--- title: Improve BGP Startup Time on Cisco IOS « ipSpace.net blog description: Cisco IOS release 15.x has a default `bgp update-delay` of 120 seconds, which causes BGP to wait for neighbors to finish sending updates before selecting best... canonical: https://daily.dev/posts/improve-bgp-startup-time-on-cisco-ios-ipspace-net-blog-vicvorvk9 twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: Improve BGP Startup Time on Cisco IOS « ipSpace.net blog | daily.dev og:description: Cisco IOS release 15.x has a default `bgp update-delay` of 120 seconds, which causes BGP to wait for neighbors to finish sending updates before selecting best... og:url: https://daily.dev/posts/improve-bgp-startup-time-on-cisco-ios-ipspace-net-blog-vicvorvk9 og:image: https://api.daily.dev/og/posts/viCVORVk9.png og:image:alt: Improve BGP Startup Time on Cisco IOS « 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. # Improve BGP Startup Time on Cisco IOS « ipSpace.net blog **[ipSpace.net Blog](https://daily.dev/sources/ipspace)** · 3 min read · 0 upvotes · 0 comments ## Summary Cisco IOS release 15.x has a default `bgp update-delay` of 120 seconds, which causes BGP to wait for neighbors to finish sending updates before selecting best paths and advertising routes. In virtual lab environments where all routers start simultaneously, this causes every router to wait for the others, stalling convergence until the timer expires. Setting `bgp update-delay 5` in the netlab Cisco IOS BGP configuration template dramatically reduces startup time. The post warns against applying this change in production networks, where the delay serves a real purpose — preventing premature route advertisements and potential traffic blackholing in multihomed designs. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Questions this post answers ### What is the default value of bgp update-delay on Cisco IOS and what does it do? The default `bgp update-delay` on Cisco IOS is 120 seconds. During this period, BGP waits for neighbors to establish and send their initial updates before calculating best paths and advertising routes. This prevents wasted CPU cycles from selecting routes based on incomplete information, but in virtual labs where all routers start simultaneously, it causes all routers to stall until the timer expires. _Network engineers tuning BGP lab environments track knobs like these on daily.dev._ ### How do I speed up BGP convergence in a Cisco IOS virtual lab? Set `bgp update-delay 5` in the BGP configuration to reduce the startup wait from the default 120 seconds to 5 seconds. In lab environments where all routers start simultaneously, the default 120-second delay causes every router to wait for the others, blocking convergence. Reducing the timer to 5 seconds resolves this without meaningful risk in a non-production context. _Engineers running routing protocol labs find fixes like this faster when following networking topics on daily.dev._ ## Similar posts on daily.dev - [Exploring the BGP Neighbor CONNECT State « ipSpace.net blog](https://daily.dev/posts/exploring-the-bgp-neighbor-connect-state-ipspace-net-blog-q28k0i62x) · ipSpace.net Blog · 0 upvotes · 0 comments - [BGP zombies and excessive path hunting](https://daily.dev/posts/bgp-zombies-and-excessive-path-hunting-avroyozsw) · Cloudflare · 0 upvotes · 0 comments - [The Never-Ending IPv6 Loopback Prefix Saga « ipSpace.net blog](https://daily.dev/posts/the-never-ending-ipv6-loopback-prefix-saga-ipspace-net-blog-4nlhgh10l) · ipSpace.net Blog · 0 upvotes · 0 comments --- Tags: [#bgp](https://daily.dev/tags/bgp), [#networking](https://daily.dev/tags/networking) [View this post on daily.dev](https://daily.dev/posts/improve-bgp-startup-time-on-cisco-ios-ipspace-net-blog-vicvorvk9) ```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":"Improve BGP Startup Time on Cisco IOS « ipSpace.net blog","url":"https://daily.dev/posts/improve-bgp-startup-time-on-cisco-ios-ipspace-net-blog-vicvorvk9","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/improve-bgp-startup-time-on-cisco-ios-ipspace-net-blog-vicvorvk9"},"datePublished":"2026-08-11T08:53:11.872Z","dateModified":"2026-10-14T02:23:42.495Z","description":"Cisco IOS release 15.x has a default `bgp update-delay` of 120 seconds, which causes BGP to wait for neighbors to finish sending updates before selecting best...","image":"https://media.daily.dev/image/upload/s--58gMhC4P--/f_auto/v1722860399/public/Placeholder%2012","thumbnailUrl":"https://media.daily.dev/image/upload/s--58gMhC4P--/f_auto/v1722860399/public/Placeholder%2012","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/improve-bgp-startup-time-on-cisco-ios-ipspace-net-blog-vicvorvk9","interactionStatistic":[{"@type":"InteractionCounter","interactionType":{"@type":"LikeAction"},"userInteractionCount":0},{"@type":"InteractionCounter","interactionType":{"@type":"CommentAction"},"userInteractionCount":0}],"keywords":"bgp,networking","timeRequired":"PT3M"} {"@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":"Improve BGP Startup Time on Cisco IOS « ipSpace.net blog"}]} {"@context":"https://schema.org","@type":"FAQPage","@id":"https://daily.dev/posts/improve-bgp-startup-time-on-cisco-ios-ipspace-net-blog-vicvorvk9#faq","mainEntity":[{"@type":"Question","name":"What is the default value of bgp update-delay on Cisco IOS and what does it do?","acceptedAnswer":{"@type":"Answer","text":"The default `bgp update-delay` on Cisco IOS is 120 seconds. During this period, BGP waits for neighbors to establish and send their initial updates before calculating best paths and advertising routes. This prevents wasted CPU cycles from selecting routes based on incomplete information, but in virtual labs where all routers start simultaneously, it causes all routers to stall until the timer expires. Network engineers tuning BGP lab environments track knobs like these on daily.dev."}},{"@type":"Question","name":"How do I speed up BGP convergence in a Cisco IOS virtual lab?","acceptedAnswer":{"@type":"Answer","text":"Set `bgp update-delay 5` in the BGP configuration to reduce the startup wait from the default 120 seconds to 5 seconds. In lab environments where all routers start simultaneously, the default 120-second delay causes every router to wait for the others, blocking convergence. Reducing the timer to 5 seconds resolves this without meaningful risk in a non-production context. Engineers running routing protocol labs find fixes like this faster when following networking topics on daily.dev."}}]} ```