Kevin Dorrell, CCIE #20765

03 Mar 2008

NMC Lab 09 Assessment

Filed under: General — dorreke @ 15:52

So week 09 is over, and so is Lab 09.  I have saved all my configs, and cleared down the rack ready for Lab 10.  I shall take Thursday this week as my training day, so in the mean time I would like to do an assessment of my performance in Lab09.  Perhaps “would like to” is the wrong way to put it!

I have dumped the SHOWiT configs into files, and I shall use WinMERGE to compare them with my solutions.  I am not expecting to come up with the same solution every time, but I am going to use WinMERGE to highlight the differences and to show me where to look.  I have made a grid of points for each section according to a rather arbitrary weighting, derived partly from experience and partly from guesswork.

Once again, this posting will not make much sense unless you can see the scenario.  So here goes:

9.1. Frame Relay

9.1.2. I had a spurious entry frame-relay map ip 172.16.10.4 104 on R1-S0/0.  That was the result of a careless cut-edit-paste.  I know it should have been DLCI 102 or DLCI 103.  It does make the interesting point, though, that R4 still saw the packets from R1 through this PVC, even if it did not have a map for it.  R4 still responded to the ping from R1.  -2 points.

9.1.4.  R2<–>R5 PPP.  The SHOWit has no peer neighbor-route on each side, and I did not.  I don’t think that matters, does it?

9.4. OSPF

9.4.7.  What is going on!!??  I failed to activate OSPF area 12 either explicitly on the R1-Tu12 or on Lo101 with the network command.  At the same time, I failed to put ip ospf network point-to-point on R1-Lo101.  I’m sure I remember doing that.  It’s like I am looking at an old version of the config.  -2 points.

On R2, I preferred to activate the OSPF on Tu12 with an interface specific command ip opsf 9 area 12.  I prefer to do it that way if at all possible.  In that way, it does not matter which interface I used for the unnumbered on R2.  In fact I chose Lo102.  It also leaves me free to choose the area number between R2 and R5.  I chose area 25.  That should be all OK.

9.6. EIGRP

I didn’t have EIGRP passive-interface Tunnel12 on R1.  This didn’t make any difference because there wasn’t any EIGRP speaker at the other end of the Tunnel.  I wonder whether I would have been marked down for that?  I shall assume not for the moment. 

IPv4 Redistribution.

I chose to inject 172.16.104.0/24 into EIGRP on R4 and let it go round the EIGRP.  In the SHOWiT, it is pre-empted by the OSPF version of the prefix in R3.  In the SHOWiT version, R6 would route up to R1 to get to the prefix.  In my version, R6 would route down via R3.  This is what I did on R3:

router ospf 9 
 router-id 172.16.103.1 
 log-adjacency-changes 
 network 172.16.10.0 0.0.0.255 area 0 
 distance 180 172.16.104.1 0.0.0.0

9.8. BGP.

I did not get the point about messing around with the weights (and still don’t, but it’s too late now) -2 points

9.10 Security part 1. 

Points: 0 out of 4.  I just did not do this section. It must have slipped my attention in my rather fragmented attempt at the lab.  “Luxembourg Nil points” (out of 4).

9.13 Security part 2.

Points: 0 out of 4.  I just did not do this section. It must have slipped my attention in my rather fragmented attempt at the lab.  “Luxembourg Nil points” (out of 4).  Looking at the size of the access lists on R3 on the SHOWiT, if I had to skip any section it should be this one!

9.14.  IPv6 

9.14.1. For some inexplicable reason I put the 17.::16.61:0/120 addresses on the Fa0/0.61 of R1 and R6 instead of on the tunnel interfaces.  It still worked, of course, but it violated the requirements.  -2 points.

9.14.3. Again for some inexplicable reason, I failed to put ipv6 ospf network point-to-point on R1-Lo101.  I really do not know how this happened because this is something I normally do as a matter of course.  -2 points.

9.14.4.  The SHOWiT has ipv6 ospf priority 0 on R2 S0/0.  If this interface is OSPF P2MP-NB, that command must be spurious.   I need to ask about this on DISCUSSiT.

9.14.9. I failed to include 172::16:106:0/125 in my prefix-list IPv6-RIP-Nets on R1, so I am questioning whether it was redistributed into OSPF.  I did have redistribute rip lab9 route-map IP6-RIP–>OSPF include-connected in R6, so I think it must have done.  But whereas I distributed it into OSPF on R6 only, they did it on R1 as well as R6.  I think I am OK because the requirements say that R3 should load balance towards non-RIP prefixes, but not, say CAT3 towards non-OSPF prefixes. 

Their show ipv6 ospf database on R6 does show 172::16:101:0/125 originated as type-5s from RIDs 172.16.101.1 and  172.16.106.1.  (Inconveniently, the SHOWiT does not have any show ipv6 route or show ipv6 ospf database on CAT3.  But it should be the same on all the routers in area 0.)

9.17. Address Administration.

Points: 0 out of 4.  I just did not do this section. It must have slipped my attention in my rather fragmented attempt at the lab.  “Luxembourg Nil points” (out of 4).

9.18. Multicast

I reckon it does not matter whether you put the ip pim nbma-mode on R2 or on R3 to pass the packets on to R4.  But I found that if you put it on both, then R4 gets two copies of each multicast packet.  I chose to put it on R2 only but the SHOWiT puts it on both.  In fact, the SHOWiT has ip pim nbma-mode on the s0/0 of all four routers.  See below.

I had a spurious ip pim dr-priority 2 left on R2-S0/0 from my messing around with multicast.  I don’t think it makes any difference in this scenario.

There are two points where I disagree with the SHOWiT on R4.  One is that they have ip igmp join-group 229.17.17.17 on R4-Fa0/0 as well as R4-Lo104.  I reckon that is cheating – it should be on R4-Lo104 only.  They also have ip pim nbma-mode on R4-S0/0, which I reckon is spurious.  No it isn’t!  That’s how they avoid getting the double response I was talking about two paragraphs ago!

Conclusion

All in all, I reckon somewhere between 60 and 70 points.  Too many points lost for stupid stupid stupid mistakes.

  Lab 09       2008 Wk. 09        
                          Points
  Section   Date   Start   Finish   Time   Max   Est
      Read-through       00:00   00:00   00:00        
  1   Frame Relay & Serial Interfaces   25/02/2008   21:00   21:27   00:27   6   4
  2   Catalyst Configuration   25/02/2008   21:27   21:53   00:26   6   6
  3   IP address configuration   25/02/2008   21:53   22:07   00:14   4   4
  4   OSPF   25/02/2008   22:07   22:27   00:20   6   4
  5   RIP   25/02/2008   22:27   22:30   00:03   6   6
  6   EIGRP   25/02/2008   22:30   22:38   00:08   6   6
      IPv4 Redistribution   25/02/2008   22:38   23:20   00:42   4   4
  7   QoS   not recorded   00:00   00:00   00:00   4   4
  8   BGP   not recorded   00:00   00:00   00:00   8   6
  9   IOS features   not recorded   00:00   00:00   00:00   2   2
  10   Security   not recorded   00:00   00:00   00:00   4   0
  11   NTP   not recorded   00:00   00:00   00:00   2   2
  12   IP Features   not recorded   00:00   00:00   00:00   2   2
  13   Security   not recorded   00:00   00:00   00:00   4   0
  14   IPv6   not recorded   00:00   00:00   00:00   8   6
  15   Catalyst 3550   not recorded   00:00   00:00   00:00   4   4
  16   Catalyst 3560   not recorded   00:00   00:00   00:00   10   6
  17   Address Administration   not recorded   00:00   00:00   00:00   6   0
  18   Multicast   not recorded   00:00   00:00   00:00   8   4
                               
      TOTAL               02:20   100   70
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