Re: STP access port start-up delay or intialization to

Ok, in the first example SW1 is connected to an access device:

SW1(config-if)#no shut
SW1(config-if)#
*Mar 1 00:23:53.947: STP: VLAN1 Fa1/1 -> listening
SW1(config-if)#
*Mar 1 00:23:54.787: %LINEPROTO-5-UPDOWN: Line protocol on Interface
FastEthernet1/9, changed state to up
SW1(config-if)#
*Mar 1 00:24:08.963: STP: VLAN1 Fa1/1 -> learning
SW1(config-if)#
*Mar 1 00:24:23.971: STP: VLAN1 Fa1/1 -> forwarding

The port moves immediately into listening state

The second exmple:
Port F1/2 on SW2 was root port and connected to SW1 F1/2
I shut down SW1 F1/2, but the root port an SW2 waits 20 seconds (max-age)
before Port F1/3 moves to listening state.

SW1(config-if)#shut
SW1(config-if)#
*Mar 1 00:26:29.093: STP: VLAN1 Fa1/2 -> blocking

SW2#
*Mar 1 00:26:49.181: STP: VLAN1 new root port Fa1/3, cost 19
*Mar 1 00:26:49.201: STP: VLAN1 Fa1/3 -> listening
SW2#
*Mar 1 00:27:04.209: STP: VLAN1 Fa1/3 -> learning
SW2#
*Mar 1 00:27:19.241: STP: VLAN1 sent Topology Change Notice on Fa1/3
*Mar 1 00:27:19.241: STP: VLAN1 Fa1/3 -> forwarding
SW2#

Hence, I conclude that we have to take the max-age time into consideration
when the task asks for inter-switch convergernce.
We do not have to take the max-age time into consideration to assure that an
access port gets to forwarding state wihthin a given timeframe.

Mike

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Received on Sat May 09 2009 - 23:31:37 ART