--- title: SR-MPLS over Unnumbered Interfaces « ipSpace.net blog description: A hands-on walkthrough of running SR-MPLS over unnumbered IPv4 point-to-point interfaces using IS-IS as the underlying routing protocol. The setup requires... canonical: https://daily.dev/posts/sr-mpls-over-unnumbered-interfaces-ipspace-net-blog-qotfeb0it twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: SR-MPLS over Unnumbered Interfaces « ipSpace.net blog | daily.dev og:description: A hands-on walkthrough of running SR-MPLS over unnumbered IPv4 point-to-point interfaces using IS-IS as the underlying routing protocol. The setup requires... og:url: https://daily.dev/posts/sr-mpls-over-unnumbered-interfaces-ipspace-net-blog-qotfeb0it og:image: https://api.daily.dev/og/posts/QotFeB0it.png og:image:alt: SR-MPLS over Unnumbered Interfaces « 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. # SR-MPLS over Unnumbered Interfaces « ipSpace.net blog **[ipSpace.net Blog](https://daily.dev/sources/ipspace)** · 4 min read · 0 upvotes · 0 comments ## Summary A hands-on walkthrough of running SR-MPLS over unnumbered IPv4 point-to-point interfaces using IS-IS as the underlying routing protocol. The setup requires only a single netlab topology change (setting addressing.p2p.ipv4: True), after which IS-IS LSPs advertise SR-MPLS TLVs including adjacency SIDs attached to IS Neighbor TLVs. The MPLS forwarding table is identical to a numbered IPv4 SR-MPLS setup, confirming full compatibility. The lab is reproducible via a GitHub Codespace with Arista cEOS containers. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Questions this post answers ### Does SR-MPLS work over unnumbered IPv4 interfaces with IS-IS? SR-MPLS works correctly over unnumbered IPv4 point-to-point interfaces when the underlying IS-IS implementation supports them. IS-IS LSPs still advertise SR-MPLS TLVs including adjacency SIDs attached to IS Neighbor TLVs, and prefix SIDs for all loopback addresses remain present. The MPLS forwarding table is identical to a numbered IPv4 SR-MPLS setup, with pop and swap operations functioning normally. _Network engineers validating SR-MPLS design choices find lab evidence like this on daily.dev._ ### What netlab configuration change is needed to use unnumbered IPv4 on point-to-point links? Setting 'addressing.p2p.ipv4: True' in the netlab topology file enables unnumbered IPv4 on point-to-point links. This single line is the only change required compared to a standard numbered IPv4 SR-MPLS topology, and the resulting IS-IS and MPLS behavior remains functionally equivalent. _Engineers building netlab SR topologies track configuration patterns like this on daily.dev._ ## Similar posts on daily.dev - [MPLS/VPN with SR-MPLS Core « ipSpace.net blog](https://daily.dev/posts/mpls-vpn-with-sr-mpls-core-ipspace-net-blog-nw3uwiphe) · ipSpace.net Blog · 0 upvotes · 0 comments - [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 - [Multivendor SR-MPLS « ipSpace.net blog](https://daily.dev/posts/multivendor-sr-mpls-ipspace-net-blog-qekokwduk) · ipSpace.net Blog · 0 upvotes · 0 comments - [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 --- [View this post on daily.dev](https://daily.dev/posts/sr-mpls-over-unnumbered-interfaces-ipspace-net-blog-qotfeb0it) ```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":"SR-MPLS over Unnumbered Interfaces « ipSpace.net blog","url":"https://daily.dev/posts/sr-mpls-over-unnumbered-interfaces-ipspace-net-blog-qotfeb0it","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/sr-mpls-over-unnumbered-interfaces-ipspace-net-blog-qotfeb0it"},"datePublished":"2026-08-11T08:53:59.347Z","dateModified":"2026-08-11T09:05:26.284Z","description":"A hands-on walkthrough of running SR-MPLS over unnumbered IPv4 point-to-point interfaces using IS-IS as the underlying routing protocol. 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