Thanks Guys, I am using 7200s in dynamips with 12.2S code. In fact, this is a mock set up of vol 2 lab 4, I just took everything else out of the equation. I started from scratch just doing the MPLS VPN scenarios. Even R2 is not doing anything (ospf or ldp) right now. I am also just using physical interfaces on my frame relay cloud :) I don't see the client tagging the packets but I could look deeper into this. It's just amazing that is every 3 minutes pretty much on the dot! I wonder if it's some type of CSC bug having to do with MPLS on the VRF interface...I will do some more testing and let you know.
On Fri, Sep 4, 2009 at 3:22 AM, Antonie Henning - MWEB <[email protected]>wrote: > Had a similar issue. I narrowed it down to point to point frame-relay > subinterface with csc igp (ospf) and ldp enabled. > > What I saw was a loop. The client would tag packets to the carrier for the > directly connected subnet. I was expecting to see it pop the label: > > R2(config-subif)#do sh ip cef 123.2.6.6 > 123.2.6.0/24 > attached to Serial4/0.206 label 614 > > The 614 label then sends the packet back to the client and a loop forms: > > R2(config)#do trace 123.2.6.6 > > Type escape sequence to abort. > Tracing the route to 123.2.6.6 > > 1 123.2.6.6 [MPLS: Label 614 Exp 0] 8 msec 32 msec 12 msec > 2 123.2.6.2 20 msec 40 msec 40 msec > 3 123.2.6.6 [MPLS: Label 614 Exp 0] 44 msec 24 msec 44 msec > 4 123.2.6.2 20 msec 48 msec 64 msec > 5 123.2.6.6 [MPLS: Label 614 Exp 0] 40 msec 24 msec 40 msec > 6 123.2.6.2 48 msec 72 msec 60 msec > 7 123.2.6.6 [MPLS: Label 614 Exp 0] 60 msec 36 msec 64 msec > 8 123.2.6.2 56 msec 60 msec 88 msec > 9 123.2.6.6 [MPLS: Label 614 Exp 0] 60 msec 108 msec 60 msec > > Changing the frame-relay config to use the main interface solved the > problem. > > Hth > 21500.net > > -----Original Message----- > From: [email protected] [mailto:[email protected]] On Behalf Of > Francisco Baena > Sent: 04 September 2009 08:11 AM > To: 'Bryan Bartik'; [email protected]; [email protected] > Subject: RE: Carrier Supporting Carrier (CSC) - LDP peering between SPs > drops every 3 minutes > > Make it two. I had the same problem with vol II - Lab 4 (I think), but from > R2 to R6. > > At that point I blamed on dynamips being buggy as all the routing/MPLS > tables seem fine. > > I look forward to a resolution on this. The interesting thing is that when > I > shut down the connection from R1 to R2, the problem went away, so it sounds > like an IGP issue. However even making a Sham link between r6 and r9 and > increasing the OSPF cost from R1 to R2 (to ensure AS200 was the exit > point), > made no difference. > > I would say that a possible workaround could be to make the R1-R9 LDP > sessions targeted, but obviously what we all want to know is what the heck > happened there in the first place. > > During my testing I disabled MPLS TE too in AS200, just in case, but no > cigar.... > > Cheers, > Francisco > http://www.linkedin.com/in/fbaena > > > -----Original Message----- > From: [email protected] [mailto:[email protected]] On Behalf Of > Bryan Bartik > Sent: 04 September 2009 05:14 > To: [email protected]; [email protected] > Subject: Carrier Supporting Carrier (CSC) - LDP peering between SPs drops > every 3 minutes > > Hello, > > I am running an inter-as + CSC scenario with OSPF and MPLS between the SPs. > The LDP peering is dropping exactly every 3 minutes and coming back up. > Connectivity is fine throughout the VPN when the session is up. I don't see > any route flapping in the debugs. > > AS65123[R3]---------[R8]AS100---------AS200[R9]---------[R1]AS65123 > > AS100 and AS200 have an inter-as VPN supporting the 2nd level carrier > AS65123. > R9 and R8 have vrf interfaces connected to R1 and R3 respectively. > R1 has an LDP/OSPF peering with R9 (in the vrf) in AS100 > R3 has an LDP/OSPF peering with R8 (in the vrf) in AS200 > > Both LDP sessions are bouncing on queue every 3 minutes! Here is R8 for > example: > > R8# > *Sep 3 21:50:49.575: %LDP-5-NBRCHG: LDP Neighbor 123.123.123.3:0 is DOWN > *Sep 3 21:50:59.475: %LDP-5-NBRCHG: LDP Neighbor 123.123.123.3:0 is UP > *Sep 3 21:53:59.491: %LDP-5-NBRCHG: LDP Neighbor 123.123.123.3:0 is DOWN > *Sep 3 21:54:09.291: %LDP-5-NBRCHG: LDP Neighbor 123.123.123.3:0 is UP > *Sep 3 21:57:09.311: %LDP-5-NBRCHG: LDP Neighbor 123.123.123.3:0 is DOWN > *Sep 3 21:57:19.331: %LDP-5-NBRCHG: LDP Neighbor 123.123.123.3:0 is UP > *Sep 3 22:00:19.351: %LDP-5-NBRCHG: LDP Neighbor 123.123.123.3:0 is DOWN > *Sep 3 22:00:29.239: %LDP-5-NBRCHG: LDP Neighbor 123.123.123.3:0 is UP > > Now just before the session dies I get the following from "debug mpls ldp > transport events interface x/x". This is from R9: > > R9# > *Sep 3 22:09:27.295: ldp: Send ldp hello; Serial1/2, src/dst > 123.1.9.9/224.0.0.2, inst_id 0 > *Sep 3 22:09:28.787: ldp: Rcvd ldp hello; Serial1/2, from 123.1.9.1 ( > 123.123.123.1:0), intf_id 0, opt 0xC > *Sep 3 22:09:32.127: ldp: Send ldp hello; Serial1/2, src/dst > 123.1.9.9/224.0.0.2, inst_id 0 > *Sep 3 22:09:33.239: ldp: Rcvd ldp hello; Serial1/2, from 123.1.9.1 ( > 123.123.123.1:0), intf_id 0, opt 0xC > *Sep 3 22:09:36.111: ldp: Send ldp hello; Serial1/2, src/dst > 123.1.9.9/224.0.0.2, inst_id 0 > *Sep 3 22:09:36.907: tagcon: Session KeepAlive timer expired, peer > 123.123.123.1:0 (pp 0x64027BD8) > *Sep 3 22:09:36.911: ldp: Close LDP transport conn for adj 0x63486648 > *Sep 3 22:09:36.915: ldp: Closing ldp conn 123.1.9.9:646 <-> > 123.123.123.1:11015, adj 0x63486648 > *Sep 3 22:09:36.919: ldp: Adj 0x63486648; state set to closed > *Sep 3 22:09:36.923: %LDP-5-NBRCHG: LDP Neighbor 123.123.123.1:0 is DOWN > > Even though I am sending and receiving hellos, I am getting the session > keepalive timer expired. Any ideas? > > Thanks! > -- > Bryan Bartik > CCIE #23707 (R&S), CCNP > Sr. Support Engineer - IPexpert, Inc. > URL: http://www.IPexpert.com > > _____________________________________________________________________ > Subscription information: http://www.groupstudy.com/list/comserv.html > > No virus found in this incoming message. > Checked by AVG - www.avg.com > Version: 8.5.409 / Virus Database: 270.13.76/2343 - Release Date: 09/03/09 > 05:50:00 > > _____________________________________________________________________ > Subscription information: http://www.groupstudy.com/list/comserv.html > Connect with South Africa’s leading Internet Service Provider and discover > the magic of the Internet and all its possibilities. > Call 08600 32000 or click here(http://www.mweb.co.za/productsservices/) > for more. > > MWEB :-) CONNECT AND YOU CAN. > > This electronic communication and the attached file(s) are subject to a > disclaimer which can be accessed on the following link: > Disclaimer - or copy the following URL into your browser - > http://www.mweb.co.za/disclaimer. > If you are unable to view the disclaimer, please contact [email protected] a > copy. > -- Bryan Bartik CCIE #23707 (R&S), CCNP Sr. Support Engineer - IPexpert, Inc. URL: http://www.IPexpert.com
_______________________________________________ For more information regarding industry leading CCIE Lab training, please visit www.ipexpert.com
