BGP Path Selection – Understanding “BGP Prefers the Path with the Lowest IGP Metric” So far in our BGP Best Path Selection series, we have explored several decision-making rules that BGP follows- Weight Local Preference Locally Originated AS Path Origin Code MED BGP Prefer eBGP over iBGP Now, it’s time to move to the next … Read more
Learn why BGP prefers eBGP routes over iBGP when all attributes are equal. This blog explains the concept with an easy topology, configuration, and clarification on the AD vs path selection confusion. In the previous blogs, we explored several BGP path selection attributes like Weight Local Preference Locally Originated AS Path Origin Code MED Each … Read more
Learn how BGP selects the best path using the ‘Originated Locally’ attribute. Understand route origination via network, redistribution, and aggregate commands with examples, configuration, and verification to simplify BGP path selection. When multiple routes exist to reach the same destination, BGP (Border Gateway Protocol) applies a step-by-step decision process to select the “best path.” Each … Read more
Learn how BGP Local Preference works in the path selection process. This step-by-step guide explains its role, configuration, and real-world examples to influence outbound traffic routing. In the previous blog, we explored the first BGP path selection attribute — Weight. Now, it’s time to move on to the second attribute in the decision process: Local … Read more
Understanding BGP Weight Attribute – The Complete Guide for Network Engineers The BGP weight attribute is a Cisco-proprietary value used to influence the best path selection process on a local router. It is a numeric value ranging from 0 to 65535, where paths with higher weight values are preferred. Importantly, this weight attribute is local … Read more
Learn BGP attributes and path selection in detail. Explore AS_PATH, LOCAL_PREF, MED, and more with examples, rules, and benefits for network optimization. Border Gateway Protocol (BGP) is the routing protocol that holds the internet together. Unlike protocols such as OSPF or EIGRP, which rely on metrics like cost or hop count, BGP makes routing decisions … Read more
Learn how BGP Allowas-in helps overcome eBGP routing loop issues in MPLS VPNs and multi-homed networks. Step-by-step lab, configs, and troubleshooting included. The Border Gateway Protocol (BGP) is the backbone of inter-domain communication, enabling autonomous systems (ASes) across the globe to exchange routing information. While BGP is robust and scalable, certain scenarios—especially in MPLS VPN … Read more
How BGP Prevents Loops in iBGP and eBGP: A Beginner-Friendly Guide with Scenarios When we talk about Border Gateway Protocol (BGP), we’re really talking about the glue that holds the internet together. BGP decides how traffic flows between massive networks called Autonomous Systems (AS). But here’s the catch: with so many routers exchanging routes, what … Read more
BGP Messages Explained: A Beginner-Friendly Guide If you’ve ever wondered “How does the internet know where to send my data?”, the answer is a protocol called BGP (Border Gateway Protocol). Think of BGP as the GPS system of the internet. It helps your data find the best and most reliable path to its destination. But … Read more
If you’ve ever typed show ip bgp summary and noticed your BGP neighbor sitting in Active or Connect, you might have wondered: “Why does BGP go through so many steps before finally exchanging routes?” You’re not alone — almost every network engineer has stared at these states at some point and scratched their head.The truth … Read more