Cisco Support Community
cancel
Showing results for 
Search instead for 
Did you mean: 
Announcements
Webcast-Catalyst9k
New Member

two MST regions

Hello,

1) If two different MST regions with instances MST0 MST1 and MST2 are interconnected, root bridge for MST1 and MST2 should be inside corresponding region. Shall root for MST 0 instance be only in one region on bridge with lowest priority?

I know that when PVST+ is connected to MST, if MST switch receives BPDU that claims that root is in PVST+,ROOTGUARD automaticly blocks this port.

What happens beetwen two MST regeions?

2) Further more if one region has IEEE MST and other has pre-standard MST should there be a problem if IEEE MST switch toward pre-stanbdard switch doesn't have configured interface as "spanning-tree mst pre-standard" ?

Because I have situation where "show spanning-tree mst interface detail" on IEEE MST swith shows :

Boundary : internal pre-standard (rcvd)

and on the other side of the link on pre-stanndard MST shows :

Boundary : boundary

It seems that IEEE MST regionn considers pre-standard MST region as internal, but pre-standard MST considers interface toward IEEE MST as boundary (as it should be)

thanks in advance,

A

1 REPLY
Hall of Fame Super Silver

Re: two MST regions

Hello Antonio,

you have probably solved this.

anyway

1) yes the two different regions should interact on CST

2) I've found this description of what should happen in interaction between MST 802.1s and prestandard

http://www.cisco.com/en/US/docs/switches/lan/catalyst6500/ios/12.2SX/configuration/guide/spantree.html#wp1098743

and behaviour should be different

Hope to help

Giuseppe

929
Views
0
Helpful
1
Replies
CreatePlease to create content