08-26-2013 01:46 AM
Hello,
I have a problem integrating 2 x ASR9000 with 2 x 7600
The topology is Just simple
A9k--------A9K
| |
7600------7600
ASR 9000 is running MST , while 7600 is running PVST all attached using a Single Tengig Interface.
The problem I have that i can see there are two roots - A root per each Protocol Rootbridge for MST and root for PVST
Is there a specific best practice for integration in such, I need to run it using spanning tree , as PVSTAG will not be included in spanning tree Algorithm , and i was not able to connect a server dual homed to the two 9ks.
Thanks!
08-26-2013 06:09 AM
Rando,
The mixing of STPs can get tricky. Now depending on your MST config you could see a root for MST CIST and then different roots for the PVST vlans that are not included in the CIST.
Here is a decent doc on MST and integrating it with PVST.
http://www.cisco.com/en/US/tech/tk389/tk621/technologies_white_paper09186a0080094cfc.shtml
Simply put, we should see all roots in MST region or just CIST in MST and ALL other vlans not included in CIST need to be seen as a root in MST or PVST. Can't be mixed.
If you want to include snippets of your MST and PVST configs we can look at it further.
Thanks,
Bryan
08-26-2013 09:04 AM
On both ASR9K:
spanning-tree mst Trust_sig
name Trust_sig
revision 1
instance 0
priority 32786
!
instance 1
vlan-ids 100,200
priority 32786
!
interface GigabitEthernet0/0/0/2
!
interface GigabitEthernet0/1/0/2
!
l2vpn
bridge group Trust_sig
bridge-domain Trust_sig1
interface GigabitEthernet0/0/0/2
interface GigabitEthernet0/1/0/2
On 7600 its normal PVST configuration with priority 0 on 7600(1)
Is there any specific thing i need to do from PVST side or from MST side? also now i am having a spanning tree loops.
I need to insure interoperability between both sides , and also that 7600(1) always act as the root for vlan 100 and vlan 200
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