For those who have forgotten how LSA's work between Area's, let us refresh your memory: Type 1 and 2 LSA's live within their own Areas to create the SPF Tree ABR's extract the Network / Subnet Mask information to create a Type 3 LSA which it then floods into the other Area (Summary LSA in … Continue reading OSPF: Route filtering between Areas (Inter-Area) configured and explained!
Only the NBMA and Ethernet segments will be used for quick demonstrations and clarity, unless R4 or R5 is needed for demonstration. Now the idea of a Prefix-List in comparison to an Access-List may be hard to follow, but I will try to explain it. An Access-List at its most specific (Extended) matches only on … Continue reading EIGRP: DEEP Dive into Prefix-List configurations, Access-list vs Prefix-list, using Prefix-Lists to Filter EIGRP routes with Distribute-Lists!
One thing that was lacking from Chris Bryants training that I found in the INE series is explanations between when to use OSPF Filter-list vs a Distribute-list. I have modified the network as reflected in the Topology so Area 34 will no longer be a stub, and Area 15 will only be an NSSA Area. … Continue reading OSPF: DEEP Dive – Distribute-List vs Filter-List, and reviewing Prefix-Lists as Filter-Lists use Prefixes to filter!
BGP Prefix lists are important for their high flexibility, support for incremental updates, and that writing BGP Prefix lists are much more efficient than writing ACL's that filter BGP updates as BGP tables can have much more content (thousands of entries) in them as compared to IGP's route tables. They have some similarities to ACL's … Continue reading Prefix-Lists and BGP, fundamentals and configuration explained, important behaviors and more to know for exam day!