Tunel GRE

R1#sh run int s0/0
interface Serial0/0
 ip address 10.10.10.1 255.255.255.252
 clock rate 2000000
end

interface FastEthernet0/0
 ip address 192.168.10.254 255.255.255.0
 duplex auto
 speed auto
end

interface Tunnel0
 ip address 172.16.0.1 255.255.255.0
 tunnel source 10.10.10.1
 tunnel destination 10.10.10.6
end

router ospf 1
 network 172.16.0.0 0.0.0.255 area 0
 network 192.168.10.0 0.0.0.255 area 0

R3#

interface Serial0/0
 ip address 10.10.10.6 255.255.255.252
 clock rate 2000000
interface FastEthernet0/0
 ip address 192.168.20.254 255.255.255.0
 duplex auto
 speed auto
end

interface Tunnel0
 ip address 172.16.0.3 255.255.255.0
 tunnel source 10.10.10.6
 tunnel destination 10.10.10.1
end

router ospf 1
 log-adjacency-changes
 network 172.16.0.0 0.0.0.255 area 0
 network 192.168.20.0 0.0.0.255 area 0

  ping de la Pc1 a la Pc2
  ping 192.168.168.20.10