ISIS Issue Route redistribution

[Toufiq-ur-Rehman]

Please find below the routers config and result.

ABR L1/L2Router:

root@PE4# show
## Last changed: 2010-07-24 01:05:17 UTC
version 8.5R1.14;
system {
    host-name PE4;
    root-authentication {
        encrypted-password "$1$2enfNnym$Egs1JdprjaMEzddrc21Ll1"; ## SECRET-DATA
    }
}
interfaces {
    em1 {
        unit 0 {
            family inet {
                address 10.0.2.10/30;
            }
            family iso;
        }
    }
    em2 {
        unit 0 {
            family inet {
                address 10.0.2.6/30;
            }
            family iso;
        }          
    }
    em4 {
        unit 0 {
            family inet {
                address 10.0.4.9/30;
            }
            family iso;
        }
    }
    lo0 {
        unit 0 {
            family inet {
                address 10.0.3.4/32;
            }
            family iso {
                address 49.0003.0100.0000.3004.00;
            }
        }
    }
}
routing-options {
    aggregate {
        route 10.0.4.0/22;
    }
}
protocols {
    isis {
        interface all;
        interface em1.0 {
            level 1 disable;
        }
        interface em2.0 {
            level 1 disable;
        }
        interface em4.0 {
            level 2 disable;
        }
        interface lo0.0 {
            level 1 disable;
        }
    }
}

[edit]
root@PE4#

Result:

[edit]
root@PE5# run show route 10.0.5.0/24

inet.0: 23 destinations, 27 routes (23 active, 0 holddown, 0 hidden)
+ = Active Route, - = Last Active, * = Both

10.0.5.0/24        *[IS-IS/18] 00:14:36, metric 73
                    > to 10.0.2.10 via em1.0

According to configuration on L1/L2 router, PE5 must dont have above result.

[jtb]

hi,

could you elaborate your claim 'PE5 must dont have above result' ? We have PE4 config, 'show route' from the PE5 and must guess what's wrong with it. Unfortunately the crystal ball is powered-off at this moment :-)

Any info about IS-IS adjacencies ? Relevant LSDB contents ?  'show route 10.0.5.0/24' show PE4 ?

jtb

[Saurabh]

could u pls elaborate ur point here?

[Toufiq-ur-Rehman]

I am sorry, I made the question mor complex.please find below more clarification.

I have five routers i.e. PE1, PE2, PE3, PE4, and PE5

Level-1 routers = PE1 and PE2

L1/L2 routers = PE3, PE4 and PE5

10.0.5.0/24 network is directly connected with PE1 and PE2 routers and I have never made any policy to redistributed it in ISIS.I have pasted only one routers coonfiguration here i.e. PE4 and PE3 has similar configuration.

Question:why I can see 10.0.5.0/24 subnet on PE5 i.e. directly connected with PE3 and PE4.

[Saurabh]

As per your explanation it is yet not cleared that where exactly the 10.0.5.0/24 is directly connected between PE1-PE2 or PE3-PE4.

Irrespective of that this is normal behavior of ISIS.

If you configure family iso for an interface ,directly connected subnet to that interface will be advertised in to the ISIS no policy required.

same is with ospf .

accept the solution if this answers your query or let me know for further help.

[jtb]

hi,

it would be great to see more details (show isis database, show isis adjacency) but let's start guessing:

- 10.0.5.0/24 connected to L1 routers: PE1, PE2 

- PE1,PE2 advertise the route in L1 IS-IS hierarchy

- 'show route 10.0.5.0/24' from PE5 shows the prefix is reachable via next-hop 10.0.2.10 (PE4 address); it's L2 IS-IS route

What does it mean ? PE4 is L1-L2 IS-IS router and it leaked the prefix from L1 to L2. It is how IS-IS works: all L1 routes are leaked to L2 (~OSPF backbone area).

Just look at the PE4:

- show route 10.0.5.0/24 -  should be listed as a IS-IS L1 route

- show isis database detail -  the prefix will be present in PE1 and PE2 L1 LSPs  and PE4 L2 LSP

If it's still not clear, please explain what you would expect to see regarding the route on PE5 and why, also attach the results of 'show isis database detail' from PE4 and PE5.

jtb

[Toufiq-ur-Rehman]

Thanks to all.
10.0.5.0/24 subnet was configured on PE1&PE2 routers but I have never added in ISIS or never created any policy to redistrute any directly connected network in ISIS domain so it should be available on PE5 router.

Any how my issue was resolved by just restarting the routers.

[niko_sianipar]

Hi saurabh. from your statement: If you configure family iso for an interface ,directly connected subnet to that interface will be advertised in to the ISIS no policy required. same is with ospf . What do you mean with "same with ospf"?

[JNPRdhanks]

Please see this post and reply back.

http://forums.juniper.net/t5/Routing/Please-include-configurations-and-topologies-when-you-re-having...