bgp on gns3vault...

if you haven't looked at gns3vault yet, you really should... rene has gone to a lot of effort to offer instructional labs that are challenging and great practice tools at once...

here is the latest one i did... http://gns3vault.com/BGP/ebgp-external-bgp.html

downloading his zips and scaling them to fit in a topology of your choosing is easy enough...  i've said before i like using 7200's so i find/replace his instances of 3640's, and change the idle pc value, the slots/interfaces, directories, then dump his configs into the same new directory, and i'm off... usually only takes a few minutes to whip up one of his labs into my environment; faster than building them from scratch...  i've found very few mistakes along the way... and gns3 will help you troubleshoot conversion mistakes if you pay attention to the console window...

i set up bgp as per jeremy cioara's guidance on his ccie youtube videos... i'm certain this is the preferred method... http://www.youtube.com/watch?v=xIYeBM3vTWo

i went further with rene's lab, you might say over configured... i like to add bgp only reachable loopbacks just to prove to myself that the igp isn't doing all the work...

Wool#sh ip bgp
BGP table version is 9, local router ID is 1.1.1.1
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
              r RIB-failure, S Stale, m multipath, b backup-path, f RT-Filter,
              x best-external, a additional-path, c RIB-compressed,
Origin codes: i - IGP, e - EGP, ? - incomplete
RPKI validation codes: V valid, I invalid, N Not found

     Network          Next Hop            Metric LocPrf Weight Path
 *>  1.1.1.0/24       0.0.0.0                  0         32768 i
 *>  2.2.2.0/24       2.2.2.2                  0             0 2 i
 *>  3.3.3.0/24       2.2.2.2                                0 2 3 i
 *>  4.4.4.0/24       2.2.2.2                                0 2 3 4 i
 *>  11.11.11.0/24    0.0.0.0                  0         32768 i
 *>  22.22.22.0/24    2.2.2.2                  0             0 2 i
 *>  33.33.33.0/24    2.2.2.2                                0 2 3 i
 *>  44.44.44.0/24    2.2.2.2                                0 2 3 4 i

Wool#sh ip route ospf

Gateway of last resort is not set

      2.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
O        2.2.2.2/32 [110/2] via 192.168.12.2, 01:01:15, FastEthernet0/0
      3.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
O        3.3.3.3/32 [110/3] via 192.168.12.2, 00:53:54, FastEthernet0/0
      4.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
O        4.4.4.4/32 [110/4] via 192.168.12.2, 00:53:02, FastEthernet0/0
O     192.168.23.0/24 [110/2] via 192.168.12.2, 00:55:19, FastEthernet0/0
O     192.168.34.0/24 [110/3] via 192.168.12.2, 00:53:54, FastEthernet0/0

Silk#sh run | sec router
router ospf 1
 network 2.2.2.0 0.0.0.255 area 0
 network 192.168.12.0 0.0.0.255 area 0
 network 192.168.23.0 0.0.0.255 area 0
router bgp 2
 bgp log-neighbor-changes
 network 2.2.2.0 mask 255.255.255.0
 network 22.22.22.0 mask 255.255.255.0
 neighbor 1.1.1.1 remote-as 1
 neighbor 1.1.1.1 ebgp-multihop 2
 neighbor 1.1.1.1 update-source Loopback0
 neighbor 3.3.3.3 remote-as 3
 neighbor 3.3.3.3 ebgp-multihop 2
 neighbor 3.3.3.3 update-source Loopback0

the more i get used to bgp, the more i'm beginning to like it...