r#show run

interface Loopback0
 ip address 10.200.2.1 255.255.255.0
!
interface FastEthernet0/0
 ip address 10.200.1.2 255.255.255.0
 no sh
!
router eigrp 100
 network 10.0.0.0
 no auto-summary
!        
end

3550#show run

interface FastEthernet1/2
 switchport mode trunk
 no sh
!        
interface FastEthernet1/15
 no switchport
 ip address 10.200.1.1 255.255.255.0
!
interface Vlan1
 ip address 172.16.1.1 255.255.255.0
!
interface Vlan10
 ip address 172.16.10.1 255.255.255.0
!
interface Vlan20
 ip address 172.16.20.1 255.255.255.0
!
router eigrp 100
 network 10.0.0.0
 network 172.16.0.0
 no auto-summary
!
!

2950#show run

interface FastEthernet1/1
 switchport mode trunk
 no sh
!
interface FastEthernet1/11
 switchport access vlan 10
 no sh
!
interface FastEthernet1/12
 switchport access vlan 20
 no sh
!
interface FastEthernet1/13
 switchport access vlan 10
 no sh
!
interface Vlan1
 no ip address
 no sh

 

pc1#show run

interface FastEthernet0/0
 ip address 172.16.10.2 255.255.255.0
 no sh
ip route 0.0.0.0 0.0.0.0 172.16.10.1

pc2#show run
!
interface FastEthernet0/0
 ip address 172.16.20.2 255.255.255.0
 no sh
ip route 0.0.0.0 0.0.0.0 172.16.20.1        
!    

PC3#sho run
!
interface FastEthernet0/0
 ip address 172.16.10.3 255.255.255.0
 no sh
ip route 0.0.0.0 0.0.0.0 172.16.10.1
!