There are three types of OSPF authentication. Type 1 – no authenticationType 2 – clear textType 3 – cryptographic (MD5 or SHA) Lets explore each type in a lot more detail and then look at the router configuration for some real world examples. Authentication can be configured on a per area or per interface, but […]
How to read and understand the OSPF Database
Just a quick post to point you all over to a fantastic resource on How to Read and Understand the OSPF Database Written by Alfred Lumbis who I believe is a Cisco employee it goes through step by step what you need to do to fully understand the OSPF database Extract: OSPF, being a link-state […]
OSPF Anatomy of an Internet Routing Protocol
Following a recommendation from Brian Dennis on a recent INE Vseminar. I decided to purchase a book every network engineer should read. OSPF Anatomy of an Internet Routing Protocol by John T Moy, the man who wrote the RFC for OSPF. The RFC for OSPFv2 is here RFC2328 Although this book was written many years […]
CCIE Troubleshooting OSPF Hello Mismatch
Whilst reading the RFC for OSPFv2 – RFC 2328 I noticed an interesting sentence in section 10.5 about Receiving Hello Packets. The generic input processing of OSPF packets will have checked the validity of the IP header and the OSPF packet header. Next, the values of the Network Mask, Hello Interval, and Router Dead Interval fields […]
MPLS LDP router-id loopback0 Force
Whilst configuring an MPLS lab I came across the force option on the MPLS LDP router-id command and was not sure what it did? After reading the documentation I will now explain the MPLS LDP router-id process and the relevance of the Force option. How the LDP Router-ID is derived If the MPLS Router-ID command […]