Even I use send-label that's not necessary I don't think I'll lose points doing over-config. What do you guys say?
Bill 2009/10/31 André Luiz Bernardes <[email protected]>: > Got it > > I would change that message to : ALWAYS USE SEND-LABEL on IBGP, DO NOT LOOSE > POINTS! :) > > Thanks > > 2009/10/31 Rick Mur <[email protected]> >> >> That message is quite dangerous to assume. >> Like you saw when the EBGP prefix (where labels are exchanged on the >> ASBR's) is NOT known in your IGP topology. LDP only assigns labels to IGP >> prefixes. Therefore the labels that are exchanged on the AS border, are NOT >> known within that network, like Bryan said, on the RR's. >> You definitely NEED to add send-label on your IBGP neighbors as well so >> the traffic is label switched within your AS as well. It will definitely >> won't work if you have a couple routers within your AS (when they are NOT >> ASBR's). So it's not always when you have 2 connections, it depends on the >> situation, check your LFIB and see how the traffic is label switched (or >> not) >> -- >> >> Regards, >> >> Rick Mur >> CCIE2 #21946 (R&S / Service Provider) >> Sr. Support Engineer – IPexpert, Inc. >> URL: http://www.IPexpert.com >> On 30 okt 2009, at 20:34, André Luiz Bernardes wrote: >> >> Hey Brian and Shai >> >> I believe some things are for the better !!! Since this morning I >> believed that sending labels other than to EBGP was just cosmetic as all the >> labs I'd done worked fine without that. What I didn't took in account was >> what happened when we have dual IPV4 eBGP between the ASs and for some >> reason traffic is asymmetrical or just preferring the IBGP path to reach the >> next-hop. >> >> I am working on INE workbook right now and could reproduce this issue. >> What happened was that the VPN PE router was also the ASBR and instead of >> preferring the ASBR interface to get to the next AS, it was doing so via >> IBGP than taking the second ASBR. >> >> Sorry to post outputs from another vendor workbook but I can wait to share >> that :) >> >> >> I am sitting on the PE router on AS 100, which is also de ASBR. The PE >> router on AS 200 is 20.1.1.1 >> >> Rack1R7#ping 119.0.0.1 sou lo0 >> Sending 5, 100-byte ICMP Echos to 119.0.0.1, timeout is 2 seconds: >> Packet sent with a source address of 10.1.7.7 >> ..... >> Success rate is 0 percent (0/5) >> >> >> Rack1R6#sh ip cef 20.1.1.1 detail >> 20.1.1.1/32, version 185, epoch 0, cached adjacency 20.1.46.4 >> 0 packets, 0 bytes >> tag information set, shared >> local tag: BGP route head >> via 20.1.4.4, 4 dependencies, recursive >> next hop 20.1.46.4, Ethernet0/0 via 20.1.4.4/32 >> valid cached adjacency >> tag rewrite with Et0/0, 20.1.46.4, tags imposed: {} <<<<< NO >> LABEL HUMMMMMMMM >> >> >> >> Rack1R6#sh ip bgp labels >> Network Next Hop In Label/Out Label >> 20.1.1.1/32 20.1.4.4 nolabel/nolabel <<<<< No label from >> iBGP path >> 20.1.1.1/32 20.1.26.2 nolabel/20 <<<<< There is a >> label here learned via eBGP >> >> >> >> **** I CONFIGURED SEND-LABEL BETWEEN MY IBGP NEIGHBORS WITHIN AS 100 >> ***** >> >> >> Rack1R6#sh ip cef 20.1.1.1 detail >> 20.1.1.1/32, version 193, epoch 0, cached adjacency 20.1.46.4 >> 0 packets, 0 bytes >> tag information set >> local tag: 29 >> fast tag rewrite with Et0/0, 20.1.46.4, tags imposed: {31} >> via 20.1.4.4, 4 dependencies, recursive >> next hop 20.1.46.4, Ethernet0/0 via 20.1.4.4/32 >> valid cached adjacency >> tag rewrite with Et0/0, 20.1.46.4, tags imposed: {31} <<<<< HERE IS >> MY LABEL GUYS!!!!!!!!!! >> >> >> Rack1R6#sh ip bgp labels >> Network Next Hop In Label/Out Label >> 20.1.1.1/32 20.1.4.4 29/31 <<<<< Label from >> IBGP >> 20.1.1.1/32 20.1.26.2 29/20 <<<<< Label from >> EBGP >> >> >> NOW MY TRAFFIC GETS THRU!!!!!!!!!!!!!!!!!!!! >> >> Rack1R7#ping 119.0.0.1 sou lo0 >> >> Type escape sequence to abort. >> Sending 5, 100-byte ICMP Echos to 119.0.0.1, timeout is 2 seconds: >> Packet sent with a source address of 10.1.7.7 >> !!!!! >> Success rate is 100 percent (5/5), round-trip min/avg/max = 92/94/100 ms >> >> >> >> Message is... USE SEND-LABELS between IBGP when doing Inter-AS VPNs with >> dual interconnections!!! >> >> Best >> >> Andre >> >> >> >> On Fri, Oct 30, 2009 at 3:26 PM, Bryan Bartik <[email protected]> >> wrote: >>> >>> Hey guys, >>> >>> I think it depends on what the scenario is, and what the next-hop is of >>> the VPN route. For example, if you are doing MP-EBGP between >>> route-reflectors in inter-AS scenario, the PE routers may need labels for >>> the PE routers in the other AS. If you do not have send-label between the >>> RRs and the PEs (IBGP) then the PE routers cannot properly tag the packets. >>> >>> On Fri, Oct 30, 2009 at 9:36 AM, Shai Loufton <[email protected]> wrote: >>>> >>>> I am now actually on a proctor labs' 7200/ATM Rack now doing the second >>>> VOL II lab and I see exactly what you describe – it works with just >>>> enabling >>>> "send-label" on the ASBRs (and "set mpls-label" if there is a route-map in >>>> between). >>>> >>>> >>>> >>>> I cannot think of a reason of doing the LSP as a BGP LSP from end to end >>>> – can anyone else comment here about this also? >>>> >>>> >>>> >>>> BTW – thanks André Luiz Bernardes for helping me before …. – I will do >>>> the 1st lab tomorrow again – hopefully will understand it all and all will >>>> work eventually after I am done with it …. >>>> >>>> >>>> >>>> >>>> Shai L >>>> >>>> >>>> >>>> From: [email protected] >>>> [mailto:[email protected]] On Behalf Of Andr? Luiz >>>> Bernardes >>>> Sent: Friday, October 30, 2009 4:17 PM >>>> To: [email protected] >>>> Subject: [OSL | CCIE_SP] BGP Labels, send or not to send.... >>>> >>>> >>>> >>>> Hello guys >>>> >>>> I have this doubt here.. when configuring Inter-AS VPN we have to build >>>> an e2e label path to get VPN traffic flow between ISPs. Most of the times >>>> we >>>> are required to exchange loopbacks labels via IPv4 eBGP sessions between >>>> ASs >>>> since LDP is not allowed. >>>> >>>> Well... I have done this several times already on different vendor's >>>> wookbooks and that works fine just by configuring BGP send-label feature >>>> (and mpls set-label on route-maps) only on EBGP sessions. My questions is >>>> why worbook solutions always require configuring BGP label distribuition >>>> also for IBGP session? Is this just a best practice or is there any >>>> underlying issue that does not come up on workbook scenarios due to reduced >>>> topology... >>>> >>>> Thanks >>>> >>>> Andr'e >>>> >>>> _______________________________________________ >>>> For more information regarding industry leading CCIE Lab training, >>>> please visit www.ipexpert.com >>>> >>> >>> >>> >>> -- >>> 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 >> > > > _______________________________________________ > For more information regarding industry leading CCIE Lab training, please > visit www.ipexpert.com > > _______________________________________________ For more information regarding industry leading CCIE Lab training, please visit www.ipexpert.com
