CCIE Pursuit Blog

January 1, 2008

Internetwork Expert Volume III: Lab 3 – Section 2

2 Bridging and Switching

2.1 VLAN Assignments

This should have been a very simple task, but a couple of interesting wrinkles made this a harder task than normal.  I was going to blog my whole “stream of thought” experience, but you’ll get enough of that in section 4, so I’ll spare you.  🙂

Usually you are given a list of VLANs and interfaces to configure, but in this case you are asked to configure VLANs and interfaces from the network diagram only.  This is a really good exercise.  The biggest twist with this lab (and the part that took me the most amount of time) is that you will not have VTP to propagate the VLANs to the appropriate switches (more on that in a bit) so you will need to make sure that you take trunking into account when assigning VLANs to each switch.

The reason you cannot use VTP is because one of the VLANs you need to configure is VLAN 2569.  This in an extended VLAN so VTP will not allow you to configure it:

sw1(config)#vtp mode server
sw1(config)#vtp domain IE
Changing VTP domain name from NULL to IE
sw1(config)#vlan 2569
% Failed to create VLANs 2569
Extended VLAN(s) not allowed in current VTP mode.
%Failed to commit extended VLAN(s) changes.

In this case VLAN 2569 is going to need to be present on each switch.  We are also tasked with running VTP so we’ll need to configure all of the switches as VTP Transparent.  This means that your VLANs are not going to propagate from switch to switch.  The easy way to handle this is to assign all known VLANs on each switch.  The IE solution does not show this.  This may be a limitation of this subtask:

“Configure VLAN assignments per the diagram.”

In the real lab you should ask the proctor about this.  It’s also good to know that you can configure all known VLANs on each switch as a workaround if you are short on time.

One other caveat for this task: you will not be able to verify reachability for some addresses until you get your trunking built (covered in the next two tasks).

2.2 Trunking

This is a very easy trunking task.  The only bit of oddness is that the IE solution guide has “switchport nonegotiate” for all trunking interfaces. I don’t see anything in the task that requires that DTP be disabled.  

2.3 EtherChannel

Easy enough.  A layer 2 map comes in handy as you are only given the interfaces on one side of each etherchannel. 

IE solution is wrong for subtask 2.  It shows “channel-group 1 mode active” when it should be “channel-group 2 mode active”.


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