VLSM + STP

wizarddeath

Well having failed the exam, I know my weak areas. I saw what was wrong on one sim, but could not for the life of me figure out what the command was to fix it....Sucked!

After getting to the second sim, and blowing it, I then realized I had no chance of passing(from what I heard the sims are the make or breaker no matter how well you do on the rest of the exam). I half heartley answered a few questions without getting into any serious math. =/

Took a day off, and Im ready to study and beat this thing when I go back next week!


Score was 675 btw if you wondering, dont look down on me to much =/
Now on to the questions.....

I only have 1 switch, my Sybex book only shows the spanning tree protocol screen running with 1 switch, Id like to see what the show spanning-tree command looks like with multiple switches configured in a VLAN. Having trouble dealing with the root bridge. I know its the lowest priority, then its the lowest mac address, but it only displays the root priority, where in the command does it show you the name of the root switch? Or do you have to telnet around to the switches and check their priority and then determine based on that who is the root?

Also, looking for some more VLSM models and explanation with practice questions if anyone has any good sites. I can seem to figure out most of the questions based on the answers, but Id rather be able to actually solve the problem without having to look at the answers and cross out the wrong ones to pick the right ones.

Thanks

kplab

The "show spanning-tree" command can display the MAC address of the root bridge.

Here are some sites with free practice questions:

www.learntosubnet.com
www.celticrover.com
www.techexams.net
www.free-tests.com

xanderuk2

Perhaps with the Spanning-tree root bridge question you can determine the Root Bridge with the Show-spanning-tree command to get the Mac address, then do a show cdp neighbor to see if the MAC address of any directly connected switches are the same?

As far as I am aware, it only displays the message "this bridge is the root" if you are on the Switch that is in fact the root bridge.....frustrating I know.
I've been doing research into this and am still rather fuzzy on the whole "find the root bridge in this switch network".....
It's all very well finding the MAC address, but it's the root-bridge hostname thats needed

EdTheLad

Just to let you know, when implementing a network positioning of the root bridge should be well planned along with a backup root bridge, so its highly unlikely that when administrating a switched network you will be looking for the root bridge.Also im sure most admins keep a list of switch MAC addresses so knowing the MAC address should suffice.

wizarddeath

xanderuk2 wrote:

Perhaps with the Spanning-tree root bridge question you can determine the Root Bridge with the Show-spanning-tree command to get the Mac address, then do a show cdp neighbor to see if the MAC address of any directly connected switches are the same?

As far as I am aware, it only displays the message "this bridge is the root" if you are on the Switch that is in fact the root bridge.....frustrating I know.
I've been doing research into this and am still rather fuzzy on the whole "find the root bridge in this switch network".....
It's all very well finding the MAC address, but it's the root-bridge hostname thats needed

Sounds like that would work Xander, Im a bit hazy also. Without trying to go into to much detail. If your a new network admin, and had no paperwork, basically how would you go about finding the root switch? I know show spanning tree, but how do i tell which switch that mac address belongs to?

Humper

Spanning tree 1 is executing the IEEE compatible Spanning Tree protocol
  Bridge Identifier has priority 32768, address 0003.e355.eb40
  Configured hello time 2, max age 20, forward delay 15

  We are the root of the spanning tree


  Topology change flag set, detected flag set, changes 3
  Times:  hold 1, topology change 35, notification 2
          hello 2, max age 20, forward delay 15
  Timers: hello 1, topology change 6, notification 0

The other 2900 switch I have with trunk link between the two:

Spanning tree 1 is executing the IEEE compatible Spanning Tree protocol
  Bridge Identifier has priority 65535, address 0004.2707.8e80
  Configured hello time 2, max age 20, forward delay 15


  Current root has priority 32768, address 0003.e355.eb40
  

  Root port is 24, cost of root path is 1
  Topology change flag not set, detected flag not set, changes 2
  Times:  hold 1, topology change 35, notification 2
          hello 2, max age 20, forward delay 15
  Timers: hello 0, topology change 0, notification 0

EdTheLad

wizarddeath wrote:

If your a new network admin, and had no paperwork, basically how would you go about finding the root switch?

Follow the root port back to the root bridge.