--- title: EVPN Designs: EVPN IBGP over IPv4 EBGP « ipSpace.net blog description: This post concludes a series on EVPN designs by examining the 'EVPN IBGP over IPv4 EBGP' pattern promoted by some networking vendors. The design runs IBGP... canonical: https://daily.dev/posts/evpn-designs-evpn-ibgp-over-ipv4-ebgp-ipspace-net-blog-iw5tx2ct1 twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: EVPN Designs: EVPN IBGP over IPv4 EBGP « ipSpace.net blog | daily.dev og:description: This post concludes a series on EVPN designs by examining the 'EVPN IBGP over IPv4 EBGP' pattern promoted by some networking vendors. The design runs IBGP... og:url: https://daily.dev/posts/evpn-designs-evpn-ibgp-over-ipv4-ebgp-ipspace-net-blog-iw5tx2ct1 og:image: https://api.daily.dev/og/posts/iw5tX2ct1.png og:image:alt: EVPN Designs: EVPN IBGP over IPv4 EBGP « ipSpace.net blog og:image:width: 1200 og:image:height: 630 og:locale: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # EVPN Designs: EVPN IBGP over IPv4 EBGP « ipSpace.net blog **[ipSpace.net Blog](https://daily.dev/sources/ipspace)** · 8 min read · 0 upvotes · 0 comments ## Summary This post concludes a series on EVPN designs by examining the 'EVPN IBGP over IPv4 EBGP' pattern promoted by some networking vendors. The design runs IBGP sessions (carrying EVPN address family) between loopbacks while using EBGP for the IPv4 underlay — achieved by exploiting BGP local AS functionality to make all routers appear to be in different autonomous systems for the underlay while remaining in the same AS for EVPN. The author provides a working netlab topology with Arista EOS and FRRouting configs, confirms the design functions correctly, but argues it is unnecessarily complex compared to simpler alternatives like IBGP-over-OSPF. The post concludes with a pointed critique: vendors pushing this design may be papering over product limitations rather than offering genuinely better architecture. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Questions this post answers ### How do you run EVPN IBGP sessions over an EBGP IPv4 underlay in a BGP-only fabric? All routers share the same BGP AS, making loopback-to-loopback sessions IBGP (used for EVPN). On the physical underlay links, each router uses BGP local AS to present a different AS number to its neighbor, making those sessions appear as EBGP. IPv4 unicast is activated only on the EBGP underlay sessions, while EVPN runs over the IBGP loopback sessions. Spines act as route reflectors for EVPN. _Network engineers weighing EVPN fabric designs find real-world configs and trade-off discussions on daily.dev._ ### What is the BGP local AS trick used to mix IBGP and EBGP in the same fabric? BGP local AS lets a router advertise a different AS number on a specific session without changing its global AS. In an EVPN IBGP-over-EBGP design, every router keeps the same global AS (e.g., 65000) for IBGP/EVPN, but each leaf uses a unique local AS (e.g., 65101) and spines use another (e.g., 65200) on underlay links, making those links behave as EBGP sessions for IPv4 reachability. _Keeping up with BGP fabric design patterns and vendor recommendations is easier when the right discussions surface on daily.dev._ ## Similar posts on daily.dev - [EVPN with SR-MPLS Core « ipSpace.net blog](https://daily.dev/posts/evpn-with-sr-mpls-core-ipspace-net-blog-taobtibzc) · ipSpace.net Blog · 0 upvotes · 0 comments --- Tags: [#bgp](https://daily.dev/tags/bgp) [View this post on daily.dev](https://daily.dev/posts/evpn-designs-evpn-ibgp-over-ipv4-ebgp-ipspace-net-blog-iw5tx2ct1) ```json {"@context":"https://schema.org","@graph":[{"@type":"Organization","@id":"https://daily.dev/#organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180},"sameAs":["https://twitter.com/dailydotdev","https://github.com/dailydotdev","https://www.linkedin.com/company/daily-dev-ltd"]},{"@type":"WebSite","@id":"https://daily.dev/#website","url":"https://daily.dev","name":"daily.dev","publisher":{"@id":"https://daily.dev/#organization"},"potentialAction":{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https://daily.dev/search?q={search_term_string}"},"query-input":"required name=search_term_string"}}]} {"@context":"https://schema.org","@type":"TechArticle","headline":"EVPN Designs: EVPN IBGP over IPv4 EBGP « ipSpace.net blog","url":"https://daily.dev/posts/evpn-designs-evpn-ibgp-over-ipv4-ebgp-ipspace-net-blog-iw5tx2ct1","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/evpn-designs-evpn-ibgp-over-ipv4-ebgp-ipspace-net-blog-iw5tx2ct1"},"datePublished":"2026-08-11T08:51:54.221Z","dateModified":"2026-08-11T08:56:51.095Z","description":"This post concludes a series on EVPN designs by examining the 'EVPN IBGP over IPv4 EBGP' pattern promoted by some networking vendors. 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