--- title: MLAG Deep Dive: Dynamic MAC Learning « ipSpace.net blog description: A deep dive into dynamic MAC learning challenges within MLAG (Multi-Chassis Link Aggregation) clusters. When frames traverse the peer link between MLAG... canonical: https://daily.dev/posts/mlag-deep-dive-dynamic-mac-learning-ipspace-net-blog-euz2bwksx twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: MLAG Deep Dive: Dynamic MAC Learning « ipSpace.net blog | daily.dev og:description: A deep dive into dynamic MAC learning challenges within MLAG (Multi-Chassis Link Aggregation) clusters. When frames traverse the peer link between MLAG... og:url: https://daily.dev/posts/mlag-deep-dive-dynamic-mac-learning-ipspace-net-blog-euz2bwksx og:image: https://api.daily.dev/og/posts/EUZ2BWKsx.png og:image:alt: MLAG Deep Dive: Dynamic MAC Learning « 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. # MLAG Deep Dive: Dynamic MAC Learning « ipSpace.net blog **[ipSpace.net Blog](https://daily.dev/sources/ipspace)** · 3 min read · 0 upvotes · 0 comments ## Summary A deep dive into dynamic MAC learning challenges within MLAG (Multi-Chassis Link Aggregation) clusters. When frames traverse the peer link between MLAG switches, traditional MAC learning causes incorrect forwarding decisions that violate hot-potato switching expectations. The post explains why MLAG switches cannot rely solely on dynamic MAC learning and must use a control-plane protocol to exchange MAC reachability. It also notes that ICCP (RFC 7275) alone is insufficient and must be combined with a protocol like EVPN. Three approaches to reconciling dynamic MAC learning with control-plane protocols are outlined: address source priority schemes, proprietary peer-link encapsulation hints, and disabling dynamic MAC learning on the peer link entirely. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Questions this post answers ### Why can't MLAG switches rely on dynamic MAC learning alone for forwarding decisions? When a frame from host A arrives at switch S2 and is forwarded over the peer link to S1, S1's dynamic MAC learning incorrectly records A as reachable via the peer link rather than the direct LAG member link. This breaks hot-potato switching. Additionally, if A uses both LAG members simultaneously, S1 sees the same source MAC from two ports, triggering duplicate MAC address alerts. _Network engineers designing MLAG fabrics track control-plane protocol choices like these on daily.dev._ ### Does ICCP (RFC 7275) handle MAC address advertisement between MLAG peers? ICCP (RFC 7275) does not provide MAC address advertisement functionality between MLAG cluster members. To build a standards-based MLAG solution that properly distributes MAC reachability, ICCP must be combined with another control-plane protocol such as EVPN. _Engineers evaluating standards-based MLAG designs find protocol comparisons like this on daily.dev._ --- [View this post on daily.dev](https://daily.dev/posts/mlag-deep-dive-dynamic-mac-learning-ipspace-net-blog-euz2bwksx) ```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":"MLAG Deep Dive: Dynamic MAC Learning « ipSpace.net blog","url":"https://daily.dev/posts/mlag-deep-dive-dynamic-mac-learning-ipspace-net-blog-euz2bwksx","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/mlag-deep-dive-dynamic-mac-learning-ipspace-net-blog-euz2bwksx"},"datePublished":"2026-08-11T08:52:51.107Z","dateModified":"2026-08-11T08:57:40.962Z","description":"A deep dive into dynamic MAC learning challenges within MLAG (Multi-Chassis Link Aggregation) clusters. 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