my topology is like that:
vlan 30 - router A & B - mpls cloud (no vlans) - router C & D - vlan 30
I've created two xconnect tunnels (A-C and B-D), but the first is working, the second is for a cold backup.
How could I use both at the same time? Maybe I've to transport the BPDUs, to loop prevention, but how? Any advice will be appreciated
May be you want to use Layer 2 Protocol Tunneling, with two independent VC's carrying the same vlan between the end points.
Switch(config)# interface gigabitethernet1/0/2
Switch(config-if)# Description Customer Facing Trunk
Switch(config-if)# l2protocol-tunnel stp
Switch(config-if)# switchport mode dot1q-tunnel
Switch(config-if)# switchport access vlan 30
Switch(config)# interface vlan30
Switch(config-if)# mpls l2transport route
You may try it this way, modifying the config as per your existing setup.
thanks for your answer, I've tried but I've a problem with BPDU transport.
In effect, I see both PE root bridge for vlan30, so I think BPDU transport doesn't work
PE-TEST-A and PE-TEST-B
PE-TEST-A would be the root bridge:
spanning-tree vlan 30 priority 24576
the tunnel is up, the SVI is up, but the sh span sum says both are the root bridge (my expectation was "Root port" on PE-TEST-B)!
Any advice will be appreciated
L2PT sounds really interesting!!
I wanted to create a scenario to learn it better.
What I am thinking is to connect a router(acting as a host) to a 3550 and the 3550 to a MPLS PE(3640) router, across to the other side and similiar setup on the other side.
Does it make any sense?
Niraj & Andrea, the 3550 supports QinQ with L2Protocol Tunneling.
Here is the feature configuration guide.
Andrea, Customer STP can be transported across the MetroCore encapsulated in the L2Prot_Tunnel end-to-end,
can you illustrate or explain your topology and the objective, so we can understand the problem.
first of all, thanks for your support, it is very appreciated.
Well, about the shows in my last post, the topology of my first lab was like this:
CE-TEST-A and CE-TEST-B connected to PEs, and on vlan 30; l2transport between PEs.
I've changed the priority on PE-TEST-A, so that PE could be the root bridge for the vlan 30. But when all is ok, I see both PEs root bridges for the same vlan 30. My expectation was PE-TEST-B with a 'root port' instead of 'designated port', correct?
Andrea, you should do a QinQ with L2Tunnel to transport the BPDU of the customer transparently via the core to the other customer end.(CE-MetroE Core-CE)
Your core should be transparent to the SP core as a best practise, to avoid complications with you VLAN addressing and your STP design.
So if your CE is connected to your PE on vlan 30 then on the port connecting to the CE on the PE you do a QinQ and do a L2transport for the SP vlan and also a L2protocol transport on the interface, so it carries the L2 protocol frames received from your CE to the other side CE.
If you want to do something else apart from transporting BPDU's from the CE then do elaborate.
thanks for your answer, I've forgotten, and maybe it's important: I work for this SP, so PEs and P are on my hand ... the MPLS core hasn't vlans, all is label based. So, is it possible to create this?
The configuration that I've applied is like this:
switchport mode dot1q-tunnel
switchport access vlan 30
mpls l2transport route
Any advice will be appreciated
Andrea, yes definately this will work.
This will transport the customer L2 protocol packets to the other side including the STP.
So the CE's at each end can run STP between themselves. PE's wont be involved in this STP at all. So do not enable STP for vlan 30 on the PE's. As they are just carrier Vlans.
so, if I've well understood, is it normal that I see on PEs both ports "designated" and not "des/root"? I've to check the STP on CEs, and not on PEs. How could I check if the STP works correctly at each end?
Thanks again for your support
Andrea, since you are using a L2transport, the PE's would be L3 peers, so do not enable STP between the PE's.
And if you are seeing a designated port then its normal, as each PE will consider itself the root for Vlan which it is transporting to the other side.
Designated-Root role in your topology means a problem, which will signify some one else is the root.
Now coming to your CE, to check STP is working fine or not try to manipulate the STP Bridge priority and see the effect for common Vlans spanning tree root ID. the root ID shoudl be the bridge ID of the switch whose priority you reduced.
Please do let me know if you have any more questions.
thanks for your support.
So, maybe a stupid question, but ... if I change the STP priority on vlan 30 "A side", I'll see something on STP vlan 30 "B side"?
Andrea, Yes if you change the root parameters on CE-A side you should see the effect on CE-B side.
If you dont see this happening then check you L2protocol tunneling once again.