Two should work just fine. Does for me anyway. First, I pasted in the configs from Cat1, R1 and R2 as is. Then waited for spanning tree. ;) R2(config-if)#do ping 200.0.0.1 Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 200.0.0.1, timeout is 2 seconds: ..... Success rate is 0 percent (0/5) R2(config-if)# *Jun 11 04:01:20.395: %BGP-5-ADJCHANGE: neighbor 200.0.0.1 Up R2(config-if)#do ping 200.0.0.1 Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 200.0.0.1, timeout is 2 seconds: !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 4/5/8 ms R2(config-if)#do sh run | s bgp router bgp 65256 no synchronization bgp log-neighbor-changes bgp confederation identifier 200 bgp confederation peers 65078 neighbor 150.50.24.4 remote-as 300 neighbor 150.50.24.4 filter-list 1 out neighbor 150.50.100.5 remote-as 65256 neighbor 150.50.100.5 next-hop-self neighbor 150.50.100.5 route-map 200Filter out neighbor 200.0.0.1 remote-as 100 neighbor 200.0.0.1 ebgp-multihop 3 no auto-summary
<<<Notice here that the multihop is 3 as the solutions have, and see above where the peer came up>>> R2(config-if)#router bgp 65256 R2(config-router)#no neigh 200.0.0.1 R2(config-router)# *Jun 11 04:02:01.099: %BGP-5-ADJCHANGE: neighbor 200.0.0.1 Down Neighbor deleted R2(config-router)#do sh run | s bgp router bgp 65256 no synchronization bgp log-neighbor-changes bgp confederation identifier 200 bgp confederation peers 65078 neighbor 150.50.24.4 remote-as 300 neighbor 150.50.24.4 filter-list 1 out neighbor 150.50.100.5 remote-as 65256 neighbor 150.50.100.5 next-hop-self neighbor 150.50.100.5 route-map 200Filter out no auto-summary R2(config-router)#neigh 200.0.0.1 remote-as 100 R2(config-router)#do sh run | s bgp router bgp 65256 no synchronization bgp log-neighbor-changes bgp confederation identifier 200 bgp confederation peers 65078 neighbor 150.50.24.4 remote-as 300 neighbor 150.50.24.4 filter-list 1 out neighbor 150.50.100.5 remote-as 65256 neighbor 150.50.100.5 next-hop-self neighbor 150.50.100.5 route-map 200Filter out neighbor 200.0.0.1 remote-as 100 no auto-summary R2(config-router)#neigh 200.0.0.1 ebgp-multihop 2 <<<Note the removal of the peer, and the appropriate deletion. Then it's recreated with multihop 2>>> R2(config-router)#do sh ip bgp sum BGP router identifier 200.0.0.2, local AS number 65256 BGP table version is 5, main routing table version 5 Neighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/PfxRcd 150.50.24.4 4 300 0 0 0 0 0 never Active 150.50.100.5 4 65256 0 0 0 0 0 never Active 200.0.0.1 4 100 0 0 0 0 0 never Active <<<Ready and waiting>>> R2(config-router)#do deb ip pack det IP packet debugging is on (detailed) R2(config-router)# *Jun 11 04:03:01.007: IP: tableid=0, s=150.50.17.2 (local), d=200.0.0.1 (FastEthernet1/0), routed via FIB *Jun 11 04:03:01.007: IP: s=150.50.17.2 (local), d=200.0.0.1 (FastEthernet1/0), len 44, sending *Jun 11 04:03:01.011: TCP src=34362, dst=179, seq=1444273798, ack=0, win=16384 SYN *Jun 11 04:03:01.015: IP: tableid=0, s=200.0.0.1 (FastEthernet1/0), d=150.50.17.2 (FastEthernet1/0), routed via RIB *Jun 11 04:03:01.015: IP: s=200.0.0.1 (FastEthernet1/0), d=150.50.17.2 (FastEthernet1/0), len 44, rcvd 3 *Jun 11 04:03:01.015: TCP src=179, dst=34362, seq=2326681210, ack=1444273799, win=16384 ACK SYN *Jun 11 04:03:01.015: IP: tableid=0, s=150.50.17.2 (local), d=200.0.0.1 (FastEthernet1/0), routed via FIB *Jun 11 04:03:01.015: IP: s=150.50.17.2 (local), d=200.0.0.1 (FastEthernet1/0), len 40, sending *Jun 11 04:03:01.015: TCP src=34362, dst=179, seq=1444273799, ack=2326681211, win=16384 ACK *Jun 11 04:03:01.023: IP: tableid=0, s=150.50.17.2 (local), d=200.0.0.1 (FastEth R2(config-routeernet1/0), routed via FIB *Jun 11 04:03:01.023: IP: s=150.50.17.2 (local), d=200.0.0.1 (FastEthernet1/0), len 85, sending *Jun 11 04:03:01.023: TCP src=34362, dst=179, seq=1444273799, ack=2326681211, win=16384 ACK PSH *Jun 11 04:03:01.043: IP: s=200.0.0.1 (FastEthernet1/0), d=150.50.17.2, len 104, rcvd 0 *Jun 11 04:03:01.047: TCP src=179, dst=34362, seq=2326681211, ack=1444273844, win=16339 ACK PSH *Jun 11 04:03:01.051: %BGP-5-ADJCHANGE: neighbor 200.0.0.1 Up *Jun 11 04:03:01.051: IP: tableid=0, s=150.50.17.2 (local), d=200.0.0.1 (FastEthernet1/0), routed via FIB *Jun 11 04:03:01.051: IP: s=150.50.17.2 (local), d=200.0.0.1 (FastEthernet1/0), len 59, sending *Jun 11 04:03:01.051: TCP src=34362, dst=179, seq=1444273844, ack=2326681275, win=16320 ACK PSH *Jun 11 04:03:01.059: IP: s=200.0.0.1 (FastEthernet1/0), d=150.50.17.2, len 108, rcvd 0 *Jun 11 04:03:01.059: TCP src=179, dst=34362, seq=2326681275, ack=1444273863, win=16320 ACK PSH *Jun 11 04:03:01.059: IP: tableid=0, s=150.50.17.2 (local), d=200.0.0.1 (FastEthernet1/0), routed via FIB *Jun 11 04:03:01.059: IP: s=150.50.17.2 (local), d=200.0.0.1 (FastEthernet1/0), len 78, sending *Jun 11 04:03:01.059: TCP src=34362, dst=179, seq=1444273863, ack=2326681343, win=16252 ACK PSH *Jun 11 04:03:01.071: IP: s=200.0.0.1 (FastEthernet1/0), d=150.50.17.2, len 78, rcvd 0 *Jun 11 04:03:01.071: TCP src=179, dst=34362, seq=2326681343, ack=1444273901, win=16282 ACK PSH *Jun 11 04:03:01.275: IP: tableid=0, s=150.50.17.2 (local), d=200.0.0.1 (FastEthernet1/0), routed via FIB *Jun 11 04:03:01.275: IP: s=150.50.17.2 (local), d=200.0.0.1 (FastEthernet1/0), len 40, sending *Jun 11 04:03:01.275: TCP src=34362, dst=179, seq=1444273901, ack=2326681381, win=16214 ACKr)# R2(config-router)#do sh ip bgp sum BGP router identifier 200.0.0.2, local AS number 65256 BGP table version is 7, main routing table version 7 2 network entries using 234 bytes of memory 2 path entries using 104 bytes of memory 2/1 BGP path/bestpath attribute entries using 248 bytes of memory 1 BGP AS-PATH entries using 24 bytes of memory 0 BGP route-map cache entries using 0 bytes of memory 0 BGP filter-list cache entries using 0 bytes of memory BGP using 610 total bytes of memory BGP activity 4/2 prefixes, 4/2 paths, scan interval 60 secs Neighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/PfxRcd 150.50.24.4 4 300 0 0 0 0 0 never Active 150.50.100.5 4 65256 0 0 0 0 0 never Active 200.0.0.1 4 100 5 4 7 0 0 00:00:10 2 R2(config-router)#do un all All possible debugging has been turned off R2(config-router)# So we see the packets coming in sourced from 150.50.17.2 destined for the loopback interface. Multihop config is 2 and it works! If we were going to/from the loopback on R1, then that would add another hop. But from one loopback to the other loopback may require that you have another hop in there. :) HTH, Scott _____ From: Carlos Valero [mailto:[EMAIL PROTECTED] Sent: Tuesday, June 10, 2008 11:02 PM To: 'OSL CCIE Routing and Switching Lab Exam'; [EMAIL PROTECTED] Subject: Re: [OSL | CCIE_RS] EBGP Multihop Hi, I had forgotten to ask you a question about ebgp-multihop. Since this issue was raised, this question came back to my mind. This is about BGP Lab 7 (v9.0). I know you don't have v9.0 anymore, but this should not be too complicated for you. One of the initial tasks was to configure R1 on AS 100 and R2 on AS 200, but peering with R1's loopback. Of course we need to use ebgp-multihop in this case. But while I was expecting to see "ebgp-multihop 2", the actual solution used "ebgp-multihop 3" I tried "ebgp-multihop 2" just to see, but of course it did not work! But I'm not sure why. If they were peering using a Serial Link, then "ebgp-multihop 2" would be OK; I know that. But in this case R1 and R2 are connected through Switch 1 on VLAN 12. Does the Switch count as an additional hop? If that's the case, is it because the Switch is acting as Layer 3 device? What if the switch was a pure Layer 2 device, with no VLAN? Would I still need "ebgp-multihop 3" instead of "ebgp-multihop 2" ? --- On Tue, 6/10/08, Scott Morris <[EMAIL PROTECTED]> wrote: From: Scott Morris <[EMAIL PROTECTED]> Subject: Re: [OSL | CCIE_RS] EBGP Multihop To: "'OSL CCIE Routing and Switching Lab Exam'" <[email protected]> Date: Tuesday, June 10, 2008, 3:32 PM It's mandatory to have reachability. :) However you choose to do that in order to build your session is between you and your lab requirements! But no reachability = no bgp session! HTH, Scott _____ From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Hari Sent: Tuesday, June 10, 2008 3:01 PM To: [email protected] Subject: [OSL | CCIE_RS] EBGP Multihop Hi all, While configuring EBGP Multihop command in BGP , do we need to configure IGP route or static route for that particular neighbor? Is it mandatory to configure IGP route or static route ? Thanks Hari _____ Bring your gang together. Do your thing. Find your favourite Yahoo! <http://in.rd.yahoo.com/tagline_groups_9/*http://in.promos.yahoo.com/groups/ > Group.
