Re: Unicast flooding seen when using MST

The first thing that stands out from your output is that you have two
different MSTP regions.
Is this on purpose, and why?

Essentially, all of your MST instances are mapped to a single CIST between
regions. When you add the trunk, between two regions, you're causing a
topology change event that affects all of the MST instances!

-Yuri

On Sat, Dec 15, 2012 at 12:03 PM, Naufal Jamal <naufalccie_at_yahoo.in> wrote:

> Folks,
>
> We have an issue of unicast flooding in our network when we use MSTP.
> the topology is like this. Would like to see if anyone has seen similar
> issue
> in their networks
> When we add trunk link to the csw's or when we bounce the
> trunk we see the flooding also the MAC table doesn't flush. What things
> would
> you check in such a scenario? please share if you had any previous
> experiences..
>
> csw01---asw---csw02. asw is connected to both csw01 and csw02
> and MSTP is running between them.
>
> eat1-22164-csw02.corp# sh spanning-tree int
> eth2/9-----------> this link connects to t1/50 of asw
>
> Mst Instance Role
> Sts Cost Prio.Nbr Type
> ---------------- ---- --- --------- --------
> --------------------------------
> MST0000 Desg FWD 2000 128.265
> P2p
>
> MST0001 Desg FWD 2000 128.265 P2p
> eat1-22164-csw01.corp# sh spanning-tree int eth2/9------------> this link
> connects to t1/49 of asw
>
> Mst Instance Role Sts Cost Prio.Nbr Type
> ---------------- ---- --- --------- --------
> --------------------------------
> MST0000 Desg FWD 2000 128.265 P2p
>
> MST0001 Desg FWD
> 2000 128.265 P2p
>
> eat1-22164-asw324.corp#sh spanning-tree int t1/49
> Mst Instance Role Sts Cost Prio.Nbr Type
> ------------------- ----
> --- --------- -------- --------------------------------
> MST0
> Root FWD 2000 128.49 P2p Bound(RSTP)
> MST1 Mstr FWD
> 2000 128.49 P2p Bound(RSTP)
>
> eat1-22164-asw324.corp#sh spanning-tree
> int t1/50
>
> Mst Instance Role Sts Cost Prio.Nbr Type
> ------------------- ---- --- --------- --------
> --------------------------------
> MST0 Altn BLK 2000 128.50
> P2p Bound(RSTP)
> MST1 Altn BLK 2000 128.50 P2p
> Bound(RSTP)
>
>
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Received on Sat Dec 15 2012 - 12:50:12 ART