[c-nsp] MSTP between Cisco / Brocade

[Randy]

--- On Wed, 4/25/12, Steven Raymond <sraymond at acedatacenter.com> wrote:

> From: Steven Raymond <sraymond at acedatacenter.com>
> Subject: [c-nsp] MSTP between Cisco / Brocade
> To: "cisco-nsp Service Providers" <cisco-nsp at puck.nether.net>
> Date: Wednesday, April 25, 2012, 1:52 PM
> Have a single layer 2 connection
> between 7609, version 12.2(33)SRD4, 6708, with a 10G
> connection to Brocade.  Using simplest form of MSTP, it
> works "fine" to a Brocade TI24X switch, running version 4
> something.
> 
> Move the same cable to a 10G port on a MLXe, version
> 5.2.0T165, the Cisco blocks the port as the following:
> 
> ar01.prov#show spanning-tree active detail 
>  Port 4 (TenGigabitEthernet1/4) of MST0 is designated
> blocking (dispute)
>    Port path cost 2000, Port priority 128,
> Port Identifier 128.4.
>    Designated root has priority 16384,
> address 0015.62b7.0dc0
>    Designated bridge has priority 16384,
> address 0015.62b7.0dc0
>    Designated port id is 128.4, designated
> path cost 0
>    Timers: message age 0, forward delay 14,
> hold 0
>    Number of transitions to forwarding state:
> 0
>    Link type is point-to-point by default,
> Internal
>    BPDU: sent 20540, received 10287
> 
> Google suggests that this may be caused by both switches'
> ports declaring they are designated role for the segment,
> and the Cisco proceeds to block as a defense against
> uni-directional link.  But these same optics and cables
> work fine on the other device.  Even so, they have been
> swapped with same circumstance.  Am certain there is no
> uni-directional link here.
> 
> Other searching says that Cisco is bad and sends the BPDUs
> tagged and that native vlan tagging must be removed, which
> is not enabled to begin with.
> 
> Brocade said to add "pvst-mode" to the interface config on
> the MLXe side, but it did not help at all.  And I don't
> understand what PVST has to do with MSTP as currently
> configured.
> 
> Any suggestions?
> 
> Thanks!!


...I haven't played with Foundry/Brocade for a while.

It is clear that on the Cisco you have "enabled" 802.1s(MISTP)

I am not clear if you have 802.1s OR 802-1w enabled on the Brocade(care to post the stp output from Brocade?)

I ask because in the past Brocade/Foundry referred to 802.1W(R-PVST in Cisco-speak) as MULTIPLE-SPANNING-TREE!

./Randy