From: Scott Morris (swm@emanon.com)
Date: Wed Feb 14 2007 - 22:32:29 ART
More than you probably ever wanted to know.... :)
http://www.cisco.com/warp/public/473/122.html
Scott Morris, CCIE4 (R&S/ISP-Dial/Security/Service Provider) #4713, JNCIE
#153, CISSP, et al.
CCSI/JNCI-M/JNCI-J
IPexpert VP - Curriculum Development
IPexpert Sr. Technical Instructor
smorris@ipexpert.com
http://www.ipexpert.com
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Antonio Soares
Sent: Wednesday, February 14, 2007 8:19 PM
To: ccielab@groupstudy.com
Subject: STP Diameter
Dear GS,
Anybody knows which formula is used to set the STP timers based on the
diameter parameter ? The DocCD says:
"Use the diameter keyword to specify the Layer 2 network diameter (that is,
the maximum number of switch hops between any two end stations in the Layer
2 network). When you specify the network diameter, the switch automatically
sets an optimal hello time, forward-delay time, and maximum-age time for a
network of that diameter, which can significantly reduce the convergence
time. You can use the hello keyword to override the automatically calculated
hello time."
I don't see a pattern here:
Rack1SW2(config)#spanning-tree vlan 68 root primary diameter 2
Rack1SW2(config)#do sh span vlan 68 | inc Hello
Hello Time 2 sec Max Age 10 sec Forward Delay 7 sec
Hello Time 2 sec Max Age 10 sec Forward Delay 7 sec
Rack1SW2(config)#
Rack1SW2(config)#
Rack1SW2(config)#spanning-tree vlan 68 root primary diameter 3
Rack1SW2(config)#
Rack1SW2(config)#do sh span vlan 68 | inc Hello
Hello Time 2 sec Max Age 12 sec Forward Delay 9 sec
Hello Time 2 sec Max Age 12 sec Forward Delay 9 sec
Rack1SW2(config)#
Rack1SW2(config)#
Rack1SW2(config)#spanning-tree vlan 68 root primary diameter 4
Rack1SW2(config)#
Rack1SW2(config)#do sh span vlan 68 | inc Hello
Hello Time 2 sec Max Age 14 sec Forward Delay 10 sec
Hello Time 2 sec Max Age 14 sec Forward Delay 10 sec
Rack1SW2(config)#
Rack1SW2(config)#spanning-tree vlan 68 root primary diameter 5
Rack1SW2(config)#
Rack1SW2(config)#do sh span vlan 68 | inc Hello
Hello Time 2 sec Max Age 16 sec Forward Delay 12 sec
Hello Time 2 sec Max Age 16 sec Forward Delay 12 sec
Rack1SW2(config)#
Rack1SW2(config)#spanning-tree vlan 68 root primary diameter 6
Rack1SW2(config)#
Rack1SW2(config)#do sh span vlan 68 | inc Hello
Hello Time 2 sec Max Age 18 sec Forward Delay 13 sec
Hello Time 2 sec Max Age 18 sec Forward Delay 13 sec
Rack1SW2(config)#
Rack1SW2(config)#
Rack1SW2(config)#spanning-tree vlan 68 root primary diameter 7
Rack1SW2(config)#
Rack1SW2(config)#do sh span vlan 68 | inc Hello
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Rack1SW2(config)#
Thanks.
Antonio
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