From: Timothy Snow (timsnow@cogeco.ca)
Date: Thu May 15 2003 - 03:42:43 GMT-3
> Nevermind, it appears my logic was messed up. Adjusted the vlan port-priorty
> on cat2-3550 (the root) to a lower number (high priority) and then port fa0/24
> went forwarding on the other cat. See below.
>
> change made on cat2-3550 (root) for vlan 14
>
> cat2-3550(config-if)#spanning-tree vlan 14 port-priority 1
> cat2-3550(config-if)#
>
> vlan 14 on cat1-3550 (before change on cat2)
>
> cat1-3550#sh span vlan 14
>
> VLAN0014
> Spanning tree enabled protocol ieee
> Root ID Priority 24590
> Address 0008.217a.4c80
> Cost 19
> Port 22 (FastEthernet0/22)
> Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
>
> Bridge ID Priority 28686 (priority 28672 sys-id-ext 14)
> Address 0009.e86c.8c80
> 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
> ---------------- -------- --------- --- --------- --------------------
> --------
> Fa0/22 128.22 19 FWD 0 24590 0008.217a.4c80 128.22
> Fa0/23 128.23 19 BLK 0 24590 0008.217a.4c80 128.23
> Fa0/24 128.24 19 BLK 0 24590 0008.217a.4c80 128.24
>
> -------------this is after change, notice fa0/24 is now forwarding
> -----------------
>
> cat1-3550#sh span vlan 14
>
> VLAN0014
> Spanning tree enabled protocol ieee
> Root ID Priority 24590
> Address 0008.217a.4c80
> Cost 19
> Port 24 (FastEthernet0/24)
> Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
>
> Bridge ID Priority 28686 (priority 28672 sys-id-ext 14)
> Address 0009.e86c.8c80
> Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
> Aging Time 15
>
> Interface Port ID Designated Port ID
>
> Name Prio.Nbr Cost Sts Cost Bridge ID
> Prio.Nbr
> ---------------- -------- --------- --- --------- --------------------
> --------
> Fa0/22 128.22 19 BLK 0 24590 0008.217a.4c80 128.22
> Fa0/23 128.23 19 BLK 0 24590 0008.217a.4c80 128.23
> Fa0/24 128.24 19 LIS 0 24590 0008.217a.4c80 1.24
>
> >
> > ------------------------------------------------------------------------
> >
> > Subject: cat3550's - Cost, Port Pri, vlan port pri. Help?
> > Date: Thu, 15 May 2003 01:15:15 -0400
> > From: Timothy Snow <timsnow@cogeco.ca>
> > To: ccielab@groupstudy.com, cfwong@acedsl.com, geoffz@mts.net
> >
> > Hey all..
> >
> > I'm working on the Hello computer lab #1
> >
> > cat1-3550 fa0/22 ----------- fa0/22 cat2-3550
> > fa0/23 ----------- fa0/23 cat2-3550
> > fa0/24 ----------- fa0/24 cat2-3550
> >
> > Right now, port fa0/22 is the port that cat1-3550 uses to get to the
> > root for vlan14, which is cat2-3550. (see below)
> >
> > at1-3550#sh span vlan 14
> >
> > VLAN0014
> > Spanning tree enabled protocol ieee
> > Root ID Priority 24590
> > Address 0008.217a.4c80
> > Cost 19
> > Port 22 (FastEthernet0/22)
> > Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
> >
> > Bridge ID Priority 28686 (priority 28672 sys-id-ext 14)
> > Address 0009.e86c.8c80
> > 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
> > ---------------- -------- --------- --- --------- --------------------
> > --------
> > Fa0/22 128.22 19 FWD 0 24590 0008.217a.4c80
> > 128.22
> > Fa0/23 128.23 19 BLK 0 24590 0008.217a.4c80
> > 128.23
> > Fa0/24 128.24 19 BLK 0 24590 0008.217a.4c80
> > 128.24
> >
> > After reading page 14-15 of the config guide, it says that regular port
> > priority "spanning-tree port-priority X" is used for access ports and
> > vlan port-priority "spanning-ree vlan Y port-priority X" is used for
> > trunk ports (which this is)
> >
> > As it stands, the priority is equal, the cost is equal, so it goes to
> > the lowest interface number (see FWD above)
> >
> > I tried to adjust using the vlan port-priority to the lowest number
> > (meaning highest priority) and the display shows it but fa0/24 doesn't
> > become FWD'ing like I expected. (see outout)
> >
> > cat1-3550(config-if)#spanning-tree vlan 14 port-priority 1
> > cat1-3550(config-if)#
> > cat1-3550#
> > May 15 02:07:52.059: %SYS-5-CONFIG_I: Configured from console by console
> >
> > cat1-3550#sh span vlan 14
> >
> > VLAN0014
> > Spanning tree enabled protocol ieee
> > Root ID Priority 24590
> > Address 0008.217a.4c80
> > Cost 19
> > Port 22 (FastEthernet0/22)
> > Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
> >
> > Bridge ID Priority 28686 (priority 28672 sys-id-ext 14)
> > Address 0009.e86c.8c80
> > 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
> > ---------------- -------- --------- --- --------- --------------------
> > --------
> > Fa0/22 128.22 19 FWD 0 24590 0008.217a.4c80
> > 128.22
> > Fa0/23 128.23 19 BLK 0 24590 0008.217a.4c80
> > 128.23
> > Fa0/24 1.24 19 BLK 0 24590 0008.217a.4c80
> > 128.24
> >
> > So it's a vlan port-pri is 1 (trunk port) as opposed to "regular
> > port-priority" but it hasn't becoming FWD'ing. So i'll go remove that
> > vlan port-pri, and changed the COST to something lower.
> >
> > cat1-3550(config-if)#spanning-tree vlan 14 cost 5
> > cat1-3550(config-if)#
> > May 15 02:10:04.695: %SYS-5-CONFIG_I: Configured from console by console
> >
> > cat1-3550#sh span vlan 14
> >
> > VLAN0014
> > Spanning tree enabled protocol ieee
> > Root ID Priority 24590
> > Address 0008.217a.4c80
> > Cost 5
> > Port 24 (FastEthernet0/24)
> > Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
> >
> > Bridge ID Priority 28686 (priority 28672 sys-id-ext 14)
> > Address 0009.e86c.8c80
> > Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
> > Aging Time 15
> >
> > Interface Port ID Designated
> > Port ID
> > Name Prio.Nbr Cost Sts Cost Bridge ID
> > Prio.Nbr
> > ---------------- -------- --------- --- --------- --------------------
> > --------
> > Fa0/22 128.22 19 BLK 0 24590 0008.217a.4c80
> > 128.22
> > Fa0/23 128.23 19 BLK 0 24590 0008.217a.4c80
> > 128.23
> > Fa0/24 128.24 5 FWD 0 24590 0008.217a.4c80
> > 128.24
> >
> > Am I doing something wrong here? I thought I had the understanding that
> > the selection goes as follows. COST, Port-pri, interface number
> > (tie-breaker) but it appears that no matter what I adjust the vlan
> > port-pri to it's never looked at even if cost was the same. I lower the
> > cost and the port I want to be FWD'ing is. What gives?
> >
> > Any help would be appreciated...
> >
> > Tim
This archive was generated by hypermail 2.1.4 : Mon Jun 02 2003 - 15:13:43 GMT-3