[j-nsp] MTU issue between juniper routers

[Pekka Savola]

On Fri, 25 Mar 2011, meryem Z wrote:
> - MTU on Ge interface is configured to 4484 on both ends of the links. but ping (from P to PE ) greater than 1600 bytes fails.
> - I checked interfaces configuration , and also did a "show interfaces" to verify the effective mtu value used. everything is ok.
> - i'm suspecting some node on the transmission path between the P and the PE configured with the default value of 1500 for GE , but i couldn't find any equivalent command to the linux tracepath on juniper routers.

This is not very probable but:

Check that the packets are not being sent as fragments and dropped 
in receiver's loopback filters.

Even though MTU is high, we've come across unnecessary (IPv6) 
fragmentation when certain conditions are met - PR/571596

-- 
Pekka Savola                 "You each name yourselves king, yet the
Netcore Oy                    kingdom bleeds."
Systems. Networks. Security. -- George R.R. Martin: A Clash of Kings