03-11-2012 08:46 AM - edited 03-07-2019 05:29 AM
I need to find out how changing Router's Levels on IS-IS network affects routing tables. I am having troubles finding any information about this on the internet. I was given an example network and told how the levels would change on it. I need to explain in theory how it would affect the routing tables. I would be very grateful if someone could explain me how the routing tables woudl change on the next network:
As default the routers are all on L1/L2 state. Now we would leave ROOPE TOUHO, TUPU and LEENU routers as L1/L2 and change all routers in areas 0002-0005 to L1. And finally the KROISOS router would be changed to L2. Now how would the routing tables change from the starting position where all the routers were L1/L2?
Picture of network attached
Solved! Go to Solution.
03-11-2012 10:08 AM
Hello Niko,
Key rule to remember: The routing table of an L1 router will contain routes only from the router's own area. An L1 router has no information about routes in other areas - instead, they will be represented by a default route pointing towards the nearest L1/2 router that has an active adjacency to a neighbor in different area. L1/2 and L2 routers will know routes from all areas in the routing domain.
The changes you will encounter:
Does this help a little? Please feel welcome to ask further!
Best regards,
Peter
P.S.: Is this a real network scenario or a school project?
03-11-2012 10:08 AM
Hello Niko,
Key rule to remember: The routing table of an L1 router will contain routes only from the router's own area. An L1 router has no information about routes in other areas - instead, they will be represented by a default route pointing towards the nearest L1/2 router that has an active adjacency to a neighbor in different area. L1/2 and L2 routers will know routes from all areas in the routing domain.
The changes you will encounter:
Does this help a little? Please feel welcome to ask further!
Best regards,
Peter
P.S.: Is this a real network scenario or a school project?
03-11-2012 11:04 AM
Thank you Peter, this helped me perfectly. Your answer cleared all my questions.
It is part of pre-study for school project we have next week with IS-IS.
Thank you again, you helped me a lot
Discover and save your favorite ideas. Come back to expert answers, step-by-step guides, recent topics, and more.
New here? Get started with these tips. How to use Community New member guide