• Author : Kenneth Finnegan


Understanding Table Sizes on the 7050QX-32

A common question asked about Arista switches is “how many routes can they handle”, and unfortunately, this is never an easy question to answer. Dedicated switch ASIC hardware is required to program each route so that when a packet arrives with a certain destination address, the switch can look up the destination and route the packet to the correct interface at line-rate across all the ports. The part that makes it hard is that there is practically never a 1:1 mapping between hardware resources on a switch and the number of routes that can be programmed into them, and under...
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Standalone BGP Origin Validation with RPKI

The Border Gateway Protocol (BGP) is the primary routing protocol used between the tens of thousands of different networks that make up the global Internet. Unfortunately, the original conception of BGP presumed a fundamental level of trust between all of the participating networks, which has repeatedly permitted both major and minor outages across the Internet due to networks accepting incorrect routing information. Either deliberately or accidentally, networks are able to advertise more specific prefix routing information for address space controlled by other networks to their peers over BGP, which causes that traffic to flow through their network instead of to...
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A Simple Quality of Service Design Example

While there is plenty of documentation available discussing the individual mechanics of Quality of Service, such as Class of Service (CoS) or Differentiated Services Code Point (DSCP) markings and what they mean, there is not as much documentation available bridging the gap from those basic building blocks to a working network QoS deployment. There are some understandable reasons for that lack of documentation, because the design and implementation of a QoS policy on a network is so closely coupled to the specific network’s business objectives and policies that it’s hard to develop much of a QoS policy and have it...
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Introduction to the Network Time Protocol

This document covers the use of the Network Time Protocol (NTP) to synchronize the system clocks on Arista switches. While each switch does have a local clock which can keep time without NTP, each device’s clock will slowly drift out of sync, causing issues including incorrect timestamps on event logs, which can make it difficult to correlate events between devices on the network, an inability to correctly verify the validity of cryptographic certificates for protocols such as TLS or DNSSEC, etc. EOS comes with support to act as both an NTP client and an NTP server; this document will only...
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