From: yu chunyan (yuchunyan@hotmail.com)
Date: Sat Aug 02 2003 - 22:50:04 GMT-3
Hi,
I donot know if you have book "cisco lan switching' written by kennedy
clark, which talk about every thing about spanning tree problem. This is a
common mistake one ever makes about spanning tree. If you want port-priority
to affect the root port selection, you have to set port-priority in upstream
switch, not the switch you want to change, and this technique is only proper
in back to back case. If you have mutiple upstream switch, it does not work.
read the book.
Bin.
>From: "John Matijevic" <matijevi@bellsouth.net>
>Reply-To: "John Matijevic" <matijevi@bellsouth.net>
>To: "John Matijevic" <matijevi@bellsouth.net>, <ccielab@groupstudy.com>
>Subject: Re: spanning-tree and port priority
>Date: Sat, 2 Aug 2003 12:14:00 -0400
>
>Team,
>If anyone can get this to work using port-priority command please let me
>know. Otherwise I am assuming the DocCd is wrong that the port-priority
>value modification does not make a difference.
>The only way I could change the state from forwarding to blocking was to
>adjust the cost. In my initial thinking based on the DocCd I thought I
>could
>do this with the port-priority. I even tried using the value 112. Based on
>the following:
>Valid priority values are 0, 16, 32, 48, 64, 80, 96, 112, 128, 144, 160,
>176, 192, 208, 224, and 240. All other values are rejected.
>
>Sincerely,
>
>Matijevic
>
>----- Original Message -----
>From: "John Matijevic" <matijevi@bellsouth.net>
>To: <ccielab@groupstudy.com>
>Sent: Saturday, August 02, 2003 11:29 AM
>Subject: spanning-tree and port priority
>
>
> > Hello Team,
> > I know there is an ealier thread on 7/7/03, on this that I read, but no
> > response.
> > I am trying to change the state from blocking to forwarding on a
>non-root
> > switch.
> > I used the command under interface:
> > spanning-tree vlan 1 port-priority 100,
> > By lowering the priority the port should go into forwarding state and
>the
>rest
> > should be blocking. However, this is not happening, I know there was an
> > earlier thread on this but there was no response.
> > p1s2#sh span vlan 1
> >
> > VLAN0001
> > Spanning tree enabled protocol ieee
> > Root ID Priority 24577
> > Address 000b.be5d.5b80
> > Cost 19
> > Port 21 (FastEthernet0/21)
> > Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
> >
> > Bridge ID Priority 32769 (priority 32768 sys-id-ext 1)
> > Address 000b.46d9.2580
> > Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
> > Aging Time 300
> >
> > Interface Port ID Designated
>Port
> > ID
> > Name Prio.Nbr Cost Sts Cost Bridge ID
> > Prio.Nbr
> > ---------------- -------- --------- --- --------- --------------------
> > --------
> > Fa0/21 128.21 19 FWD 0 24577 000b.be5d.5b80
>128.21
> > Fa0/22 128.22 19 BLK 0 24577 000b.be5d.5b80
>128.22
> > Fa0/23 128.23 19 BLK 0 24577 000b.be5d.5b80
>128.23
> > Fa0/24 100.24 19 BLK 0 24577 000b.be5d.5b80
>128.24
> >
> > p1s2#
> > port fa0/21 is the port im trying to change, on the non-root switch.
> > Any suggestions?
> > Sincerely,
> > Matijevic
> >
> >
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