![Ticket#11: BGP Neighbor Flap – Hold Timer Expiry Due to MTU Mismatch [CCNP Enterprise]](https://networkjourney.com/wp-content/uploads/2025/07/Ticket11_BGP-Neighbor-Flap-–-Hold-Timer-Expiry-Due-to-MTU-Mismatch_networkjourney-1.png)
Problem Summary An enterprise experienced intermittent BGP neighbor flaps between core and WAN routers. The problem began after a WAN upgrade to a new service provider with slightly different interface MTU defaults. Symptoms Observed Root Cause Analysis After deeper analysis using packet captures and interface […]
![BGP Prefix Filtering – Control What You Advertise and Accept [ CCNP ENTERPRISE ]_networkjourney](https://networkjourney.com/wp-content/uploads/2025/06/BGP-Prefix-Filtering-–-Control-What-You-Advertise-and-Accept-CCNP-ENTERPRISE-.png)
One small misstep in BGP advertisement can lead to a network disaster — and yes, it has happened to many top companies (some even made the news!). That’s why today, we’re talking about a life-saving skill: BGP Prefix Filtering. I still remember an incident where […]
![BGP Path Attributes Table – The Backbone of BGP Decisions [ CCNP ENTERPRISE ]](https://networkjourney.com/wp-content/uploads/2025/07/BGP-Path-Attributes-Table-–-The-Backbone-of-BGP-Decisions_networkjourney-1.png)
Back in my early networking days, I thought BGP worked like OSPF or EIGRP — throw in some networks, and magic happens. But as I dug deeper, I realized BGP is a policy-based routing protocol, not just metric-based. And at the heart of this policy […]
![Mastering BGP Peering and Authentication – A Complete Guide [ CCNP ENTERPRISE ]_networkjourney](https://networkjourney.com/wp-content/uploads/2025/06/Mastering-BGP-Peering-and-Authentication-–-A-Complete-Guide.png)
When I first started working with BGP, I thought it was just about connecting two routers and typing in some IP addresses. But oh boy, did I underestimate it! Real-world BGP is like dealing with diplomatic foreign policies—every move matters, every configuration can make or […]
