Prioritisation of Spanning-tree MST

Good Afternoon, (or good morning depending where you are)

I'm wondering if someone could shed some light of a QoS concern I've got. I'm
trying to work out the best method for prioritising network control traffic.
Mostly I guess this is pretty easy, OSPF/LDP/BGP/ISIS etc all gets marked as
DSCP46 and CoS 7 (if tagged) by default so all I should need to do is create a
class that matches all this traffic. A'la;

Class-map match-any network-control
  Match dscp cs6
  Match cos 7

Spanning-tree on the other hand though seems to be a little trickier to me.
If you use MST (which I am) then BPDUs are not sent with dot1q tags and so I
can't match the cos value. I could match the destination mac address
01:80:c2:00:00:00 but due to hardware limitations (ME3600X) I'm not able to do
that on an outbound policy map. I have exactly the same issue for other
native VLAN protocols such as UDLD (dest mac 01:00:0C:CC:CC:CC ethertype
0x0111). Oddly, even with the 'vlan dot1q tag native' command issued, these
control messages still appear to be sent untagged.

Does anyone have any ideas about this and/or is there I reason that I
shouldn't even be concerned. I haven't been able to find anything that
addresses my concerns really. I'm nervous that the building blocks of a
network are going to end up in the class-default, or is that not the case?

Many thanks in advance

Alex
Received on Fri Jul 06 2012 - 15:01:17 ART