Category : Tech Tips

Overview Multicast is a means of sending data from one source to many receivers.  To understand what one to many looks like no further than a TV streaming service and or a paging system which calls only certain phones.  Unlike broadcast which multicast may act like depending on the design, typically multicast packets are not meant for the whole network but to a set of end points for a specific group.  Sending to a group is achieved by sending data to a multicast IP whose range is from 224.0.0.1 to 239.255.255.255.   For data to flow from its publisher or source,...
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Introduction Quality of Service (QoS) is the ability to provide different priorities to different applications, users, or data flows, or to guarantee a certain level of performance to a data flow. QoS processes apply to traffic that flows through Ethernet ports and control planes. These processes can modify data fields (Class of Service (CoS) or Differentiated Services Code Point (DSCP)) or assign data streams to traffic classes for prioritised handling. In this document we will be implementing a basic enterprise QoS model. Consider the following topology for the following examples:   What do we want to achieve In this example,...
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What is DNS? The Domain Name Server (DNS) maps FQDN labels to IP addresses and provides addresses for network devices. How to install it on EOS switch? EOS has a pre-installed DNSmasq service that can be used as a lightweight DNS server. The switch can be used in the recursive mode to take the local and external requests and forward them to an upstream DNS server.  Each network requires at least one server to resolve addresses. The configuration file can list a maximum of three server addresses. Configuration Step 1: In EOS CLI configure a name-server: ip name-server vrf default...
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Arista switches have the capability to break out QSFP and OSFP interfaces to multiple lanes of smaller speeds. This can be very useful for high density deployments that require a minimal RU footprint by maximizing the ports available on various Arista platforms. With QSFP interfaces, whether it be for 40G or 100G speeds, these are implemented as 4 lanes that can be independently controlled & configured. With 40G interfaces, these interfaces can operate in 4x10G speeds and for 100G interfaces can operate in 4x25G or 2x50G speeds .        As an example, with the Arista 7280CR2A-30 switch which comes with 30...
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Objective The goal of this document is to guide you through the setup of CloudEOS in AWS and/or Azure using CloudVision as-a-Service and the Terraform CloudEOS examples in the Arista GitHub repository. Obtain a CloudVision as-a-Service Account Work with an Arista account team member to procure a CloudVision as-a-Service account. Download and Install Terraform From www.terraform.io, download Terraform 13 or above.  It is best to place the terraform binary file in the PATH of your workstation for ease of use. Download and Install Cloud Provider CLI For AWS Cloud Deployment For an AWS demonstration environment, download and install AWS CLI...
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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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Aggregate VoQ drops on 7280/7500 devices On 7280/7500 devices, the platform architecture uses Virtual Output Queuing (VoQ) between the ingress and egress chips to forward known unicast traffic. Whenever a packet is to be transmitted, the ingress chip requests for credit from the egress. Once the credits are issued/granted, the packet is dequeued to the egress chip. While the packets are awaiting the credit, they are enqueued on the ingress chip buffers, in the Virtual Output Queue (VoQ) for the corresponding egress port. Accordingly, in the output of “show interfaces counters queue detail” on these devices, we see two sections:...
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Supported Platforms The Route-Map ‘continue’ feature is supported on all platforms and is hence platform-independent. The support for this feature in Multi-agent model has been added since EOS-4.21.0, and the support for this feature in Single-agent model  is supported since EOS-4.10.2 Background of the default operation of a route-map A given route-map can have a number of sequence statements each of which contain optional match and/or set rules. When a route is advertised to a BGP neighbor or received from a BGP neighbor, that route is evaluated against each sequence statement of the route-map that’s applied to the concerned neighbor,...
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Description This article will talk about how to onboard a switch in CVP 2019.1.x/2020.1.x and will deep-dive into the process involved during the registration process. In addition, we will also include the troubleshooting steps that can be taken in case the registration process fails.  Platform compatibility This feature is supported on all platforms. Configuration On the Switch: To enable the onboarding process, we will need to first enable command-api on the switch so that the switch is able to communicate with CVP via eAPI. This can be done in the following way: Arista#configure Arista(config)#management api http-commands Arista(config-mgmt-api-http-cmds)#no shut Arista(config-mgmt-api-http-cmds)#show active...
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