From: Dalu-Chandu, Jay (JD163604@NCR.COM)
Date: Thu Nov 11 2004 - 06:57:26 GMT-3
Mike,
Thanks for your advice. I have done all the basic checks and confirmed my
configuration. I have also tested this scenario using 3 different routers
successfully.
I have tried clearing the cef table and reloading R5 but the same problem
persists. I have noticed that labels are being propagated and received for
R1's loopback address but not installed in the Lfib. See commands below;
R5#show mpls ldp bindings 192.168.1.1 32
tib entry: 192.168.1.1/32, rev 65
local binding: tag: 508
remote binding: tsr: 192.168.3.3:0, tag: 307
R5#show mpls forwarding-table 192.168.1.1
Local Outgoing Prefix Bytes tag Outgoing Next Hop
tag tag or VC or Tunnel Id switched interface
508 Untagged 192.168.1.1/32 0 Se4/3 point2point
R5#show ip cef 192.168.1.1
192.168.1.1/32, version 47, epoch 0, cached adjacency to Serial4/3
0 packets, 0 bytes
tag information set, shared
local tag: 508
via 172.16.35.6, Serial4/3, 1 dependency
next hop 172.16.35.6, Serial4/3
valid cached adjacency
tag rewrite with Se4/3, point2point, tags imposed: {}
The mpls ping command is available and works both ways.
R5#ping tag 192.168.1.1
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 192.168.1.1, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 16/16/20 ms
R5#
R1#ping tag 192.168.5.5
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 192.168.5.5, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 16/16/20 ms
R1#
Any further thoughts?
Regards
Jay
-----Original Message-----
From: Mike Bernico [mailto:mbernico@illinois.net]
Sent: 10 November 2004 19:45
To: Dalu-Chandu, Jay; comserv@groupstudy.com; ccielab@groupstudy.com
Subject: RE: MPLS/VPN/ISIS
Hard to say without your configs. Here are some things to try that might
help...
Since you're only getting one label in your cef show command, you must be
missing one.
Does your version of IOS support mpls ping? That definitely helps. If it
does, do an extended mpls ping from loopback to loopback and verify you've
got yourself an LSP that works.
It sounds like you've already done the most important part, by making sure
that the exact route exists end-to-end for your loopbacks.
Also you should probably verify the obvious stuff if you haven't. LDP
neighbors, cef on all routers, stuff like that.
Also maybe use "show mpls forwarding-table" to check the lsp by hand if you
can't mpls ping.
Ok, so then if all that works, maybe it is the label BGP sends?
Possibly check to make sure that neighbor x.x.x.x send-community extended is
turned on.
Anyway, that's what I'd try first. Let me know what it is when you find it!
Good Luck,
Mike
-----Original Message-----
From: Dalu-Chandu, Jay [mailto:JD163604@NCR.COM]
Sent: Wednesday, November 10, 2004 11:50 AM
To: comserv@groupstudy.com; ccielab@groupstudy.com
Subject: MPLS/VPN/ISIS
Guys,
I have a question regarding a sample lab configuration I'm currently working
on. The IGP used is ISIS with two areas 49.0001 and 49.0005. Within area 1
I have an L1 only router attached to a L1L2 router, which is in turn
attached to a L2 router in area 5.
R1(L1)--------R3(L1/L2)----------R5(L2)
R1 and R5 are PE routers, R3 is a P router. A BGP relationship for
vpnv4
has been established to the loopbacks of the PE devices. I can see the vrf
routes associated on each PE device. When I try to ping an IP address
within the vrf from R1 to R5 I see cef drops (debug ip cef drops). I notice
that no label exists for the next-hop-address of R5 because I am only
receiving the default from R3. To correct this I route-leaked L2 into
L1
for R5's loopback.
Now I have a label and no more cef packet drops on R1. But I still cannot
ping. R5 complains that it does not have a parent tag when I try pinging
from there (debug ip cef drops). I also notice that only a single label is
imposed when looking at show ip cef vrf xxx A.B.C.D? Can anyone help, am I
missing something obvious?
Regards
Jay Dalu-Chandu
-- Network Consultant (BEng, CCNP) NCR UK Limited Mobile: 07803231944 Email: jay.dalu-chandu@ncr.com
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