VLAN Issue

2811 connected to 3548. Simple, but one VLAN fails. I have adopted a network and have seen this config before as on the switch port below but cannot recall what effect it has or why it would be done this way.

All VLANS below work fine except VLAN 5

Machines in VLAN 5 are all connected to the switch

Router interface to switch config ====================== interface GigabitEthernet0/0 description Handoff to lonrhs1 (Redbus LAN) no ip address duplex full speed 100

interface GigabitEthernet0/0.19 encapsulation dot1Q 19 ip address 99.12.23.1 255.255.255.0 ! interface GigabitEthernet0/0.22 encapsulation dot1Q 22 ip address 99.12.1.172 255.255.255.248 ! interface GigabitEthernet0/0.816 encapsulation dot1Q 816 ip address 99.12.48.62 255.255.255.252

interface GigabitEthernet0/0.5 encapsulation dot1Q 5 ip address 99.12.0.129 255.255.255.248

Switch port to router ============== interface FastEthernet0/45 duplex full speed 100 switchport access vlan 3 switchport trunk encapsulation dot1q switchport trunk native vlan 3 switchport trunk allowed vlan 1,3,5,12,14,17-19,22,60,642,691,692,816 switchport trunk allowed vlan add 1002-1005 switchport mode trunk !

I Have seen trunks where the vlan and native vlan are the same and from memory I think it fully negates the VLAN and makes it a regular trunk??? but I cannot see why other VLANS work fine but VLAN 5 cannot see the machines on the switch.

Anyway to debug or check would be appreciated. Gary

Gary,

You a LOT of conflicting config that does not need to be included, Let's try to make your life a LOT easier...

First off... There doesn't need to be a "native" vlan. A truck is simply just a connection that will use an encap. method to transport multiple vlan's traffic across it self. A Truck port should NOT have a switchport access vlan...

Switch port to router ============== interface FastEthernet0/45 duplex full speed 100 Remove > switchport access vlan 3 switchport trunk encapsulation dot1q Remove > switchport trunk native vlan 3 switchport trunk allowed vlan 1,3,5,12,14,17-19,22,60,642,691,692,816 switchport trunk allowed vlan add 1002-1005 switchport mode trunk !

When configuring a truck, Choose the truck port (physical, port-group, it doesn't matter) include your basic interface controls then all you need is the following:

switchport trunk encap dot1q switchport mode trunk

That is it... If you desire to LIMIT the VLAN's that can travel across the link then you have two options:

explicitly name the VLAN's that are permitted on the trunk. (switchport trunk allowed vlan add/remove)
deploy Vlan Pruning...

Start there... and I will try to get more to you later.