[j-nsp] MX80 MPLS L3VPN Fragment drops

[Leigh Porter]

Here is the port config:

leigh at agg1.pgt> show configuration interfaces ge-1/1/4
description "UGW9811 2/1/1 for MTU testing";
unit 0 {
    family inet {
        mtu 1500;
        address 10.2.0.241/28;
    }
}

leigh at agg1.pgt>



leigh at agg1.pgt> show configuration routing-instances s1u
instance-type vrf;
interface ge-1/0/2.1100;
interface ge-1/1/4.0;
interface ae0.510;
interface lo0.300;
route-distinguisher 29009:103;
vrf-import s1u-import;
vrf-export s1u-export;
vrf-target target:29009:103;
vrf-table-label;
protocols {
    ospf {
        export VPN-OSPF-export;
        area 0.0.0.0 {
            interface ae0.510;
            interface ge-1/0/2.1100 {
                passive;
            }
            interface ge-1/1/4.0 {
                metric 1;
            }
        }
    }
}

leigh at agg1.pgt>


________________________________________
From: Tima Maryin [timamaryin at mail.ru]
Sent: 06 November 2012 18:54
To: Leigh Porter
Cc: juniper-nsp at puck.nether.net
Subject: Re: [j-nsp] MX80 MPLS L3VPN Fragment drops

On 06.11.2012 18:57, Leigh Porter wrote:
>> * 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 ;-)



That description is not very precise. It affects also transiting
fragments. I'm sure you're hitting this bug.



>> Which JunOS Version are you using?
>
> 10.4R1.5


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