Hello friends
I am in need of a help.
I am currently working on a setup for a client. Topology is simple. There are 2 sites connected together over 2 P2P links. These are both layer 2 links.
I recently replaced their EoL cisco 3500 switches ( 4 they had ) with 2 ISR 4300 to act as their routers and 2 3750 for one of the P2P links.
See below diagram :
CE1:
int BDI 666
encapsulation dot1Q 666
ip address 192.168.1.1 255.255.255.0
!
interface GigabitEthernet0/0/2
service instance 666 ethernet
encapsulation dot1q 666
rewrite ingress tag pop 1 symmetric
bridge-domain 666
!
interface GigabitEthernet0/0/0
service instance 666 ethernet
encapsulation dot1q 2100 second-dot1q 666
rewrite ingress tag pop 2 symmetric
bridge-domain 666
l2ptotocol peer
!
spanning-tree mode pvst
spanning-tree extend system-id
spanning-tree vlan 666 priority 24576
!
CE2:
int vlan 666
ip add 192.168.1.2 255.255.255.0
!
int f 0/1
sw mod trunk
sw trunk allowed vlan 666
!
spanning-tree mode pvst
spanning-tree extend system-id
spanning-tree vlan 666 priority 20480
!
interface G 0/2
sw mod trunk
sw trunk allowed vlan none
!
CE3:
int vlan 666
ip add 192.168.1.3 255.255.255.0
!
int f 0/1
sw mod trunk
sw trunk allowed vlan 666
!
spanning-tree mode pvst
spanning-tree extend system-id
spanning-tree vlan 666 priority 12350
!
interfave gi 0/2
sw mod trunk
sw trunk allowed vlan none
CE4:
int BDI 666
encapsulation dot1Q 666
ip address 192.168.1.4 255.255.255.0
!
interface GigabitEthernet0/0/2
service instance 666 ethernet
encapsulation dot1q 666
rewrite ingress tag pop 1 symmetric
bridge-domain 666
!
interface GigabitEthernet0/0/0
service instance 666 ethernet
encapsulation dot1q 2100 second-dot1q 666
rewrite ingress tag pop 2 symmetric
bridge-domain 666
l2ptotocol peer
!
spanning-tree mode pvst
spanning-tree extend system-id
spanning-tree vlan 666 priority 8192
!
All works great at the moment as the link between CE2 and CE3 is not allowing vlan 666.
I can ping all 4 devices from everywhere.
As soon as I allow the vlan through the trunk between CE2 and CE3 , I see a loop ( mac address flap ) and I lose the network.
I allowed it for 30second to make sure it is not spanning tree sorting itself out, but no, kept getting the message.
So I am at a bit of a loss as I seem to have followed the setup guides I have seen here but still getting the issue
It should be noted that if I issue the command:
sh spanning-tree vlan 666 on the ISR, I only see the G0/0/2 being listed in the output and not gi 0/0/0.
but if I do sh spanning-tree bridge, then I see
vlan666
vlan2200
and I can't see the status of the port to see if it is forwarding or blocking or ... when I use the command sh spanning-tree bridge
Any help will be appreciated as I am struggling with this and time is noton my side.
Thanks
