My L2TPv3 peering setup is using 2 Cisco 1841 routers and is working. Spanning-tree PVST is peering across the L2TPv3 tunnel, the head-end is the root for the 3 Vlans. Each Cisco 1841 router interfaces with a Cisco 3750 switch. The router & switch (at each end) interface via an 802.1q trunk.
Topology:
(Host1&2)__3750-1===trunk====1841-1--------L2TPv3-------1841-2=====trunk=====3750-2__(Host3&4)
Native Vlan 500
Host 1 Vlan 555
Host 2 Vlan 556
We want (need) to upgrade to spanning-tree MST but noticed during this change the MST domains remain isolated at each end. We suspect that since the Cisco 1841 routers do not support MST; these routers are creating a spanning-tree domain boundary.
Anyone know if this IS the case or have any suggestions to support MST across the L2TPv3 tunnel?
Thanks Frank
L2TPv3-1# sh l2tun tunn all
L2TP Tunnel Information Total tunnels 2 sessions 2
Tunnel id 259422696 is up, remote id is 3674041411, 1 active sessions
Locally initiated tunnel
Tunnel state is established, time since change 1d22h
Tunnel transport is IP (115)
Remote tunnel name is L2TPv3-2
Internet Address 192.168.0.5, port 0
Local tunnel name is L2TPv3-1
Internet Address 192.168.0.1, port 0
L2TP class for tunnel is 555
Counters, taking last clear into account:
77553 packets sent, 116125 received
5323208 bytes sent, 8269418 received
Last clearing of counters never
Counters, ignoring last clear:
77553 packets sent, 116125 received
5323208 bytes sent, 8269418 received
Control Ns 14, Nr 16792
Local RWS 1024 (default), Remote RWS 1024
Control channel Congestion Control is disabled
Tunnel PMTU checking disabled
Retransmission time 1, max 1 seconds
Unsent queuesize 0, max 0
Resend queuesize 0, max 2
Total resends 2, ZLB ACKs sent 16791
Total out-of-order dropped pkts 0
Total out-of-order reorder pkts 0
Total peer authentication failures 0
Current no session pak queue check 0 of 5
Retransmit time distribution: 0 1 1 0 0 0 0 0 0
Control message authentication is disabled
Tunnel id 3905588394 is up, remote id is 3875190023, 1 active sessions
Locally initiated tunnel
Tunnel state is established, time since change 1d22h
Tunnel transport is IP (115)
Remote tunnel name is L2TPv3-2
Internet Address 192.168.0.6, port 0
Local tunnel name is L2TPv3-1
Internet Address 192.168.0.2, port 0
L2TP class for tunnel is 556
Counters, taking last clear into account:
79998 packets sent, 113345 received
5489237 bytes sent, 8070888 received
Last clearing of counters never
Counters, ignoring last clear:
79998 packets sent, 113345 received
5489237 bytes sent, 8070888 received
Control Ns 15, Nr 16794
Local RWS 1024 (default), Remote RWS 1024
Control channel Congestion Control is disabled
Tunnel PMTU checking disabled
Retransmission time 1, max 1 seconds
Unsent queuesize 0, max 0
Resend queuesize 0, max 3
Total resends 2, ZLB ACKs sent 16791
Total out-of-order dropped pkts 0
Total out-of-order reorder pkts 0
Total peer authentication failures 0
Current no session pak queue check 0 of 5
Retransmit time distribution: 0 1 1 0 0 0 0 0 0
Control message authentication is disabled
L2TPv3-1#
L2TPv3-1# sh spanning-tree
No spanning tree instances exist.
3750-1# sh span mst
##### MST0 vlans mapped: 1-554,557-4094
Bridge address 0013.8072.1a00 priority 4096 (4096 sysid 0)
Root this switch for the CIST
Operational hello time 2 , forward delay 15, max age 20, txholdcount 6
Configured hello time 2 , forward delay 15, max age 20, max hops 20
Interface Role Sts Cost Prio.Nbr Type
---------------- ---- --- --------- -------- --------------------------------
Fa1/0/16 Desg BKN*200000 128.18 P2p Bound(PVST) *PVST_Inc
##### MST1 vlans mapped: 555
Bridge address 0013.8072.1a00 priority 1 (0 sysid 1)
Root this switch for MST1
Interface Role Sts Cost Prio.Nbr Type
---------------- ---- --- --------- -------- --------------------------------
Fa1/0/16 Desg BKN*200000 128.18 P2p Bound(PVST) *PVST_Inc
##### MST2 vlans mapped: 556
Bridge address 0013.8072.1a00 priority 16386 (16384 sysid 2)
Root this switch for MST2
Interface Role Sts Cost Prio.Nbr Type
---------------- ---- --- --------- -------- --------------------------------
Fa1/0/16 Desg BKN*200000 128.18 P2p Bound(PVST) *PVST_Inc
L2TPv3-2# sh l2tun tunn all
L2TP Tunnel Information Total tunnels 2 sessions 2
Tunnel id 3674041411 is up, remote id is 259422696, 1 active sessions
Remotely initiated tunnel
Tunnel state is established, time since change 1d22h
Tunnel transport is IP (115)
Remote tunnel name is L2TPv3-1
Internet Address 192.168.0.1, port 0
Local tunnel name is L2TPv3-2
Internet Address 192.168.0.5, port 0
L2TP class for tunnel is 555
Counters, taking last clear into account:
116312 packets sent, 77684 received
8282704 bytes sent, 5332116 received
Last clearing of counters never
Counters, ignoring last clear:
116312 packets sent, 77684 received
8282704 bytes sent, 5332116 received
Control Ns 16818, Nr 14
Local RWS 1024 (default), Remote RWS 1024
Control channel Congestion Control is disabled
Tunnel PMTU checking disabled
Retransmission time 1, max 1 seconds
Unsent queuesize 0, max 0
Resend queuesize 0, max 1
Total resends 0, ZLB ACKs sent 12
Total out-of-order dropped pkts 0
Total out-of-order reorder pkts 0
Total peer authentication failures 0
Current no session pak queue check 0 of 5
Retransmit time distribution: 0 0 0 0 0 0 0 0 0
Control message authentication is disabled
Tunnel id 3875190023 is up, remote id is 3905588394, 1 active sessions
Remotely initiated tunnel
Tunnel state is established, time since change 1d22h
Tunnel transport is IP (115)
Remote tunnel name is L2TPv3-1
Internet Address 192.168.0.2, port 0
Local tunnel name is L2TPv3-2
Internet Address 192.168.0.6, port 0
L2TP class for tunnel is 556
Counters, taking last clear into account:
113532 packets sent, 80129 received
8084174 bytes sent, 5498145 received
Last clearing of counters never
Counters, ignoring last clear:
113532 packets sent, 80129 received
8084174 bytes sent, 5498145 received
Control Ns 16820, Nr 15
Local RWS 1024 (default), Remote RWS 1024
Control channel Congestion Control is disabled
Tunnel PMTU checking disabled
Retransmission time 1, max 1 seconds
Unsent queuesize 0, max 0
Resend queuesize 0, max 3
Total resends 0, ZLB ACKs sent 12
Total out-of-order dropped pkts 0
Total out-of-order reorder pkts 0
Total peer authentication failures 0
Current no session pak queue check 0 of 5
Retransmit time distribution: 0 0 0 0 0 0 0 0 0
Control message authentication is disabled
L2TPv3-2#
L2TPv3-2# sh spanning-tree
No spanning tree instances exist.
3750-2# sh span mst
##### MST0 vlans mapped: 1-554,557-4094
Bridge address 000f.2325.a700 priority 0 (0 sysid 0)
Root this switch for the CIST
Operational hello time 2 , forward delay 15, max age 20, txholdcount 6
Configured hello time 2 , forward delay 15, max age 20, max hops 20
Interface Role Sts Cost Prio.Nbr Type
---------------- ---- --- --------- -------- --------------------------------
Fa1/0/13 Desg FWD 200000 128.15 P2p Bound(PVST)
Fa1/0/14 Desg FWD 200000 128.16 P2p
Fa1/0/15 Desg FWD 200000 128.17 P2p
Fa1/0/17 Desg FWD 200000 128.19 P2p
Fa1/0/21 Desg FWD 200000 128.23 P2p
##### MST1 vlans mapped: 555
Bridge address 000f.2325.a700 priority 4097 (4096 sysid 1)
Root this switch for MST1
Interface Role Sts Cost Prio.Nbr Type
---------------- ---- --- --------- -------- --------------------------------
Fa1/0/13 Desg FWD 200000 128.15 P2p Bound(PVST)
Fa1/0/14 Desg FWD 200000 128.16 P2p
##### MST2 vlans mapped: 556
Bridge address 000f.2325.a700 priority 8194 (8192 sysid 2)
Root this switch for MST2
Interface Role Sts Cost Prio.Nbr Type
---------------- ---- --- --------- -------- --------------------------------
Fa1/0/13 Desg FWD 200000 128.15 P2p Bound(PVST)
Fa1/0/15 Desg FWD 200000 128.17 P2p
