Kevin Dorrell, CCIE #20765

09 Mar 2008

NMC Lab 11

Filed under: General — dorreke @ 22:22

2008 week 11, Lab 11.  This is the second time I have tackled this lab; the first time was in 2007 week 43.  But since it fits in the cycle I decided to do it anyway.  In any case, I was interested to see how much I had retained from 20 weeks ago.  I am pleased to say I retained quite a lot, and managed to “complete” in exactly four hours … all except the two corner cases of 11.12 (Router Management) and 11.13 (Multicast).

I was also pleased that the redistribution worked first time.  I think I planned it rather better than usual as I was already familiar with the topology.  In the AK, there is a challenge about “Can you come up with a scheme that could handle additional failed links?”  Well, I think this lab makes an excellent test-bed for redistribution ideas.  I am glad I got it finished so quickly because I intend to spend most of the rest of the week playing with the redistribution scheme.

So, the program for the rest of the week:

11.7 – Redistribution.  Use this scenario as a test-bed for redstribution, and investigate some of the challenges in the AK.

11.12 – “Router Management” was all about access roles.  I don’t know much about this, and I think it would be worthwhile doing some reading.

11.13 – Multicast.  This was about the MVR corner-case.  I remember this from last time I did this lab.  It looked a fairly simple configuration, but I totally failed to get it working.  Might have to get my Ethereal laptop out.

11.14 – QoS.  This exercise was fairly easy once I remembered how to do it.  It’s just that I don’t understand the point of the exercise.  They have set WRED thresholds for the four queues according to the DSCP.  But isn’t it the DSCP that determines (indirectly) which queue the packet goes in anyway? Their choice of DSCP values for the greater threshold are DSCPs that would normally go into only one queue.  Wouldn’t the task have made more sense if they had asked us to put AF11, AF21, AF31, AF41 into the threshold 2, and the rest in threshold 1 ?  How is this feature used in real life?


1 Comment »

  1. I found your site on google blog search and read a few of your other posts. Keep up the good work. Just added your RSS feed to my feed reader. Look forward to reading more from you.

    – Sue.

    Comment by Sue Massey — 09 Mar 2008 @ 23:01

RSS feed for comments on this post. TrackBack URI

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

Create a free website or blog at

%d bloggers like this: