From: Sean C (Upp_and_Upp@hotmail.com)
Date: Mon May 02 2005 - 18:05:54 GMT-3
Hi Gladston,
Ok, I'll bite. Let me ask this (and I don't have the luxury of a 3550 to
test). What is the STP state of the interface when the port is shutdown?
Is the port in a blocking state or is it in a down state? I do have access
to a 2950, when a port is shut, span tree is down, not blocked. Not sure if
the same for a 3550.
Since max-age is the time to wait before forcing a recalculation of the
spanning-tree, doesn't the port first need to be in a blocking state to
utilize max-age, not a down state?
Cat2900(config)#int f0/5
Cat2900(config-if)#shut
Cat2900(config-if)#end
Cat2900#sho spanning-tree interface f0/5
Interface Fa0/5 (port 17) in Spanning tree 1 is DOWN
Cat2900#config t
Cat2900(config)#int f0/5
Cat2900(config-if)#no shut
Cat2900(config-if)#end
Cat2900#sho spanning-tree interface f0/5
Interface Fa0/5 (port 17) in Spanning tree 1 is LISTENING
Can you configure your topology to put a port in a blocking state (I can't)?
Perhaps the question that needs to be answered is what state is the port
transitioning from - blocking state or shutdown state.
Sean
----- Original Message -----
From: <gladston@br.ibm.com>
To: <ccielab@groupstudy.com>
Sent: Monday, May 02, 2005 2:35 PM
Subject: Forward Delay
> Hi,
>
> The quoted discussion was about setting the time for a port go to forward
> state.
>
> Considering the CCIE lab is not about Best Practices, why should we set
> the maxage time? (if the task ask us to adjust the STP timers so a port
> take 16 seconds to go to forward state)
>
> The test that follows shows there is no difference on the time the port
> takes to go to forward state changing MAXAGE. (the task considers access
> port)
>
> ===============
> quoted
>
> Hello,
>
> you have to change the forward and maxage timers. STP by default uses a
> maxage timer of 20 seconds and a forward timer of 15 second (x2 =30). To
> achieve 16 seconds, you have to configure:
>
> spanning-tree vlan x forward-time 5 max-age 6
>
> Regards,
>
> GP
> ================
>
>
> CAT2(config)#int fa 0/1
> CAT2(config-if)#sh
> CAT2(config)#int fa 0/1
> CAT2(config-if)#do sh clock
> 03:22:25.555 UTC Mon May 2 2005
> CAT2(config-if)#no sh
> CAT2(config-if)#^Z
> CAT2#sh spanning-tree int fa 0/1
>
> Vlan Role Sts Cost Prio.Nbr Type
> ---------------- ---- --- --------- -------- --------------------------------
> VLAN0034 Desg LIS 19 128.1 P2p
> CAT2#sh spanning-tree int fa 0/1
>
> Vlan Role Sts Cost Prio.Nbr Type
> ---------------- ---- --- --------- -------- --------------------------------
> VLAN0034 Desg LIS 19 128.1 P2p
> CAT2#sh spanning-tree int fa 0/1
>
> Vlan Role Sts Cost Prio.Nbr Type
> ---------------- ---- --- --------- -------- --------------------------------
> VLAN0034 Desg LRN 19 128.1 P2p
> CAT2#sh spanning-tree int fa 0/1
>
> Vlan Role Sts Cost Prio.Nbr Type
> ---------------- ---- --- --------- -------- --------------------------------
> VLAN0034 Desg LRN 19 128.1 P2p
> CAT2#sh spanning-tree int fa 0/1
>
> Vlan Role Sts Cost Prio.Nbr Type
> ---------------- ---- --- --------- -------- --------------------------------
> VLAN0034 Desg FWD 19 128.1 P2p
> CAT2#sh clock
> 03:22:40.467 UTC Mon May 2 2005
>
> CAT2#sh spanning-tree vlan 34
>
> VLAN0034
> Spanning tree enabled protocol ieee
> Root ID Priority 32802
> Address 000c.cebd.8000
> This bridge is the root
> Hello Time 2 sec Max Age 20 sec Forward Delay 4 sec
>
> Bridge ID Priority 32802 (priority 32768 sys-id-ext 34)
> Address 000c.cebd.8000
> Hello Time 2 sec Max Age 20 sec Forward Delay 4 sec
> Aging Time 300
>
> Interface Role Sts Cost Prio.Nbr Type
> ---------------- ---- --- --------- -------- --------------------------------
> Fa0/1 Desg FWD 19 128.1 P2p
> Fa0/2 Desg FWD 19 128.2 Edge P2p
> Fa0/47 Desg FWD 19 128.47 P2p
> Fa0/48 Desg FWD 19 128.48 P2p
> Gi0/1 Desg FWD 4 128.49 P2p
> Gi0/2 Desg FWD 4 128.50 P2p
>
>
> CAT2(config)#spanning-tree vlan 34 max-age 6
> CAT2(config)#
> CAT2(config)#int fa 0/1
> CAT2(config-if)#do sh clock
> 03:23:46.007 UTC Mon May 2 2005
> CAT2(config-if)#no sh
> CAT2(config-if)#^Z
> CAT2#sh spanning-tree int fa 0/1
>
> Vlan Role Sts Cost Prio.Nbr Type
> ---------------- ---- --- --------- -------- --------------------------------
> VLAN0034 Desg LRN 19 128.1 P2p
> CAT2#sh spanning-tree int fa 0/1
>
> Vlan Role Sts Cost Prio.Nbr Type
> ---------------- ---- --- --------- -------- --------------------------------
> VLAN0034 Desg LRN 19 128.1 P2p
> CAT2#sh spanning-tree int fa 0/1
>
> Vlan Role Sts Cost Prio.Nbr Type
> ---------------- ---- --- --------- -------- --------------------------------
> VLAN0034 Desg FWD 19 128.1 P2p
> CAT2#sh clock
> 03:23:59.939 UTC Mon May 2 2005
> CAT2#sh spanning-tree vlan 34
>
> VLAN0034
> Spanning tree enabled protocol ieee
> Root ID Priority 32802
> Address 000c.cebd.8000
> This bridge is the root
> Hello Time 2 sec Max Age 6 sec Forward Delay 4 sec
>
> Bridge ID Priority 32802 (priority 32768 sys-id-ext 34)
> Address 000c.cebd.8000
> Hello Time 2 sec Max Age 6 sec Forward Delay 4 sec
> Aging Time 300
>
> Interface Role Sts Cost Prio.Nbr Type
> ---------------- ---- --- --------- -------- --------------------------------
> Fa0/1 Desg FWD 19 128.1 P2p
> Fa0/2 Desg FWD 19 128.2 Edge P2p
> Fa0/47 Desg FWD 19 128.47 P2p
> Fa0/48 Desg FWD 19 128.48 P2p
> Gi0/1 Desg FWD 4 128.49 P2p
> Gi0/2 Desg FWD 4 128.50 P2p
>
>
>
> CAT2(config)#spanning-tree vlan 34 max-age 40
> CAT2(config)#int fa 0/1
> CAT2(config-if)#do sh clock
> 03:24:57.419 UTC Mon May 2 2005
> CAT2(config-if)#no sh
> CAT2(config-if)#^Z
> CAT2#sh spanning-tree int fa 0/1
>
> Vlan Role Sts Cost Prio.Nbr Type
> ---------------- ---- --- --------- -------- --------------------------------
> VLAN0034 Desg LIS 19 128.1 P2p
> CAT2#sh spanning-tree int fa 0/1
>
> Vlan Role Sts Cost Prio.Nbr Type
> ---------------- ---- --- --------- -------- --------------------------------
> VLAN0034 Desg LRN 19 128.1 P2p
> CAT2#sh spanning-tree int fa 0/1
>
> Vlan Role Sts Cost Prio.Nbr Type
> ---------------- ---- --- --------- -------- --------------------------------
> VLAN0034 Desg LRN 19 128.1 P2p
> CAT2#sh spanning-tree int fa 0/1
>
> Vlan Role Sts Cost Prio.Nbr Type
> ---------------- ---- --- --------- -------- --------------------------------
> VLAN0034 Desg LRN 19 128.1 P2p
> CAT2#sh spanning-tree int fa 0/1
>
> Vlan Role Sts Cost Prio.Nbr Type
> ---------------- ---- --- --------- -------- --------------------------------
> VLAN0034 Desg FWD 19 128.1 P2p
> CAT2#sh clock
> 03:25:13.483 UTC Mon May 2 2005
>
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