[j-nsp] isis adjacencies and isis database entries

snort bsd snortbsd at yahoo.com.au
Fri Mar 28 17:35:36 EDT 2008

from r2:

user at r2> show configuration protocols isis 
lsp-lifetime 65535;
level 2 {

interface ge-0/0/0.0 {
    level 1 disable;
    level 2 {
         hello-interval 10;


user at r2> show isis adjacency 
Interface             System         L State        Hold (secs) SNPA
ge-4/0/0.0            r1                2 Up                        24


user at r2> show isis database level 2 r2.00-00 detail        
IS-IS level 2 link-state database:

r2.00-00 Sequence: 0x5ad8, Checksum: 0xb90c, Lifetime: 65330 secs
   IS neighbor: r1.00                                   Metric:        10

----- Original Message ----
From: Stefan Fouant <sfouant at gmail.com>
To: snort bsd <snortbsd at yahoo.com.au>
Cc: juniper-nsp <juniper-nsp at puck.nether.net>
Sent: Friday, 28 March, 2008 2:06:33 PM
Subject: Re: [j-nsp] isis adjacencies and isis database entries

On Fri, Mar 28, 2008 at 4:25 PM, snort bsd <snortbsd at yahoo.com.au> wrote:
On r1, r2 is in list of "show isis adjacency". with the help of traceoptions under "protocols isis" (r1), I can see LSPs (other routers) coming via the interface (connecting to r2). Obviously r2 is advertising LSPs via this link.

You are seeing LSPs coming from the other routers coming via the interface connected to r2 because r2 is flooding out the LSPs it is receiving from those routers.  By no means should this be an indication that r2 is advertising anything... it is simply propogating the information received.  This is the nature of link-state protocols.
What I am getting at is that r2 might not be configured to advertise anything, hence you see nothing in the IS-IS database for r2, even though you have an established adjacency.  There is not necessarily a direct one-to-one correlation between adjacencies and database information.
What is interesting to me is that even if r2 has no export policy to export any routing information into IS-IS, I would surely expect to see it advertising the direct interface routes for the interfaces on which IS-IS is explicitly configured.
Can you access r2?  Let us see the contents of your protocols isis stanza on r2.


Stefan Fouant

      Get the name you always wanted with the new y7mail email address. www.yahoo7.com.au/y7mail

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