--- title: Arista EOS MPLS P/PE-router Behavior « ipSpace.net blog description: An investigation into Arista EOS MPLS forwarding behavior reveals a key difference from Cisco IOS: Arista EOS only performs MPLS encapsulation for BGP... canonical: https://daily.dev/posts/arista-eos-mpls-p-pe-router-behavior-ipspace-net-blog-aqohezhvd twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: Arista EOS MPLS P/PE-router Behavior « ipSpace.net blog | daily.dev og:description: An investigation into Arista EOS MPLS forwarding behavior reveals a key difference from Cisco IOS: Arista EOS only performs MPLS encapsulation for BGP... og:url: https://daily.dev/posts/arista-eos-mpls-p-pe-router-behavior-ipspace-net-blog-aqohezhvd og:image: https://api.daily.dev/og/posts/aqOHeZHvd.png og:image:alt: Arista EOS MPLS P/PE-router Behavior « 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. # Arista EOS MPLS P/PE-router Behavior « ipSpace.net blog **[ipSpace.net Blog](https://daily.dev/sources/ipspace)** · 4 min read · 0 upvotes · 0 comments ## Summary An investigation into Arista EOS MPLS forwarding behavior reveals a key difference from Cisco IOS: Arista EOS only performs MPLS encapsulation for BGP destinations, not for IGP destinations. This means that in a BGP-free core, IGP-learned prefixes are forwarded without MPLS labels even when valid LDP bindings exist. The post also documents two other quirks: internal VLANs appearing in LFIB output for routed Layer-3 interfaces, and label allocation ranges that differ between devices depending on whether BGP was configured before LDP — since both protocols share the same dynamic label pool and BGP gets priority. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Questions this post answers ### Does Arista EOS apply MPLS labels to IGP routes when LDP bindings exist? No. Arista EOS performs MPLS encapsulation only for BGP destinations, not for IGP-learned routes, even when valid LDP bindings exist for those prefixes. This differs from Cisco IOS, which uses MPLS encapsulation for all prefixes with known LDP bindings from downstream routers. The IP routing table shows IGP routes forwarded without an LDP tunnel, while BGP routes explicitly reference an LDP tunnel index. _Engineers building MPLS cores with Arista EOS track vendor-specific forwarding quirks like this on daily.dev._ ### Why do LDP and BGP get different label ranges on Arista EOS and how does configuration order affect it? On Arista EOS, LDP gets the lowest dynamic label range unless BGP was configured first. If BGP is configured before LDP, BGP occupies the lower dynamic range (e.g., 100000–116383) and LDP gets the next block (e.g., 116384–132767). Both protocols share the same dynamic allocation pool, so using the mpls label range command does not resolve the discrepancy between peers. _Networking engineers sorting out Arista label allocation edge cases find peer discussions and vendor comparisons on daily.dev._ ## Similar posts on daily.dev - [Multivendor SR-MPLS « ipSpace.net blog](https://daily.dev/posts/multivendor-sr-mpls-ipspace-net-blog-qekokwduk) · 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 - [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 - [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 - [Arista cEOS Does Not Apply ACLs to Control-Plane Traffic « ipSpace.net blog](https://daily.dev/posts/arista-ceos-does-not-apply-acls-to-control-plane-traffic-ipspace-net-blog-ieh2uzhm7) · ipSpace.net Blog · 0 upvotes · 0 comments --- Tags: [#bgp](https://daily.dev/tags/bgp) [View this post on daily.dev](https://daily.dev/posts/arista-eos-mpls-p-pe-router-behavior-ipspace-net-blog-aqohezhvd) ```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":"Arista EOS MPLS P/PE-router Behavior « ipSpace.net blog","url":"https://daily.dev/posts/arista-eos-mpls-p-pe-router-behavior-ipspace-net-blog-aqohezhvd","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/arista-eos-mpls-p-pe-router-behavior-ipspace-net-blog-aqohezhvd"},"datePublished":"2026-08-11T08:54:29.547Z","dateModified":"2026-08-11T09:11:46.581Z","description":"An investigation into Arista EOS MPLS forwarding behavior reveals a key difference from Cisco IOS: Arista EOS only performs MPLS encapsulation for BGP...","image":"https://media.daily.dev/image/upload/s--ZrL_HSsR--/f_auto/v1722860399/public/Placeholder%2006","thumbnailUrl":"https://media.daily.dev/image/upload/s--ZrL_HSsR--/f_auto/v1722860399/public/Placeholder%2006","isAccessibleForFree":true,"articleSection":"ipSpace.net Blog","inLanguage":"en","publisher":{"@type":"Organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180}},"author":{"@type":"Organization","name":"ipSpace.net Blog","logo":"https://media.daily.dev/image/upload/s--xS7E82MT--/f_auto,q_auto/v1786438303/logos/ipspace?_a=BAMAMicg0","url":"https://daily.dev/sources/ipspace"},"commentCount":0,"discussionUrl":"https://daily.dev/posts/arista-eos-mpls-p-pe-router-behavior-ipspace-net-blog-aqohezhvd","interactionStatistic":[{"@type":"InteractionCounter","interactionType":{"@type":"LikeAction"},"userInteractionCount":0},{"@type":"InteractionCounter","interactionType":{"@type":"CommentAction"},"userInteractionCount":0}],"keywords":"bgp","timeRequired":"PT4M"} {"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https://daily.dev"},{"@type":"ListItem","position":2,"name":"ipSpace.net Blog","item":"https://daily.dev/sources/ipspace"},{"@type":"ListItem","position":3,"name":"Arista EOS MPLS P/PE-router Behavior « ipSpace.net blog"}]} {"@context":"https://schema.org","@type":"FAQPage","@id":"https://daily.dev/posts/arista-eos-mpls-p-pe-router-behavior-ipspace-net-blog-aqohezhvd#faq","mainEntity":[{"@type":"Question","name":"Does Arista EOS apply MPLS labels to IGP routes when LDP bindings exist?","acceptedAnswer":{"@type":"Answer","text":"No. Arista EOS performs MPLS encapsulation only for BGP destinations, not for IGP-learned routes, even when valid LDP bindings exist for those prefixes. 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