beware the red knight...

if you're beyond this, go haunt another...

basic bgp...

ibgp

as100b#sh run | beg router
router bgp 100
 bgp log-neighbor-changes
 neighbor 10.1.1.1 remote-as 100

as100a#sh run | beg router
router bgp 100
 bgp log-neighbor-changes
 neighbor 10.1.1.2 remote-as 100

as100a#sh ip bgp neigh | inc BGP
BGP neighbor is 10.1.1.2,  remote AS 100, internal link
  BGP version 4, remote router ID 10.1.1.2
  BGP state = Established, up for 00:05:11
  BGP table version 1, neighbor version 1/0

as100b#sh ip bgp neigh | inc BGP
BGP neighbor is 10.1.1.1,  remote AS 100, internal link
  BGP version 4, remote router ID 10.1.1.1
  BGP state = Established, up for 00:07:44
  BGP table version 1, neighbor version 1/0





as100a#sh ip route

Gateway of last resort is not set

      10.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
C        10.1.1.0/24 is directly connected, Serial1/1
L        10.1.1.1/32 is directly connected, Serial1/1
as100a#ping 10.1.1.2
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 10.1.1.2, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 4/4/4 ms

with loopback...

as100a#sh run | begin router
router bgp 100
 bgp log-neighbor-changes
 neighbor 2.2.2.2 remote-as 100
 neighbor 2.2.2.2 update-source Loopback0

as100b#sh run | beg router
router bgp 100
 bgp log-neighbor-changes
 neighbor 1.1.1.1 remote-as 100
 neighbor 1.1.1.1 update-source Loopback0

as100a#sh ip bgp neigh | incl BGP
BGP neighbor is 2.2.2.2,  remote AS 100, internal link
  BGP version 4, remote router ID 0.0.0.0
  BGP state = Idle
  BGP table version 1, neighbor version 1/0

ip route 2.2.2.2 255.255.255.255 10.1.1.2

ip route 1.1.1.1 255.255.255.255 10.1.1.1

as100b(config)#ip route 1.1.1.1 255.255.255.255 10.1.1.1
as100b(config)#end
as100b#
*Aug 26 17:44:25: %BGP-5-ADJCHANGE: neighbor 1.1.1.1 Up
as100b#
*Aug 26 17:44:26: %SYS-5-CONFIG_I: Configured from console by console
as100b#sh ip bgp neigh | inc BGP
BGP neighbor is 1.1.1.1,  remote AS 100, internal link
  BGP version 4, remote router ID 1.1.1.1
  BGP state = Established, up for 00:00:23
  BGP table version 1, neighbor version 1/0

as100a#ping 10.1.1.2
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 10.1.1.2, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 4/4/4 ms
as100a#ping 2.2.2.2
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 2.2.2.2, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 4/4/8 ms

as100a#sh ip bgp summ
BGP router identifier 1.1.1.1, local AS number 100
BGP table version is 1, main routing table version 1

Neighbor        V           AS MsgRcvd MsgSent   TblVer  InQ OutQ Up/Down  State/PfxRcd
2.2.2.2         4          100       9       9        1    0    0 00:04:40        0
as100a#

ebgp with loopback...

as100#sh run | begin router
router bgp 100
 bgp log-neighbor-changes
 neighbor 2.2.2.2 remote-as 200
 neighbor 2.2.2.2 ebgp-multihop 2
 neighbor 2.2.2.2 update-source Loopback0

as200#sh run | beg router
router bgp 200
 bgp log-neighbor-changes
 neighbor 1.1.1.1 remote-as 100
 neighbor 1.1.1.1 ebgp-multihop 2
 neighbor 1.1.1.1 update-source Loopback0

the ttl value is two on ebgp-multihop because it is not directly connected...

as200#sh ip bgp neigh | incl BGP
BGP neighbor is 1.1.1.1,  remote AS 100, external link
  BGP version 4, remote router ID 1.1.1.1
  BGP state = Established, up for 00:05:34
  BGP table version 1, neighbor version 1/0
  External BGP neighbor may be up to 2 hops away.

as100#ping 2.2.2.2
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 2.2.2.2, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 4/4/8 ms
as100#

sometimes you just gotta keep backing up...