[j-nsp] Krt queue issues

[Darren O'Connor]

Hi all.

I'm looking at replacing my ageing m7i's with MX80s. I have run into a few issues where the RIB is not moved to the FIB in a timely fashion and the router effectively black holes traffic for up to 20 minutes while it empties the krt queue.

My hope that with a beefier MX80, this problem would be gone. However I've been reading reports that this is not the case. 

Here is 1 such example on an MX480: http://www.gossamer-threads.com/lists/nsp/juniper/35385
This is another: http://www.gossamer-threads.com/lists/nsp/juniper/20588

After extensive talking with JTAC I got this response:
"I had read the 20588 thread
previously. It is expected behavior for:

1. routes to be in KRT queue

2. and to be blackholed as they are in there, since PFE is not programmed with
them.



It's not a bug, it's a design limitation. There's a unix socket between the RE
and PFE which has limited bandwidth to process what's called
"ifstate" by developers. There are features upcoming which will help
decrease the blackholing window, like RLI 17564."


So to me this means this problem is a software issue, not hardware. And it's not yet fixed. Hence spending the money on a new box would be of no use.

This particular router for me will be connected to a peering point so will have around 200 neighbours, as well as a transit link with a full BGP table.

Can anyone shed any light on this problem? 

Thanks

Darren