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New Member

Multiarea ISIS

Hi all

Anyone have experience with Multiarea ISIS routing. We are doing this in a DCN environment and need to configure partition avoidance, but this does not work. Any help would be appreciated.

From the config below, if we lose full connectivity with our L1 adj. within area100, then AREA100 should not then be advertised into the L2 core. This is the bit that does not seem to work.

config snipit.

!

router isis L2BackBone

redistribute connected route-map CONNECTED-TO-ISIS

redistribute static ip route-map STATIC-TO-ISIS

passive-interface Loopback0

maximum-paths 6

net 39.840f.8000.0000.0000.0000.0010.0010.0255.0003.00

is-type level-2-only

log-adjacency-changes

partition avoidance

!

router isis AREA100

net 39.840f.8000.0000.0000.0000.0100.0010.0255.0003.00

is-type level-1

!

5 REPLIES
Silver

Re: Multiarea ISIS

You're config looks fine to me and should work. If your AREA 100 looses all it's L1 adjacencies, it is still advertiesed? What code are you running? Might be an IOS defect you are running into.

Regards,

Don

New Member

Re: Multiarea ISIS

yes, if AREA100 looses all it's L1 adjacencies, it is still advertised.

IOS is 122-6

Silver

Re: Multiarea ISIS

Doing a quick Defect search on Mulit-area and partition avoidance I did not see anything to lead me to believe this would be broken in your code (assuming you're running mainline)

Found CSCdv72514 (partition avoidance: should forward packets by L2 route if no L1 adj) but that was fixed in 122-4 so you should not be hitting this issue.

Also not seeing the interface configuration I do not know, but assume you know that only one interface is allowed to be in each L1 Area for your muli-area configuration.

Here is a link showing this:

http://www.cisco.com/univercd/cc/td/doc/product/software/ios120/120newft/120t/120t5/ismarea.htm#xtocid299085

Does "show CLNS neighbor" off of your Area100 interface show anything of interest?

Showing CLNS neighbor shows all Area100 with no adj?

If nothing of help is found, and if you've got Area100 only bound to one interface I would recommend you get with your Cisco support peronnel and have them file a defect on this.

Hope this helps,

Don

New Member

Re: Multiarea ISIS

Don

you say the following "only one interface is allowed to be in each L1 Area"

My understanding of this from the link you provided, is that an interface can only be part of one L1 area. Do you agreee?

i.e would it be possible for the following to be configured

interface FastEthernet0/0

clns router isis AREA100

!

interface Tunnel1

clns router isis AREA100

!

Silver

Re: Multiarea ISIS

Yes, I do agree. An interface can only be in one L1.

The sole reason I brought this up is that you can configure multiple interfaces, as you mentioned, to be in the same L1. This is not supported but can be configured.

I hope you are finding your problem with partition avoidance,

Regards,

Don

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