain), third-party switches, servers or neighbouring Arista switches connect to the logical switch via a standard port-channel (static, passive or active)...
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How to route to external subnets from VXLAN subnets and vice-versa

Hi,   I was able to setup Vxlan between Host1 and Host2 which are in Vlan 600 subnet Host1 and Host2 are able to reach each other via Vxlan. However, I want to know how do I setup the routing to external hosts outside the subnet? Below are the configs for both VTEPS. VTEP1 switch has a network that Host2 is trying to reach. Thank you VTEP1 (Switch1): spanning-tree mode mstp ! no aaa root ! vlan 492,600 ! interface Port-Channel2000 no switchport ip address ! interface Ethernet1 no switchport ip address ! interface Ethernet2 no switchport ip address...
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BGP METRIC attribute

Hi, I was trying to find out how do I configure Metric BGP attribute? I look all over the Arista commands and could not figure it out. Thank you   Victor

Programmatically update your routing table

Overview This article describes a script which is designed to allow the insertion/removal of a route in/from the routing table. If you want a way to remotely add/delete routes to/from your routing table, then this is the tool for you – using it will make insertion/removal of static routes as easy as running a script on any remote device that supports Python. How to get the code: Download the code Use your Github account and fork it (remember to contribute back) Installation The script (updateRoute) can be run/installed on any device that runs Python 2.7 or later. In order to run updateRoute, first...
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