After a little more investigation, I think the problem is that our P2 router is not learning a set of prefixes via LDP that it should be, so it is sending them unlabeled to PE2. We assumed that both P routers had the right labels, but that doesn't appear to be the case.
On Tue, Jul 30, 2013 at 12:20 PM, John Neiberger <[email protected]>wrote: > I guess I should rephrase. We have configured "mpls ip-ttl-propagate > disable" to try to hide the labeled part of the path. For whatever reason, > we always get something like the following: > CE1#trace 10.6.10.1 source lo0 > Type escape sequence to abort. > Tracing the route to 10.6.10.1 > VRF info: (vrf in name/id, vrf out name/id) > 1 192.168.105.50 0 msec 0 msec 0 msec > 2 192.168.62.2 [MPLS: Label 16018 Exp 0] 4 msec 0 msec 0 msec > 3 192.168.62.60 0 msec 0 msec 0 msec > 4 192.168.106.61 4 msec * 0 msec > CE1# > If I trace from CE1 to the loopback of PE2, which is the same path, it > works as expected and the labeled part of the path is hidden: > > CE5#trace 10.6.1.1 source lo0 > Type escape sequence to abort. > Tracing the route to 10.6.1.1 > VRF info: (vrf in name/id, vrf out name/id) > 1 192.168.105.50 4 msec 0 msec 0 msec > 2 192.168.62.60 0 msec * 0 msec > > > On Tue, Jul 30, 2013 at 11:43 AM, Jared Mauch <[email protected]>wrote: > >> Disable TTL != don't copy label into ICMP TTL Expired message. >> >> - Jared >> >> On Jul 30, 2013, at 1:37 PM, John Neiberger <[email protected]> wrote: >> >> > I think either we're just doing something wrong or perhaps we're running >> > into a bug. I did find this one, which sounds similar: >> > >> > https://tools.cisco.com/bugsearch/bug/CSCtd17126 >> > >> > I'm not sure if that is fixed in 4.1.0 or not. >> > >> > >> > On Tue, Jul 30, 2013 at 11:01 AM, John Neiberger <[email protected] >> >wrote: >> > >> >> W >> >> e're running into an interesting problem. We have a simple lab setup >> like >> >> this: >> >> >> >> CE1 -- PE1 --- P1 --- P2 --- PE2 --- CE2 >> >> >> >> We have "mpls ip-ttl-propagate disable" on all PE and P routers, but >> if we >> >> trace from CE1 to CE2, we still see an MPLS label coming from the PE2 >> >> router. If we trace CE2 to CE1, we see a label on the hop from P1 to >> PE1. >> >> >> >> If we have ttl propagation completely disabled, why would we still see >> the >> >> label and P-to-PE link in the path? >> >> >> >> All P and PE routers are IOS XR running 4.1.0. >> >> >> >> Thanks, >> >> John >> >> >> > _______________________________________________ >> > cisco-nsp mailing list [email protected] >> > https://puck.nether.net/mailman/listinfo/cisco-nsp >> > archive at http://puck.nether.net/pipermail/cisco-nsp/ >> >> > _______________________________________________ cisco-nsp mailing list [email protected] https://puck.nether.net/mailman/listinfo/cisco-nsp archive at http://puck.nether.net/pipermail/cisco-nsp/
