From: Volkov, Dmitry (IDS Canada) (dmitry_volkov@ca.ml.com)
Date: Sat Aug 02 2003 - 13:59:29 GMT-3
It has effect on upstream (closest to root) switch
http://www.cisco.com/en/US/tech/tk389/tk621/technologies_tech_note09186a0080
0ae96a.shtml
> -----Original Message-----
> From: Jonathan V Hays [mailto:jhays@jtan.com]
> Sent: Saturday, August 02, 2003 12:42 PM
> To: 'John Matijevic'; ccielab@groupstudy.com
> Subject: RE: spanning-tree and port priority
>
>
> http://www.cisco.com/univercd/cc/td/doc/product/lan/c3550/1211
> 4ea1/3550s
> cg/swstp.htm#1020470
>
> quote:
> IF A LOOP OCCURS, spanning tree uses the port priority when
> selecting an
> interface to put into the forwarding state. You can assign higher
> priority values (lower numerical values) to interfaces that you want
> selected first and lower priority values (higher numerical
> values) that
> you want selected last. If all interfaces have the same
> priority value,
> spanning tree puts the interface with the lowest interface
> number in the
> forwarding state and blocks the other interfaces.
> end quote
>
> Note my emphasis on the phrase "if a loop occurs". My
> interpretation of
> the paragraph above is that the switch IOS ignores port
> priority until a
> loop occurs.
>
> HTH
>
>
> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On
> Behalf Of
> John Matijevic
> Sent: Saturday, August 02, 2003 12:14 PM
> To: John Matijevic; ccielab@groupstudy.com
> Subject: Re: spanning-tree and port priority
>
>
> 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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