R1 ---- R2 ---- R3 ---- R4 ---- R5
 00    01 00   01 00   01 00   01

R1 ---- sw15 ---- R5

R1 fa0/1: 10.10.15.1/24
R1 fa0/0: 10.10.12.1/24
R1 lo0: 1.1.1.1/32
PC 3Com: 10.10.15.11/24

R2 fa0/1: 10.10.12.2/24
R2 fa0/0: 10.10.23.2/24
R2 lo0: 2.2.2.2/24
PC 3Com: 10.10.15.12/24

R3 fa0/1: 10.10.23.3/24
R3 fa0/0: 10.10.34.3/24
R3 lo0: 3.3.3.3/32
PC 3Com: 10.10.15.13/24

R4 fa0/1: 10.10.34.4/24
R4 fa0/0: 10.10.45.4/24
R4 lo0: 4.4.4.4/32
PC 3Com: 10.10.15.14/24

R5 fa0/1: 10.10.45.5/24
R5 fa0/0: 10.10.15.5/24
R5 lo0: 5.5.5.5/32
PC 3Com: 10.10.15.15/24

sh cdp nei
sh cdp net det
sh ip int br
sh run
sh start
wr
copy run start

make the fa0/1 of your neighbor your default gateway
R1(config)#ip route 0.0.0.0 0.0.0.0 10.10.12.2 

conf t
line vty 0 4
no login
privi level 15