R1(config-if)#ip add 10.1.12.1
255.255.255.0
R1(config-if)#no sh
R1(config)#int lo0
R1(config-if)#ip add 1.1.1.1
255.255.255.255
R1(config-if)#exit
R1(config)#router bgp 1
R1(config-router)#nei 10.1.12.2
remote-as 1
R1(config-router)#nei 10.1.23.3
remote-as 1
R1(config-router)#nei 10.1.34.4
remote-as 1
R1(config-router)#network 1.1.1.1
mask 255.255.255.255
R1(config-router)#end
R1#conf t
R1(config)#ip route 10.1.23.0
255.255.255.0 10.1.12.2
R1(config)#ip route 10.1.34.0
255.255.255.0 10.1.12.2
R1(config)#end
R2(config)#int f0/0
R2(config-if)#ip add 10.1.12.2
255.255.255.0
R2(config-if)#no sh
R2(config)#int f1/0
R2(config-if)#ip add 10.1.23.2
255.255.255.0
R2(config-if)#no sh
R2(config)#int lo0
R2(config-if)#ip add 2.2.2.2
255.255.255.255
R2(config-if)#exit
R2(config)#router bgp 1
R2(config-router)#nei
10.1.12.1 remote-as 1
R2(config-router)#nei
10.1.23.3 remote-as 1
R2(config-router)#net 2.2.2.2
mask 255.255.255.255
R2(config-router)#end
R2#conf t
R2(config)#ip route 10.1.34.0
255.255.255.0 10.1.23.3
R2(config)#end
R3(config)#int f0/0
R3(config-if)#ip add 10.1.23.3
255.255.255.0
R3(config-if)#no sh
R3(config)#int f1/0
R3(config-if)#ip add 10.1.34.3
255.255.255.0
R3(config-if)#no sh
R3(config)#int lo0
R3(config-if)#ip add 3.3.3.3
255.255.255.255
R3(config-if)#exit
R3(config)#router bgp 1
R3(config-router)#nei
10.1.23.2 remote-as 1
R3(config-router)#nei
10.1.34.4 remote-as 1
R3(config-router)#net 3.3.3.3
mask 255.255.255.255
R3(config-router)#end
R3(config)#ip route
R3(config)#ip route 10.1.12.0
255.255.255.0 10.1.23.2
R3(config)#end
R4(config)#int f0/0
R4(config-if)#ip add 10.1.34.4
255.255.255.0
R4(config-if)#no sh
R4(config)#int lo0
R4(config-if)#ip add 4.4.4.4
255.255.255.255
R4(config-if)#exit
R4(config)#router bgp 1
R4(config-router)#nei
10.1.34.3 remote-as 1
R4(config-router)#net 4.4.4.4
mask 255.255.255.255
R4(config-router)#end
R4#conf t
R4(config)#ip route 10.1.23.0
255.255.255.0 10.1.34.3
R4(config)#ip route 10.1.12.0
255.255.255.0 10.1.34.3
R4(config)#end
R1#sh ip bgp
BGP table version is 5, 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
Origin codes: i - IGP, e - EGP, ? - incomplete
Network Next Hop Metric LocPrf Weight
Path
*> 1.1.1.1/32
0.0.0.0 0
32768 i
*>i2.2.2.2/32
10.1.12.2 0 100
0 i
*>i3.3.3.3/32
10.1.23.3 0
100 0 i
*>i4.4.4.4/32
10.1.34.4 0 100
0 i
R1#sh ip bgp summ
BGP router identifier
1.1.1.1, local AS number 1
BGP table version is 5, main
routing table version 5
4 network entries using 468
bytes of memory
4 path entries using 208
bytes of memory
3/2 BGP path/bestpath
attribute entries using 372 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 1048 total bytes of
memory
BGP activity 4/0 prefixes,
6/2 paths, scan interval 60 secs
Neighbor V
AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/PfxRcd
10.1.12.2 4
1 39 39
5 0 0 00:32:36 1
10.1.23.3 4
1 18 18
5 0 0 00:13:14 1
10.1.34.4 4
1 16 16
5 0 0 00:11:30 1
R1#sh ip route
Codes: C - connected, S -
static, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O -
OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 -
OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF
external type 2
i - IS-IS, su - IS-IS summary, L1 -
IS-IS level-1, L2 - IS-IS level-2
ia - IS-IS inter area, * - candidate
default, U - per-user static route
o - ODR, P - periodic downloaded static
route
Gateway of last resort is not
set
1.0.0.0/32 is subnetted, 1 subnets
C 1.1.1.1 is directly connected, Loopback0
2.0.0.0/32 is subnetted, 1 subnets
B 2.2.2.2 [200/0] via 10.1.12.2, 00:33:43
3.0.0.0/32 is subnetted, 1 subnets
B 3.3.3.3 [200/0] via 10.1.23.3, 00:15:21
4.0.0.0/32 is subnetted, 1 subnets
B 4.4.4.4 [200/0] via 10.1.34.4, 00:13:36
10.0.0.0/24 is subnetted, 3 subnets
C 10.1.12.0 is directly connected,
FastEthernet0/0
S 10.1.23.0 [1/0] via 10.1.12.2
S 10.1.34.0 [1/0] via 10.1.12.2
R1#sh tcp bri
TCB Local Address Foreign Address (state)
64FBD584 10.1.12.1.40937 10.1.12.2.179 ESTAB
64FBCF34 10.1.12.1.179 10.1.34.4.29315 ESTAB
64FC1788 10.1.12.1.179 10.1.23.3.59782 ESTAB
R1#ping
10.1.34.4
Type escape sequence to
abort.
Sending 5, 100-byte ICMP
Echos to 10.1.34.4, timeout is 2 seconds:
!!!!!
Success rate is 100 percent
(5/5), round-trip min/avg/max = 56/64/68 ms
R1#ping
4.4.4.4
Type escape sequence to
abort.
Sending 5, 100-byte ICMP
Echos to 4.4.4.4, timeout is 2 seconds:
!!!!!
Success rate is 100 percent
(5/5), round-trip min/avg/max = 56/64/68 ms
R2#sh ip bgp
BGP table version is 5, local
router ID is 2.2.2.2
Status codes: s suppressed, d
damped, h history, * valid, > best, i - internal,
r RIB-failure, S Stale
Origin codes: i - IGP, e -
EGP, ? - incomplete
Network Next Hop Metric LocPrf Weight Path
*>i1.1.1.1/32 10.1.12.1 0 100 0 i
*> 2.2.2.2/32 0.0.0.0 0
32768 i
*>i3.3.3.3/32 10.1.23.3 0 100 0 i
*>i4.4.4.4/32 10.1.34.4 0 100 0 i
R3#sh ip bgp
BGP table version is 5, local
router ID is 3.3.3.3
Status codes: s suppressed, d
damped, h history, * valid, > best, i - internal,
r RIB-failure, S Stale
Origin codes: i - IGP, e -
EGP, ? - incomplete
Network Next Hop Metric LocPrf Weight
Path
*>i1.1.1.1/32 10.1.12.1 0 100 0 i
*>i2.2.2.2/32 10.1.23.2 0 100 0 i
*> 3.3.3.3/32 0.0.0.0 0
32768 i
*>i4.4.4.4/32 10.1.34.4 0 100 0 i
R4#sh ip bgp
BGP table version is 5, local
router ID is 4.4.4.4
Status codes: s suppressed, d
damped, h history, * valid, > best, i - internal,
r RIB-failure, S Stale
Origin codes: i - IGP, e -
EGP, ? - incomplete
Network Next Hop Metric LocPrf Weight Path
*>i1.1.1.1/32 10.1.12.1 0 100 0 i
*>i2.2.2.2/32 10.1.23.2 0 100 0 i
*>i3.3.3.3/32 10.1.34.3 0 100 0 i
*> 4.4.4.4/32 0.0.0.0 0
32768 i