# EVPN Designs: Layer-3 Inter-AS Option A

DevFeed: [EVPN Designs: Layer-3 Inter-AS Option A](<https://devfeed.tech/articles/evpn-designs-layer-3-inter-as-option-a-11226.md>)

Original publisher: [Read original article](<https://blog.ipspace.net/2025/08/evpn-designs-interas-a/>)

Published: 2025-08-26T06:48:00Z

Content type: tutorial

Language: en

Sources: [ipSpace.net blog](<https://devfeed.tech/sources/ipspace-net-blog.md>)

Topics: [evpn](<https://devfeed.tech/topics/evpn.md>), [MPLS VPN](<https://devfeed.tech/topics/mpls-vpn.md>), [BGP](<https://devfeed.tech/topics/bgp.md>), [networking](<https://devfeed.tech/topics/networking.md>)

Tags: [bgp](<https://devfeed.tech/tags/bgp.md>), [design](<https://devfeed.tech/tags/design.md>), [evpn](<https://devfeed.tech/tags/evpn.md>), [evpn-designs](<https://devfeed.tech/tags/evpn-designs.md>), [mpls-vpn](<https://devfeed.tech/tags/mpls-vpn.md>), [netlab](<https://devfeed.tech/tags/netlab.md>), [routing](<https://devfeed.tech/tags/routing.md>), [vxlan](<https://devfeed.tech/tags/vxlan.md>)

## AI overview

This tutorial examines a multi-site design in which each site runs an independent EVPN fabric connected by a layer-3 DCI with a separate virtual link for each tenant, known as Inter-AS Option A in MPLS/VPN. It uses a netlab topology to show how EVPN type-2, type-3, and type-5 routes are propagated between sites through tenant VRF BGP sessions.

## Source excerpt

A netlab user wanted to explore a multi-site design where every site runs an independent EVPN fabric, and the inter-site link is either a layer-2 or a layer-3 interconnect (DCI). Let's start with the easiest scenario: a layer-3 DCI with a separate (virtual) link for every tenant (in the MPLS/VPN world, we'd call that Inter-AS Option A) Lab topology Read more ...