--- title: BGP Route Aggregation « BGP Labs | daily.dev description: A hands-on lab exercise covering BGP route aggregation (summarization). It walks through redistributing OSPF routes into BGP, configuring the aggregate-address... canonical: https://daily.dev/posts/bgp-route-aggregation-bgp-labs-8jlmfugyv twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: BGP Route Aggregation « BGP Labs | daily.dev og:description: A hands-on lab exercise covering BGP route aggregation (summarization). It walks through redistributing OSPF routes into BGP, configuring the aggregate-address... og:url: https://daily.dev/posts/bgp-route-aggregation-bgp-labs-8jlmfugyv og:image: https://api.daily.dev/og/posts/8JlmFUgyV.png og:image:alt: BGP Route Aggregation « 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. # BGP Route Aggregation « BGP Labs **[ipSpace.net Blog](https://daily.dev/sources/ipspace)** · 7 min read · 0 upvotes · 0 comments ## Summary A hands-on lab exercise covering BGP route aggregation (summarization). It walks through redistributing OSPF routes into BGP, configuring the aggregate-address command to advertise a summary prefix (10.42.42.0/24) only when more-specific prefixes exist, suppressing those more-specific prefixes using the summary-only option, and applying an outbound prefix filter to clean up unwanted loopback advertisements. The lab uses netlab with Arista EOS or FRRouting and includes automated validation steps. ## 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 suppress more specific prefixes when using BGP route aggregation? Add the summary-only option to the aggregate-address command. This marks the more-specific component prefixes as suppressed (shown with 's' in the BGP table) and prevents them from being advertised to neighbors. Only the aggregate prefix, e.g. 10.42.42.0/24, is propagated, while the component prefixes like 10.42.42.16/28 and 10.42.42.128/25 remain locally visible but are not sent out. _Network engineers tuning BGP advertisement policies track lab exercises and real-world BGP patterns on daily.dev._ ### Why does BGP only aggregate prefixes that are already in the BGP table? BGP route aggregation works by summarizing prefixes already present in the BGP table, not the IP routing table directly. If no component prefixes exist in the BGP table, no aggregate is generated. This is why OSPF routes must first be redistributed into BGP before the aggregate-address command can produce a summary prefix. _Developers and network engineers working through BGP redistribution challenges find relevant discussions 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: [#networking](https://daily.dev/tags/networking), [#bgp](https://daily.dev/tags/bgp) [View this post on daily.dev](https://daily.dev/posts/bgp-route-aggregation-bgp-labs-8jlmfugyv) ```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":"BGP Route Aggregation « BGP Labs","url":"https://daily.dev/posts/bgp-route-aggregation-bgp-labs-8jlmfugyv","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/bgp-route-aggregation-bgp-labs-8jlmfugyv"},"datePublished":"2026-08-11T08:54:47.539Z","dateModified":"2026-08-11T09:04:07.406Z","description":"A hands-on lab exercise covering BGP route aggregation (summarization). 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