RE: Root Bridge

With OLDER IOS and OLDER switches (usually 3750's and smaller) if you create
the SVI it does NOT automatically create the vlan in the layer 2 vlan
database.

I have HEARD some newer models do, but I haven't tested them yet.

So,

Plan and build your layer 2 topology starting with creating the vlan's on each
switch or using VTP and working trunks to propagate vlan databases to your
switches.

If you have to create lots of vlans you can just make 1 switch a server,
config the trunk ports and add the vlans to the vtp server. When done, you can
make the client switches transparent (the vlan database as it's last heard is
maintained. This gives you a speed advantage in manually creating and checking
many vlans.

-Joe

From: Tony claros [mailto:tonyclaros26_at_gmail.com]
Sent: Monday, April 11, 2011 6:00 PM
To: Joseph L. Brunner
Cc: Cisco certification
Subject: Re: Root Bridge

Hey Joe

Vlan 3 is only L2. no SVI created.
This suprised me...

On Tue, Apr 12, 2011 at 12:50 AM, Joseph L. Brunner
<joe_at_affirmedsystems.com<mailto:joe_at_affirmedsystems.com>> wrote:
This forum is for CCIE Lab candidates who have already passed written exam.

I seriously suggest you go back and review the theory of spanning-tree a
little more. The fact you are unsure of this reveals key gaps in your
knowledge that will cause you to have issues on the lab.

In short to answer your question, Was Vlan 3 created in SWA's database?

SWA#Show vlan

-Joe

-----Original Message-----
From: nobody_at_groupstudy.com<mailto:nobody_at_groupstudy.com>
[mailto:nobody_at_groupstudy.com<mailto:nobody_at_groupstudy.com>] On Behalf Of Tony
claros
Sent: Monday, April 11, 2011 5:32 PM
To: Cisco certification
Subject: Root Bridge

Hi

Switch A being Server and got Spanning-tree priority 0 Switch B is client
There is dot1q trunk between Switch A and Switch B

Why do switch B indicates Root bridge for: VLAN0003

SWA# sh spanning-tree sum
Switch is in pvst mode
Root bridge for: VLAN0009, VLAN0010, VLAN0020, VLAN0030, VLAN0040-VLAN0041
Extended system ID is enabled
Portfast Default is enabled
PortFast BPDU Guard Default is disabled Portfast BPDU Filter Default is
enabled
Loopguard Default is disabled
EtherChannel misconfig guard is enabled
UplinkFast is disabled
BackboneFast is disabled
Configured Pathcost method used is short
Name Blocking Listening Learning Forwarding STP Active
---------------------- -------- --------- -------- ---------- ----------
VLAN0009 0 0 0 6 6
VLAN0010 0 0 0 6 6
VLAN0020 0 0 0 6 6
VLAN0030 0 0 0 1 1
VLAN0040 0 0 0 6 6
VLAN0041 0 0 0 6 6
---------------------- -------- --------- -------- ---------- ----------
6 vlans 0 0 0 31 31

*********************************************************

SWB# sh spanning-tree sum
Switch is in pvst mode
Root bridge for: VLAN0003
Extended system ID is enabled
Portfast Default is enabled
PortFast BPDU Guard Default is disabled Portfast BPDU Filter Default is
enabled
Loopguard Default is disabled
EtherChannel misconfig guard is enabled
UplinkFast is disabled
BackboneFast is disabled
Configured Pathcost method used is short
Name Blocking Listening Learning Forwarding STP Active
---------------------- -------- --------- -------- ---------- ----------
VLAN0003 1 0 0 0 1
VLAN0009 1 0 0 5 6
VLAN0010 1 0 0 5 6
VLAN0020 1 0 0 5 6
VLAN0030 1 0 0 5 6
VLAN0040 1 0 0 5 6
---------------------- -------- --------- -------- ---------- ----------
6 vlans 6 0 0 25 31

**********************************************

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Received on Mon Apr 11 2011 - 22:07:37 ART