Four Site Hub and Spoke Network Diagram

BFD over broadcast networks

Overview What is BFD? Bidirectional Forwarding Detection (BFD) as defined in RFCs 5880 and 5881 is a protocol to detect network faults between the forwarding planes of two network devices. It is designed as a low-overhead protocol that can run over media that may not have built-in failure detection, including Ethernet, tunnels, and MPLS LSPs. Multiple control plane protocols can subscribe to a BFD session to be notified when connectivity is interrupted. This can help with faster convergence after a failure, as the IGP(s) do not have to wait for a connectivity timeout in their protocol. ...

February 8, 2022 · 7 min · Jason Lavoie
[Mixed](https://pixabay.com/photos/legs-feet-different-mixed-standing-362182/) by [RyanMcGuire](https://pixabay.com/users/ryanmcguire-123690/) licensed under [CC0](https://creativecommons.org/publicdomain/zero/1.0/legalcode)

Network in OSPF database but not in routing table

I needed to troubleshoot a pesky OSPF issue on a new network. It turned out it was a simple fix, but had tripped up a couple other network engineers so I thought I’d lab it up and document the scenario. The problem The reported issue was that a network that was part of the OSPF process was not showing up in the routing table. Adjacencies between all routers were up and the network in question was shown in the OSPF database. ...

November 16, 2021 · 5 min · Jason Lavoie