[j-nsp] MX80 MPLS L3VPN Fragment drops

[Leigh Porter]

> * Leigh Porter <leigh.porter at ukbroadband.com> [2012-11-06 00:46]:
> > A packet dump reveals that the TCP sender (FTP server) will send a
> > segment, the LTE core will encap this segment and fragment the tunnel
> > packet, these fragments enter into an MX80 and into a L3VPN instance
> > but then only the first half of the fragmented datagram ever exits
> the
> > MX80 as an MPLS packet.
> 
> Hi Leigh,
> 
> you might be hitting PR736749:

In L3VPN scenario, transit packets which require fragmentation, traversing over the
mpls core, might get dropped at the egress PE, if the egress PE?s, CE facing interface
is on trio chipset cards. [PR736749: This issue has been resolved.]

It looks like that, but the packet was already fragmented and it was on ingress of a PE ;-)
 
> "Fragmented packets or small packets with padding might get dropped on
> Trio based platforms"
> 
> Which JunOS Version are you using?

10.4R1.5

I have now captured the naughty datagram and when I replay that into the MX80, it gets dropped. So at least I have a fully re-creatable issue now.

--
Leigh

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