--- title: IBGP Load Balancing with BGP Link Bandwidth « BGP Labs description: A hands-on BGP lab exercise covering IBGP unequal-cost multipathing (UCMP) using the BGP Link Bandwidth extended community. The lab walks through configuring... canonical: https://daily.dev/posts/ibgp-load-balancing-with-bgp-link-bandwidth-bgp-labs-xxzl45t5h twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: IBGP Load Balancing with BGP Link Bandwidth « BGP Labs | daily.dev og:description: A hands-on BGP lab exercise covering IBGP unequal-cost multipathing (UCMP) using the BGP Link Bandwidth extended community. The lab walks through configuring... og:url: https://daily.dev/posts/ibgp-load-balancing-with-bgp-link-bandwidth-bgp-labs-xxzl45t5h og:image: https://api.daily.dev/og/posts/xxZL45t5h.png og:image:alt: IBGP Load Balancing with BGP Link Bandwidth « BGP Labs 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. # IBGP Load Balancing with BGP Link Bandwidth « BGP Labs **[ipSpace.net Blog](https://daily.dev/sources/ipspace)** · 6 min read · 0 upvotes · 0 comments ## Summary A hands-on BGP lab exercise covering IBGP unequal-cost multipathing (UCMP) using the BGP Link Bandwidth extended community. The lab walks through configuring WE1 and WE2 edge routers to attach Link Bandwidth communities to EBGP paths (10 Gbps and 4 Gbps respectively), propagating those communities over IBGP to a Core router, and enabling UCMP so the Core distributes traffic proportionally rather than equally. Verification steps show expected BGP table output and routing table weights (3/4 vs 1/4) on Arista cEOS. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Questions this post answers ### How do I propagate BGP Link Bandwidth community over IBGP so the core router can use it for UCMP? Extended community propagation must be explicitly configured between IBGP peers; without it, the Core router never receives the Link Bandwidth community attached by edge routers. On some platforms, you must also specifically enable propagation of the BGP Link Bandwidth community type. Once propagated, the Core router can use the bandwidth values to compute unequal traffic weights — for example, 3/4 toward a 20 Gbps path and 1/4 toward a 4 Gbps path. _Engineers tuning BGP traffic engineering across an AS track implementation quirks like these on daily.dev._ ### How does BGP Link Bandwidth UCMP traffic distribution appear in the routing table on Arista cEOS? On Arista cEOS, the routing table shows per-path weights reflecting the Link Bandwidth ratio. With one path carrying a 20 Gbps community and another carrying 4 Gbps, the output displays 'weight 3/4' for the higher-bandwidth path and 'weight 1/4' for the lower-bandwidth path under the same prefix entry. _Network engineers validating UCMP behavior across platforms find real device output comparisons on daily.dev._ ## Similar posts on daily.dev - [BGP-Free Core with SR-MPLS « ipSpace.net blog](https://daily.dev/posts/bgp-free-core-with-sr-mpls-ipspace-net-blog-h7kronzy3) · ipSpace.net Blog · 0 upvotes · 0 comments --- Tags: [#bgp](https://daily.dev/tags/bgp) [View this post on daily.dev](https://daily.dev/posts/ibgp-load-balancing-with-bgp-link-bandwidth-bgp-labs-xxzl45t5h) ```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":"IBGP Load Balancing with BGP Link Bandwidth « BGP Labs","url":"https://daily.dev/posts/ibgp-load-balancing-with-bgp-link-bandwidth-bgp-labs-xxzl45t5h","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/ibgp-load-balancing-with-bgp-link-bandwidth-bgp-labs-xxzl45t5h"},"datePublished":"2026-08-11T08:51:49.194Z","dateModified":"2026-08-11T08:52:54.886Z","description":"A hands-on BGP lab exercise covering IBGP unequal-cost multipathing (UCMP) using the BGP Link Bandwidth extended community. 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