Hi
I have 3 location A, B, C
A has
stack cisco WS-C3750X-24
spanning-tree mode pvst
spanning-tree etherchannel guard misconfig
spanning-tree extend system-id
** I am looking into moving to MST
This is port-channeled to a stack of dell
8024f switches
spanning-tree mode mst
spanning-tree mst configuration
instance 1 add vlan 1
instance 2 add vlan 200-400
instance 3 add vlan 500-600
instance 5 add vlan 10,11,12,13
name "A"
revision 1
B has
2 x WS-C3560G-24PS no stack, but trunked ... (can't stack) each of these has a trunk to 8024F
spanning-tree mode mst
spanning-tree mst configuration
instance 1 vlan 1
instance 5 vlan 10,11,12,13
instance 7 vlan 80-90
instance 8 vlan 90-100
name "B"
revision 1
2x 8024f Dells
spanning-tree mode mst
spanning-tree mst configuration
instance 1 add vlan 1
instance 5 add vlan 10,11,12,13
instance 7 add vlan 80-90
instance 8 add vlan 90-100
name "B"
revision 1
C has
2x 8132f Dells
spanning-tree mode mst
spanning-tree mst configuration
instance 1 add vlan 1
instance 2 add vlan 200-400
instance 3 add vlan 500-600
instance 5 add vlan 10,11,12,13
name "C"
revision 1
I have 3 dark fibe cables to make a ring A -> B -> C -> A
I allow tagged vlans 10,11,12,13 on the dark fibre, running as a stretched vlan
so when i put this together B has a hiss fit. The cisco see PVST mis configure on the ports attached to the dell 8024F and block :( I believe the PVST bpdu packet from the cisco at site A are traversing via vlan 1, I haven't set the untagged vlan id on any of the ports so !!!! I will have to look at that.
I am going to try changing the PVID on the wan port on the 8024f to something apart from vlan1.
Now I have been reading the cisco documentation and it say vlan1 for IST is needed for MST region to MST Region communication, which is going to make it hard
So maybe instead of blocking vlan1 on the wan links just between the dell and the cisco's !
The document also says that vlan 1 needs to be in instance 0, but the documentation i had read on the dells say instance 1. it also says i need vlan 1 for IST stp ... so that why i need vlan 1 on the wan links.
I am thinking I might just take it out of any instance declaration and let it fall into instance 0.
Now what happens now with site to site traffic
for example
A -> C
vlan 10, its know in both MST regions (A & C) and i believe the inter MST region communication will have both regions saying they know about vlan 10 thats okay no loop. But then add in site B.
so site A will see that C has vlan 10 and site B has vlan 10, lets say it blocks site B port, can I unblock for certain vlans ? or cause its mst region to mst region its all or nothing.
All this inter region stuff is a pain, i could just go for 1 MST region and have lots of different MSTI, the thing that worries me about this is that I need the VLANS defined on all the switches, thus I am going to have vlans from site b configured in site A and C
Another bit of the puzzle with the 1 MST region is that the wan links only have some of the VLANS associated with them, if site C can't talk to the root bridge for vlan 30 what happens (at least not on vlan 30, cause its not allowed on the wan link)