[j-nsp] what happens in JUNOS when interface is disabled/enabled

Martin T m4rtntns at gmail.com
Sun Oct 2 17:30:51 EDT 2011


I have a subinterface which has /29 globally routable IP network
associated with it. Today after recovery of a major routing
instability in the network, this particular /29 network still behaved
tricky- hosts behind this subinterface were able to reach some
Internet hosts, but there was no consistency. If I tried to reach
hosts inside this mentioned /29 network, I always ended up in the
router where this /29 is configured, but got no replies from hosts
inside the /29. This didn't matter if I tried from the same AS where
the /29 belongs to or from some other. Routing table(inet.0 as those
are IPv4 addresses) table entries were correct. Finally I disabled
this particular subinterface, waited few minutes and enabled the
interface which solved the problem- all the hosts in the /29 became
reachable from Internet. However, I didn't detect any differences in
routing table. What might cause such situation? And what happens
internally when interface is disabled/enabled when we talk about
routing?

One thing I remember I didn't check was the content of the forwarding
table. I have no idea how plausible this is, but maybe there was some
inconsistency between the routing table and forwarding table?

However, anyone experienced something similar?


regards,
martin


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