L2vpn with vlan swap not working. Cisco and Juniper interop.

James Lasky · ‎02-11-2009

Hi

I made a Ethernet l2vpn over my MPLS network (with PE Juniper M320).

The PE (M320) is connected in both sides with a Cisco switch and behind a router.

This is the net design

[router-a]--<v141>--[sw1]--<trunk>--[m320]--MPLS--[m320]--<trunk>--[sw2]--<trunk>--[sw3]--<v185> --[router-b]

The problem: if I keep the same vlan-id in both side it works without problems, if it's needed a different vlan (ie in the net design I put v141 and v185) and I config vlan swapping in the juniper interface (802.1q-ccc), in the remote Cisco switch I get a pvst+ problem:

#sh spanning-tree vlan 185

VLAN0185

Spanning tree enabled protocol ieee

Root ID Priority 32768

Address 0003.6b09.44b8

Cost 4

Port 3 (GigabitEthernet1/3)

Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec

Bridge ID Priority 32953 (priority 32768 sys-id-ext 185)

Address 001f.9e79.4f00

Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec

Aging Time 300

Interface Role Sts Cost Prio.Nbr Type

------------------- ---- --- --------- -------- --------------------------------

Gi8/1 Desg BKN*4 128.449 P2p *PVID_Inc ïƒŸ--- this is the trunk between switch and M320 in site-b

Any idea ?

Tks

Ric

Mohamed Sobair · ‎02-11-2009

HI,

With L2VPN Draft Martini (Circuit Cross Connect) Vlan swapping , u shouldnt have such a problem. what should happen is that traffic tagged with 185 is swapped with 141 at M320 and vice versa. The question is why u are doing Vlan Swapping here??

Pls clarify more..

Mohamed

James Lasky · ‎02-11-2009

Hi Mohamed

the reason since I'm doing swapping is that my customer has in site1 vlan 141 and in site2 vlan 185 and wants an additional lan extension... (if it was my decision I'd use the same vlan)

In cisco.com I found this:

-----------------

Error Message SPANTREE-2-RX_1QPVIDERR: Rcved pvid_inc BPDU on 1Q

port [chars] vlan [dec]

Explanation This message indicates that the 1Q-trunking port has received at least one 1Q-tagged spantree Bridge Protocol Data Unit (BPDU) frame with an inconsistent transmitting VLAN ID to the receiving port VLAN ID. [chars] is the module number/port number and [dec] is the VLAN number.

Recommended Action Either reconfigure the receiving port VLAN ID to the same VLAN ID of the peer port, or reconfigure the peer port VLAN ID to the same VLAN ID of the receiving port.

-----------------

But this cannot be the solution.

Tks

Ric

James Lasky · ‎02-11-2009

Hi Mohamed

the reason since I'm doing swapping is that my customer has in site1 vlan 141 and in site2 vlan 185 and wants an additional lan extension... (if it was my decision I'd use the same vlan)

In cisco.com I found this:

-----------------

Error Message SPANTREE-2-RX_1QPVIDERR: Rcved pvid_inc BPDU on 1Q

port [chars] vlan [dec]

Explanation This message indicates that the 1Q-trunking port has received at least one 1Q-tagged spantree Bridge Protocol Data Unit (BPDU) frame with an inconsistent transmitting VLAN ID to the receiving port VLAN ID. [chars] is the module number/port number and [dec] is the VLAN number.

Recommended Action Either reconfigure the receiving port VLAN ID to the same VLAN ID of the peer port, or reconfigure the peer port VLAN ID to the same VLAN ID of the receiving port.

-----------------

But this cannot be the solution.

Tks

Ric

Mohamed Sobair · ‎02-11-2009

Hi Ric,

Although this is not the correct approach for designing a LAN extension, d I really dont know What extension u would accomplish here?? U mainely merging between Vlans , This approach is typically done when u want to Isolate different Customer's Vlans or Migrating but it shouldnt be the Optimal.

However, Spanning tree is blocking vlan 185 on that port, Do u have any redundant link towards the M320? what is the allowed Vlans on that Port as well as the peer trunking port?

Mohamed

James Lasky · ‎02-11-2009

Hi Mohamed,

no redundant link are in place.

SPT is blocking (blk) due to vlan inconsistancy (bkn --> broken).

No vlan filter is in place.

Ric