RE: Spanning Tree on Doc CD

From: Derek Maffei (dmaffei@midwave.com)
Date: Wed Dec 03 2008 - 22:23:23 ARST


I completely agree that BKN may stand for BroKeN (root-inconsistent) ,
however I thought, and I may be incorrect, that a port in BKN state is
in blocking state. I too had an experience with this in real world
situation and debugging indicated that the port went to blocking state
as part of the BKN (inconsistency).

Aren't there still only 5 states (Blocking, Listening, Learning,
Forwarding and Disabled) of spanning tree?.

  

-----Original Message-----
From: Ronnie Angello [mailto:ronnie.angello@gmail.com]
Sent: Wednesday, December 03, 2008 2:35 PM
To: Derek Maffei
Cc: haider aly; L Pham; Amr; ccielab
Subject: Re: Spanning Tree on Doc CD

FYI if you want to lab this up - I just ran into this in the real
world. All you need is a simple 3 switch lab with the switches
connected in series. Switch C probably isn't really needed but is
what I was dealing with in this case.

A---B---C

Switch A is Cisco and runs MST. Switch B is Cisco and runs rapid
PVST+, and is configured to be the root for all VLANs. Switch C is HP
ProCurve and runs RSTP.

Observe the behavior on the MST boundary switch - switch A. There is
a really good explanation of the problem here.

http://blog.internetworkexpert.com/2008/09/24/mstp-tutorial-part-ii-outs
ide-a-region/

The section of particular interest is "Interoperating with PVST."

On Wed, Dec 3, 2008 at 3:23 PM, Ronnie Angello
<ronnie.angello@gmail.com> wrote:
> I meant BroKeN but you get the point...
>
> On Wed, Dec 3, 2008 at 3:22 PM, Ronnie Angello
<ronnie.angello@gmail.com> wrote:
>> Actually that means BRoKen - root inconsistent. Blocking would be
>> BLK. Remember what a designated port is - why would it be blocking?
>>
>> On Wed, Dec 3, 2008 at 2:24 PM, Derek Maffei <dmaffei@midwave.com>
wrote:
>>> BKN actually means blocking
>>>
>>> VLAN0123
>>> Spanning tree enabled protocol rstp
>>> Root ID Priority 32891
>>> Address 0050.3e05.9c00
>>> This bridge is the root
>>> Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
>>> Bridge ID Priority 32891 (priority 32768 sys-id-ext 123)
>>> Address 0050.3e05.9c00
>>> Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
>>> Aging Time 300
>>> Interface Role Sts Cost Prio.Nbr Type
>>> ---------------- ---- --- --------- --------
>>> --------------------------------
>>> Fa8/1 Desg BKN*19 240.897 P2p *ROOT_Inc
>>> Fa8/45 Desg FWD 19 128.941 P2p
>>> Gi9/14 Desg FWD 4 128.1038 P2p
>>> Gi9/15 Desg FWD 4 128.1039 Edge P2p
>>>
>>> ! "Desg" means designated port role; BKN means status blocking;
>>> ! FWD means forwarding. Notice the "ROOT Inc" status for port Fa8/1.
>>>
>>> -----Original Message-----
>>> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf
Of
>>> Ronnie Angello
>>> Sent: Wednesday, December 03, 2008 1:17 PM
>>> To: haider aly
>>> Cc: L Pham; Amr; ccielab
>>> Subject: Re: Spanning Tree on Doc CD
>>>
>>> Broken! The port is in a broken state for an inconsistency - root
>>> inconsistent, loopguard inconsistent, etc.
>>>
>>> On Wed, Dec 3, 2008 at 11:06 AM, haider aly <ccie.aly.110@gmail.com>
>>> wrote:
>>>> Hi Friends,
>>>> i just want to know.....what is this BKN state in STP...?
>>>>
>>>>
>>>> thanks & regards
>>>>
>>>> Haider Ali
>>>>
>>>>
>>>> On 12/3/08, L Pham <ccie17030@gmail.com> wrote:
>>>>>
>>>>> Amr, most ccie-wanabe should (at least ) know how to get here ...
>>>>>
>>>>> but, here it is:
>>>>> The Cisco Documentation pages have the same information that
>>>>> currently resides on UniversCD, please refer to the links on the
CCIE
>>>>> web pages to view these pages and become familiar with the new
>>> format.
>>>>>
>>>>> Cisco Documentation:
http://www.cisco.com/web/psa/products/index.html
>>>>>
>>>>> ->goto SWitching->your favorite-ios->pick a release -> look for
your
>>>>> answers!!!
>>>>>
>>>>> HTH,
>>>>> Loc
>>>>>
>>>>> On Wed, Dec 3, 2008 at 7:15 AM, Amr <amr.ccie@gmail.com> wrote:
>>>>> > Dear All
>>>>> > Where to find Spanning tree (PVST , MST , RSTP) on
the
>>> DOC CD
>>>>> ?
>>>>> >
>>>>> > Thanks In Advance
>>>>> >
>>>>> > Regards
>>>>> >
>>>>> >
>>>>> > Blogs and organic groups at http://www.ccie.net
>>>>> >
>>>>> >
>>>



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