RE: UPLINKFAST versus BACKBONEFAST

From: Dennis J. Hartmann (dhartma5@optonline.net)
Date: Tue Apr 26 2005 - 22:26:21 GMT-3


        When you configure uplinkfast on an ACCESS layer switch, the switch
modifies it's Bridge Priority to 49,152 + VLAN to ensure that the switch is
NEVER the root bridge because the default bridge priority is 32,768
(0x8000). Remember that LOWER is better with Root Bridge selection in IEEE
802.1d STP.

S5#show spanning-tree

VLAN0001
  Spanning tree enabled protocol ieee
  Root ID Priority 32768
             Address 0001.42ce.fbc0
             Cost 3038
             Port 23 (FastEthernet0/23)
             Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec

  Bridge ID Priority 49153 (priority 49152 sys-id-ext 1)
             Address 000c.301f.a400
             Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
             Aging Time 300
  Uplinkfast enabled

Interface Port ID Designated Port
ID
Name Prio.Nbr Cost Sts Cost Bridge ID
Prio.Nbr
---------------- -------- --------- --- --------- --------------------
--------
Fa0/8 128.8 3100 FWD 3038 49153 000c.301f.a400 128.8
Fa0/23 128.23 3019 FWD 19 32768 0030.94d0.cc00
128.24
Fa0/24 128.24 3019 FWD 3038 49153 000c.301f.a400
128.24

-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Brant I. Stevens
Sent: Wednesday, April 20, 2005 4:42 PM
To: 'PhiL'; 'Group Study (E-mail)'; 'PhiL'; 'Group Study (E-mail)'
Subject: RE: UPLINKFAST versus BACKBONEFAST

Yes... You don't "need" it, but backbonefast should be enabled on all
switches in an L2 domain. Backbonefast protects against indirect link
failures. Uplinkfast should be enabled on all your edge switches; not the
root and "backup" roots.

-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of PhiL
Sent: Wednesday, April 20, 2005 2:07 PM
To: Group Study (E-mail); theccie@gmail.com
Subject: OT: UPLINKFAST versus BACKBONEFAST

All,

I was reading about uplinkfast and backbonefast on CatOS. If I have
uplinkfast enabled on all my switches, would I ever need backbonefast
enabled also?

--
Regards,

PhiL



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