AristaConfig714 downloads

Arista EOS VLAN & Switchport Config

VLAN database, SVI interfaces with VRRP, trunk and access switchport configuration for Arista switches running EOS.

What is it?

Arista EOS VLAN configuration uses Cisco IOS-compatible syntax — VLAN IDs, SVI interfaces (Vlan100), trunk/access port modes. The key difference is VRRP (Virtual Router Redundancy Protocol) for gateway redundancy on SVIs — Arista supports both VRRP and its own MLAG active-active model. In MLAG deployments, both switches share the same SVI IP (via MLAG IP sharing) so VRRP is not needed. For standalone or non-MLAG deployments, VRRP provides first-hop redundancy with a virtual gateway IP.

When to use

·Access and distribution layer VLAN segmentation on Arista EX/DCS switches
·Inter-VLAN routing with SVI gateways (replacing a separate router)
·Adding VRRP for gateway redundancy when two distribution switches serve the same VLANs

When NOT to use

·MLAG data center deployments — use MLAG IP sharing instead of VRRP; both switches can be active gateways simultaneously without VRRP

How it compares

vs Cisco IOS VLANsSyntax is nearly identical — Arista was designed to be IOS-compatible. Main difference: Arista uses MLAG for active-active redundancy; Cisco uses vPC. Both support VRRP for first-hop redundancy.

vs Juniper EX VLANsJuniper uses IRB interfaces and 'family ethernet-switching'. Arista uses the familiar Cisco 'interface Vlan X' SVI syntax. Arista is easier to transition to from a Cisco background.

Prerequisites

→Management VRF and base config should be in place before adding VLANs
→VLAN IDs agreed with upstream switches before configuration
→VRRP virtual IP must not conflict with any physical interface IP or host address
→For MLAG deployments: configure MLAG before adding VLANs to ensure consistency between peers

Config Generator

Hostname *

VLANs

Trunk Interfaces

Access Ports

Verification commands

show vlan

Show all VLANs, names, and member interfaces

ExpectedLists VLANs with status 'active' and member interfaces. 'Inactive' VLANs have no active ports.

show interfaces Vlan<id>

Verify SVI interface is up and has correct IP

ExpectedProtocol should be 'up'. If 'down', no active ports are in the VLAN.

show vrrp

Show VRRP state for all SVIs with VRRP configured

ExpectedMaster shows 'Master', backup shows 'Backup'. Both should show the virtual IP.

Debug commands

show interfaces trunk

Show trunk port status and which VLANs are actually passing

Common mistakes & fixes

SymptomSVI interface shows 'protocol down'

CauseNo active physical ports belong to the VLAN

FixAt least one access or trunk port in the VLAN must be 'up' for the SVI to come up. Verify 'show vlan <id>' shows active member ports.

SymptomVRRP not electing a master — both show 'Init'

CauseVRRP hellos not reaching the peer (trunk not carrying the VLAN between switches)

FixVerify the VLAN is in the allowed list on the inter-switch trunk. Check 'show interfaces trunk' for VLAN in forwarding state.

Further learning

Recommended books to go deeper on this topic.

CCNA 200-301 Official Cert Guide Library

Wendell Odom · Cisco Press · VLANs, trunk ports, DTP, VTP, inter-VLAN routing

Kindle ↗Hardcover ↗

CCNP Enterprise Core ENCOR 350-401 Official Cert Guide

Brad Edgeworth et al. · Cisco Press · Advanced switching — STP, RSTP, MST, PVST+