cat3550 f0/2 configured with one access vlan 20 and one voice vlan 50 f0/1 access vlan 50 f0/3 access vlan 20
r1-2 configured with a native vlan 20 and a dot1q trunk vlan 50 (simulating ip phone)
And ping r1-1 and r1-3 works from r1-2!
This means that cat3550 treats the voice vlan in a very special way!
If you configure the voice vlan port as a dot1q trunk port, you may need to block all vlans other than the native vlan and voice vlan. Otherwise all other vlan packets will be sent to the ip phone...
interface FastEthernet0/1 switchport access vlan 50 no ip address ! interface FastEthernet0/2 switchport access vlan 20 switchport voice vlan 50 no ip address duplex full speed 100 spanning-tree portfast ! interface FastEthernet0/3 switchport access vlan 20 no ip address ! =============
r1-1: interface Ethernet0/0 ip address 50.1.1.10 255.255.255.0
r1-2:
interface FastEthernet0/0 no ip address speed 100 full-duplex ! interface FastEthernet0/0.20 encapsulation dot1Q 20 native ip address 20.1.1.1 255.255.255.0 ! interface FastEthernet0/0.50 encapsulation dot1Q 50 ip address 50.1.1.1 255.255.255.0 !
r1-3: interface Ethernet0 ip address 20.1.1.3 255.255.255.0 no ip directed-broadcast !
r1-2#p 20.1.1.3
Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 20.1.1.3, timeout is 2 seconds: !!!!! SUCcess rate is 100 percent (5/5), round-trip min/avg/max = 1/2/4 ms
r1-2#p 50.1.1.10
Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 50.1.1.10, timeout is 2 seconds: !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 1/2/4 ms
