[c-nsp] pvst+ & r-pvst (WAS Re: mst & pvst)

[Adam Greene]

OK, I made my way into the 6509, and it's not running MST as expected, but
PVST+. Duh ... the configs say "set spantree mode pvst+" so I should have
known.

Anyways.

So ...
    6509: PVST+
    3750: rapid-PVST

My impression is that the 3750 will fall back to 802.1D in this scenario, 
which means slower convergence, but otherwise things will work OK.

Any gotchas I should be aware of before I try this (besides checking the 
topology and adjusting priorities as needed)?

Thanks for your help,
Adam

----- Original Message ----- 
From: "Adam Greene" <maillist at webjogger.net>
To: "Mateusz Blaszczyk" <blahu77 at gmail.com>
Cc: <cisco-nsp at puck.nether.net>
Sent: Tuesday, March 25, 2008 4:32 PM
Subject: Re: [c-nsp] mst & pvst


> Thanks, Mat, this helps!
>
> ----- Original Message ----- 
> From: "Mateusz Blaszczyk" <blahu77 at gmail.com>
> To: "Adam Greene" <maillist at webjogger.net>
> Cc: <cisco-nsp at puck.nether.net>
> Sent: Tuesday, March 25, 2008 4:04 PM
> Subject: Re: [c-nsp] mst & pvst
>
>
>> On 25/03/2008, Adam Greene <maillist at webjogger.net> wrote:
>>> Hi,
>>>
>>>  I'm needing to set up a redundant trunk link between a 6509 and a 3750.
>>> The
>>>  6509 is running MST, the 3750 PVST. Am I going to have issues? I am
>>> assuming
>>>  so ...
>>>
>>>  Thanks,
>>>  Adam
>>>
>>>
>>>  ===
>>>  6509
>>>  ===
>>>
>>>  #MST (IEEE 802.1s)
>>>  set spantree fwddelay 15 mst
>>>  set spantree hello 2  mst
>>>  set spantree maxage 20 mst
>>>  set spantree mst maxhops 20
>>>  set spantree priority 0     mst 0-15
>>>  set spantree priority 32768 mst 16-4094
>>>
>>>  #MST Configuration
>>>  set spantree mst config rollback force
>>>  set spantree mst config name  revision 0
>>>  set spantree mst 0 vlan 1-4094
>>>  set spantree mst config commit
>>>
>>>  #vlan(defaults)
>>>  set spantree enable  1-16,30,40,99-100,123,128,192,840,888
>>>  set spantree fwddelay 15     1-16,30,40,99-100,123,128,192,840,888
>>>  set spantree hello    2      1-16,30,40,99-100,123,128,192,840,888
>>>  set spantree maxage   20     1-16,30,40,99-100,123,128,192,840,888
>>>  set spantree priority 32768  2-16,30,40,99-100,123,128,192,840,888
>>>
>>>  ====
>>>  3750
>>>  ====
>>>
>>>  spanning-tree mode rapid-pvst
>>>
>>>
>>
>> read here
>>
>> http://www.cisco.com/en/US/products/hw/switches/ps708/products_configuration_example09186a00807b075f.shtml#mst1
>> http://www.cisco.com/warp/public/473/147.html#invalid_configuration
>>
>> in a nutshell as long as mst priority for instance 0 (CST)  is better
>> then PVST, you are good to go, but also keep in mind not to disable
>> PVST on any VLANs on trunks between switches (no spt-disabled point to
>> point vlans). Also don't do asymetric vlan configurations on trunks -
>> remember that mst does not care about what vlans are actually
>> provisioned on links but how are the instances configured.
>>
>> The links should give you a good starting point
>>
>> Best Regards,
>>
>> -mat
>>
>>
>>
>>
>>
>
>
>
>
>
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