[j-nsp] Strange IS-IS Problem

[Eric Van Tol]

Hi all,
I've got a strange ISIS problem and I'm hoping another set of eyes can help me identify what is wrong here.  I've got an MX960 logically connected to a J2320 through two EX2500 switches:

MX960 <==> EX2500 <==> EX2500 <==> J2320

I'm simply trying to get ISIS working between the two routers and it's not coming up.  Traceoptions don't show anything out of the ordinary.

MX960:
xe-1/2/0 {
    vlan-tagging;
    mtu 9192;
    unit 1 {
        vlan-id 1;
        family inet {
            mtu 1500;
            address x.x.x.99/28;
        }
        family iso;
    }
}
lo0 {
    unit 0 {
        family inet {
            address 127.0.0.1/32;
            address x.x.x.74/32;
        }
        family iso {
            address 47.0001.xxxx.xxxx.xxxx.00;
        }
    }
}
...
protocols {
    isis {
        interface xe-1/2/0.1;
        interface lo0.0 {
            passive;
        }
    }
}


J2320:
ge-0/0/0 {
    vlan-tagging;
    mtu 9192;
    unit 1 {
        vlan-id 1;
        family inet {
            mtu 1500;
            address x.x.x.100/28;
        }
        family iso;
    }
}
lo0 {
    unit 0 {
        family inet {
            address 127.0.0.1/32;
            address x.x.x.75/32;
        }
        family iso {
            address 47.0001.xxxx.xxxx.xxxx.00;
        }
    }
}
...
protocols {
    isis {
        interface ge-0/0/0.1;
        interface lo0.0 {
            passive;
        }
    }
}

I can ping fine between the two:

root at router1# run ping x.x.x.99 source x.x.x.100    
PING x.x.x.99 (x.x.x.99): 56 data bytes
64 bytes from x.x.x.99: icmp_seq=0 ttl=64 time=4.890 ms
64 bytes from x.x.x.99: icmp_seq=1 ttl=64 time=2.098 ms
64 bytes from x.x.x.99: icmp_seq=2 ttl=64 time=2.095 ms
64 bytes from x.x.x.99: icmp_seq=3 ttl=64 time=2.130 ms
64 bytes from x.x.x.99: icmp_seq=4 ttl=64 time=4.217 ms
^C
--- x.x.x.99 ping statistics ---
5 packets transmitted, 5 packets received, 0% packet loss
round-trip min/avg/max/stddev = 2.095/3.086/4.890/1.217 ms

If I monitor traffic on either of the interfaces, I see ISIS packets leaving, but nothing coming in.  The EX2500s have a very vanilla config and I'm doing no filtering on them.

Any ideas?

Thanks,
evt