From: kuldip singh (dipa.singh@gmail.com)
Date: Sat Oct 27 2007 - 15:41:17 ART
Hi Nicky,
I have just changed the forward delay timer (4 secs) for vlan 80
on the root bridge
and shut/unshut the root port on the neighbor switch , and you can see in
the log
messages below it take 8 seconds for the port to go from listening mode to
forwarding
state.Note forwarding delay timer = (listening + learning time).
02:47:58: STP: VLAN0080 Fa0/19 -> listening
02:48:00: STP: VLAN0080 new root port Fa0/19, cost 19
02:48:02: STP: VLAN0080 Fa0/19 -> learning
02:48:06: STP: VLAN0080 sent Topology Change Notice on Fa0/19
02:48:06: STP: VLAN0080 Fa0/19 -> forwarding
On 10/27/07, nicky noname <cisco2study@gmail.com> wrote:
>
> Hello,
>
> I have two conflicting methods of making a vlan converge asap.
>
> The first is:
> spanning-tree vlan 36 root primary diameter 3 hello-time 1
> { this will calculate a forward time of 5 and max age of 7......adding to
> a
> convergence time of 17 sec. But I think this may be the accepted answer? }
> {
> see output below}
>
>
> The second is:
> Rack8SW3(config)# spanning-tree vlan 36 forward-time 4
> Rack8SW3(config)# spanning-tree vlan 36 max-age 6
> { These commands will give a convergence time of 14 seconds.} {see output
> below}
>
> I would really appreciate an experienced opinion on this. ( in relation to
> the question)
>
> Thanks
> Nic
>
>
>
> ##############################################
> Rack8SW3(config)#spanning-tree vlan 36 root primary diameter 3 hello-time
> 1
>
> Rack8SW3(config)#do sh span vlan 36
>
> VLAN0036
> Spanning tree enabled protocol ieee
> Root ID Priority 24612
> Address 0009.e8e2.fc00
> This bridge is the root
> Hello Time 1 sec Max Age 7 sec Forward Delay 5 sec
>
> Bridge ID Priority 24612 (priority 24576 sys-id-ext 36)
> Address 0009.e8e2.fc00
> Hello Time 1 sec Max Age 7 sec Forward Delay 5 sec
> Aging Time 15
>
> Interface Role Sts Cost Prio.Nbr Type
> ---------------- ---- --- --------- --------
> --------------------------------
> Fa0/3 Desg FWD 19 128.3 P2p
> Fa0/16 Desg FWD 19 128.16 P2p
> Fa0/17 Desg FWD 19 128.17 P2p
> Fa0/18 Desg FWD 19 128.18 P2p
> Fa0/19 Desg FWD 19 128.19 P2p
> Fa0/20 Desg FWD 19 128.20 P2p
> Fa0/21 Desg FWD 19 128.21 P2p
> ###################################################
> Rack8SW3(config)# spanning-tree vlan 36 forward-time ?
> <4-30> number of seconds for the forward delay timer
>
> Rack8SW3(config)# spanning-tree vlan 36 forward-time 4
> Rack8SW3(config)# spanning-tree vlan 36 max
> Rack8SW3(config)# spanning-tree vlan 36 max-age ?
> <6-40> maximum number of seconds the information in a BPDU is valid
>
> Rack8SW3(config)# spanning-tree vlan 36 max-age 6
> Rack8SW3(config)#do sh span vlan 36
>
> VLAN0036
> Spanning tree enabled protocol ieee
> Root ID Priority 24612
> Address 0009.e8e2.fc00
> This bridge is the root
> Hello Time 2 sec Max Age 6 sec Forward Delay 4 sec
>
> Bridge ID Priority 24612 (priority 24576 sys-id-ext 36)
> Address 0009.e8e2.fc00
> Hello Time 2 sec Max Age 6 sec Forward Delay 4 sec
> Aging Time 15
>
> Interface Role Sts Cost Prio.Nbr Type
> ---------------- ---- --- --------- --------
> --------------------------------
> Fa0/3 Desg FWD 19 128.3 P2p
> Fa0/16 Desg FWD 19 128.16 P2p
> Fa0/17 Desg FWD 19 128.17 P2p
> Fa0/18 Desg FWD 19 128.18 P2p
> Fa0/19 Desg FWD 19 128.19 P2p
> Fa0/20 Desg FWD 19 128.20 P2p
> Fa0/21 Desg FWD 19 128.21 P2p
> #########################################################
>
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