OSPF - INTRODUCTION TO LSA

Function, structure and types of LSA used by OSPF for the exchange of information

Loading video...

NOTE: You can only see a limited low resolution version of the video, if you want to view the full version please sign up and get any of our plans!

Video Description

LSA - Link State Advertisements

The way the routers communicate the topology information to each other
Using the information exchanged via LSAs, the Link-State Database is constructed

Depending on the topology, some LSA have a limited range
Initially, we'll focus on 6 types of LSA but there are actually 11 different LSA types defined

IPv4 Unicast Routing LSAs:
Type 1 - Router LSA : Limited to the area where they were generated. Generated by all of the routers. They describe each one of the links and networks on the area.

Type 2 - Network LSA: Limited to the area where they were generated. Generated by the DR. On the NBMA/Broadcast segments, lists all of the routers connected to the segment.

Type 3 - Summary LSA: Sent between areas. Generated by the ABR. They contain the summary information of the area (described via LSAs 1/2) to be sent to other areas. Removes topology details between areas and just describes the link ID/corresponding metric. 

Type 4 - ASBR Summary LSA: Sent between areas. Generated by the ABR. They provide summarized information on how to reach the ASBR outside of the area where they reside. 

Type 5 - External LSA: Sent between areas. Generated by the ASBR. They describe information regarding an external routing domain

Type 7 - NSSA  External LSA: Limited to the area where they were generated. Generated by the ASBR on NSSA areas. They describe information regarding an external routing domain in NSSA areas.

Rating

Global

Watch video in playlist

comments powered by Disqus