[c-nsp] 2 x "new" ME3600's, 1 fails to reach one PE only in VRF's

[Adam Vitkovsky]

On the ME you can debug why the label is being dropped/not accepted for the "problem"PE's loopback.
Or what label, if any, is allocated for the "problem"PE's loopback by the penultimate hop router.

adam

From: CiscoNSP List [mailto:cisconsp_list at hotmail.com]
Sent: 20 April 2015 22:49
To: Adam Vitkovsky; cisco-nsp at puck.nether.net
Subject: RE: [c-nsp] 2 x "new" ME3600's, 1 fails to reach one PE only in VRF's

One thing I do notice, is that the "problem" PE doesnt have a label(After nexthop) when issuing "#sh ip cef xxx detail"...all other PE's do?


eg. a "working" PE, from this ME3600:


sh ip cef xxx.xxx.xxx.217/32 detail

xxx.xxx.xxx.217/32, epoch 0

  local label info: global/20661

  2 RR sources [heavily shared]

  nexthop xxx.xxx.xxx.232 GigabitEthernet0/3 label 333


vs


 #sh ip cef xxx.xxx.xxx.222/32 detail
 xxx.xxx.xxx.222/32, epoch 0
 local label info: global/20625
 nexthop xxx.xxx.xxx.232 GigabitEthernet0/3



> From: cisconsp_list at hotmail.com<mailto:cisconsp_list at hotmail.com>
> To: adam.vitkovsky at gamma.co.uk<mailto:adam.vitkovsky at gamma.co.uk>; cisco-nsp at puck.nether.net<mailto:cisco-nsp at puck.nether.net>
> Date: Tue, 21 Apr 2015 08:11:52 +1030
> Subject: Re: [c-nsp] 2 x "new" ME3600's, 1 fails to reach one PE only in VRF's
>
> Thanks Adam - shutdown int vlan36, but unfortunately the issue still persists...I also did a "clear ip route *"
>
> #sh ip cef xxx.xxx.xxx.222/32 detail
> xxx.xxx.xxx.222/32, epoch 0
> local label info: global/20625
> nexthop xxx.xxx.xxx.232 GigabitEthernet0/3
>
>
> #ping vrf CUSTA 10.2.4.1
> Type escape sequence to abort.
> Sending 5, 100-byte ICMP Echos to 10.2.4.1, timeout is 2 seconds:
> .....
> Success rate is 0 percent (0/5)
>
> If it was due to this bug, wouldnt it impact on "all/most?" traffic...i.e. the box can get to all our other PE's in VRF+Global....it's only VRF traffic to this one PE that appears to fail...Global(as mentioned) to this PE works fine?
>
> Cheers.
> From: Adam.Vitkovsky at gamma.co.uk<mailto:Adam.Vitkovsky at gamma.co.uk>
> To: cisconsp_list at hotmail.com<mailto:cisconsp_list at hotmail.com>; cisco-nsp at puck.nether.net<mailto:cisco-nsp at puck.nether.net>
> Subject: RE: [c-nsp] 2 x "new" ME3600's, 1 fails to reach one PE only in VRF's
> Date: Mon, 20 Apr 2015 11:53:16 +0000
>
> I'm sorry about that I did not follow up on this problem.
>
>
>
> IP LFA is not supported on VLAN interfaces (at least not on 15.3(3)S4)
>
> Bug:
>
> Whenever IP LFA is used and a backup path is computed via VLAN interface HW forwarding gets corrupted on the box.
>
> You are "lucky" though, as when we ran into this the box stopped forwarding all transit traffic (only traffic to the box was not affected fortunately)
>
>
>
> The workaround is to never use VLAN interfaces with IP FRR.
>
>
>
> So would you please try shutting down the VLAN36 interface if it helps (provided there are no other VLAN interfaces that can be used as LFA backup link)?
>
>
>
>
>
> > ME02:
>
> > #sh ip cef xxx.xxx.xxx.222/32 detail
>
> > xxx.xxx.xxx.222/32, epoch 0
>
> > local label info: global/20625
>
> > 2 RR sources [heavily shared]
>
> > nexthop xxx.xxx.xxx.232 GigabitEthernet0/3 label [none|674]
>
> > repair: attached-nexthop xxx.xxx.xxx.234 Vlan36 <==========
>
> > nexthop xxx.xxx.xxx.234 Vlan36, repair <=======
>
> >
>
>
>
> adam
>
>
>
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