We have a 3750 and a 3560 defined as a layer 2 switches. One gig port on each switch is trunked to layer 3 switches, which contain
all the VLAN definitions etc. The other gig port on the 3650 and 3750 switches are trunked together to provide an alternative path in the
event of a failure.
We have added a new device to the 3750 and given it a VLAN 9, and the VLAN added to allowable VLANS on both trunk
ports between the layer 3 and layer 2 devices ie:
switchport trunk allowed vlan 9,10,20,30,40,50,60,90,200,202,206,211,212,700.
From either of the 3750 or the 3560 we can ping any device on any VLAN on any switch in this group with exception of
VLAN 9. We can however ping the ip address of VLAN 9 on the layer three switches.
Output from "sh int trunk" on the 3560 is as follows. Gig0/1 goes to the 3750, gig0/2 to the layer 3 switch:
Port Mode Encapsulation Status Native vlan
Gi0/1 on 802.1q trunking 1
Gi0/2 on 802.1q trunking 1
Port Vlans allowed on trunk
Gi0/1 9-10,20,30,40,50,60,90,202,206,211-212,700
Gi0/2 9-10,20,30,40,50,60,90,202,206,211-212,700
Port Vlans allowed and active in management domain
Gi0/1 10,20,40,50,60,90,202,206,211-212,700
Gi0/2 10,20,40,50,60,90,202,206,211-212,700
Port Vlans in spanning tree forwarding state and not pruned
Gi0/1 10,20,40,50,60,90,202,206,700
Gi0/2 10,20,40,50,60,90,202,206,211-212,700
Output from "sh int trunk" on the 3750 is as follows, gig1/0/1 goes to the layer 3 switch and gig1/0/2 goes to the 3560:
Port Mode Encapsulation Status Native vlan
Gi1/0/1 on 802.1q trunking 1
Gi1/0/2 on 802.1q trunking 1
Port Vlans allowed on trunk
Gi1/0/1 9-10,20,30,40,50,60,90,200,202,206,211-212,700
Gi1/0/2 9-10,20,30,40,50,60,90,200,202,206,211-212,700
Port Vlans allowed and active in management domain
Gi1/0/1 9-10,20,40,50,60,90,200,202,206,211-212,700
Gi1/0/2 9-10,20,40,50,60,90,200,202,206,211-212,700
Port Vlans in spanning tree forwarding state and not pruned
Gi1/0/1 9-10,20,40,50,60,90,200,202,206,211-212,700
Gi1/0/2 9-10,20,40,50,60,90,200,211-212,700
I am curious why the descrepancy between the two switched when it comes to the "forwarding state" entry. VLAN 9 does not show up on the 3560 even though it is defined on the port. I am not sure if this is the problem or not. Lost for ideas at the moment why one cannot ping
we cannot ping any device on VLAN 9.
There is another device on VLAN 9 which is pingable for the other switches, but not from this closet.
Thanks
