Thursday, November 29, 2007

IE Mock Lab dissapointment

Taken from http://www.internetworkexpert.com/iemlcod-rs.htm

Manual Grading

The CCIE Lab Exam is not a multiple choice exam. Instead, it is a highly complex exam with advanced protocol interactions that more often than not result in subjective answers. For this reason we do not run your configurations through a grading script to simply compare them with the solutions that we came up with. Each of your solutions are meticulously checked by hand by our highly skilled CCIE instructors. Once your exam has been graded you will be sent a detailed score report from our CCIE instructors. Sections that are marked incorrect include detailed feedback as to why there were incorrect, and typically include additional links to outside resources.



detailed score report : It was a simple 2 page report with some comments on my errors
detailed feedback as to why there were incorrect : The largest feedback on a section was 27 words, the smallest 3
additional links to outside resources : I wish i could have seen them

Solutions Guides

In addition to the detailed score report and lab breakdown you will receive a solutions guide broken down on a task-by-task basis for each Mock Lab Exam that you take. With this solutions guide format there is no need to sort through long configuration files to guess which configurations correspond to which task. The solutions guides show you not only the configuration for each task but also give important "show" outputs and explain how you can verify that your configuration is functional per the lab requirements.


lab breakdown : nice to have it, but not when some sections are out of date (refering to 2005)


Post-Lab Support

Once you have reveiwed the Mock Lab Exam and solutions, it doesn't stop there. Internetwork Expert also offers free support for each of the Mock Lab scenarios on our CCIE Support Forum. In the real CCIE Lab Exam there is no outlet for getting more feedback on your performance. With our CCIE Mock Lab Exams you'll have the opportunity to ask our instructors why your work was graded a certain way, 24 hours a day!


the opportunity to ask our instructors : ...Still hoping to get an answer...


The good part: Excellent diagrams! Clever scenarios! Tough Tasks!


1st Mock Lab - 74 %

On past Friday i had my first Mock Lab attempt, which proved easier that expected.

I was expecting IGP redistribution in multiple points, IPv6 BGP/OSPF/RIP routing, DVMRP, etc, but most of the sections where quite "easy". That of course doesn't mean that i passed. I missed 10 whole points in the Bridging & Switching section, which is one of my favorites.

The reason? I was in a hurry to finish the first sections which i have more experience with, in order to have enough time to do the rest. But, many questions were tricky and passing through them in a hurry, proved to be the wrong method. I missed 3 points on a simple task (because i didn't configure a vlan) and another 4 points (in two other questions) because of the first error.

There were only 2 sections that i didn't know at all and i had to improvise (one proved correct with a minor error in an acl entry, the other totally wrong). Also there were another 4 sections that i had to look into the Doc CD. At least i have now learned to use the Doc CD more efficiently. It's surely invaluable in such situations.

Also, when i finished, i had only 30 mins left (according to the actual 8-hour lab, because in the mock lab you're allowed to exceed this time by 3 hours). So instead of looking back all the sections in order to verify them, i decided to reload all routers! What was even more disastrous, was the fact that i reloaded them all at the same time and i didn't look at their logs while booting.

The result? After the reload, something wasn't working as expected. After a quick search i found one router which seemed not to be running OSPF. I checked its configuration (thank god i had saved all my session locally) and i found that there were two "neighbor" commands missing! I added them and reloaded again. This time i watched the logs and there was an error message saying that this particular command is not supported on this kind of topologies (a bug? command is accepted while configuring, but it's rejected after reloading). So i saved my configuration and warned (through email) the proctor about this behavior.

The answer from the support department the next day was to post my "problem" on the forum and i'll get an answer there. Of course, after a week there's still no answer there. And after a quick search on their forum, i found out that many questions remain unanswered. Too bad, because i have heard a lot of good words about InternetworkExpert's training material. I wanted to test their Mock Labs and maybe buy their Workbooks, but this kind of support made me rethink it. If i have one question in the Mock lab (and gets unanswered), i 'll probably have tens in the Workbook labs. Anyway, i still have one Mock Lab from them. If they keep the same -high- price and/or wrong "attitude", i'll have to look at a different vendor.

Let's hope this Friday, i'll have something tougher. The goal still remains for something >50%.

Monday, November 19, 2007

1st pass finished - IE's sample lab finished

Yesterday i finished the 1st step of my CCIE preparation!!!!

I have read (once) all chapters from the lab blueprint and during the last 4 days i was trying to run the sample lab provided at IE's site.

My system is a Core2Duo E6550 with 2 GB ram running WindowsXP & Ubuntu 7.04 (through wubi). These are the conclusions i came into after finishing the sample lab on Ubuntu (WindowsXP was too memory hungry):

1) 2 GB ram in Linux are more than enough to run 14 routers with full configuration ("ghostios" option used).

2) You have to change the idlepc value for each router after major reconfigurations, in order to keep the cpu load as low as possible (i used htop for monitoring it).

Regarding the 2nd one, this is what i did:


  1. Configure all routers/switches without any idlepc values.
  2. Start the switches one by one, finding a idlepc value that keeps the cpu load around 0-1%.
  3. Save the idlepc value to the router portion of the net file ("idlepc save R1").
  4. Start all the switches (you must now have idlepc values for all of them) and begin configuring L2.
  5. As soon as cpu load goes above 5%, stop one switch at a time, in order to find which switch causes the high cpu load due to the new config (you have to save the configuration very frequently and don't use the confg parameter in the net file).
  6. Stop dynagen, go into the net file and comment the idlepc value (which was stored before) for this particular switch.
  7. Start dynagen again and try to find the new idlepc value for this switch.
  8. When you find it, save it like in step 3.
  9. Repeat steps 2 though 8 in order to have all switches with full L2 configuration and cpu load around 2-3%. The lower the better.
  10. Then start the routers, repeating the same steps like in the switches.
  11. If later you change a switch in order to add L3 functionality, then you have to repeat the whole "find the idlepc value" process again for this switch.
  12. Finally start the BB routers and repeat the same process. These should be easier, because you don't have to change many things there.

I found out that most of the times, idlepc counts around 50 are the good ones, despite what dynagen says. Try changing the idlepc value (choosing 1 out of proposed 10) until you get 5%-10% cpu load for all currently running routers/switches.

I had to repeat the "find the idlepc value" steps 3-4 times for each router/switch, until i finished the core part of the lab (just before IP Multicast). At that time, cpu load was around 7-10%. After that, there was a minor increase for the extra configuration till the end, but that didn't have any impact on the L2/L3 functionality. If i didn't change the idlepc values, then when the cpu load was going above 70%, i was having L2/L3 issues with routing protocols reseting, interfaces going down, etc.

When i finished the lab, i noticed that having all routers with full configuration caused a cpu load around 20-30%, sometimes peaking to 50% (probably due to the BGP scanner and/or the "wr mem" command). I guess, that could have been lower, if i was experimenting with the idlepc values while being at the final config.

I had many cpu issues when i was using the access server (TermServ) to access the routers. Maybe console access through it or traffic passing through the tap0/br0 interface in linux, is causing increased cpu load. I decided to use the -default- tabbed xterm from Gnome (it was a little annoying closing/opening windows, but it worked fine).

I met a lot of issues with 3640s as switches running 12.3(14)T7. I changed them to 3725s running 12.4(17a) and everything worked fine till the end.

PS: There were some times that, while starting dynamips, the whole system became stuck (cpu load 100%) and i had to reboot it. I still don't know what was causing this (i haven't checked if dynamips has reported something on its log). If dynagen was successfully started, then everything was working fine afterwards.

Note to dynagen/dynamips authors: A feature to find/change the idlepc value, regardless if it's already known, would be a welcome addition. Then i wouldn't have to stop/start dynagen after each change in the net file (while trying to find the best idlepc value).

Note to IE's sample lab authors: There is an issue (probably in the initial config) with a BB router not having eigrp authentication configured, when starting. I had to manually change it.

For those who are wondering how i did in the sample lab... i failed with 70%. But i'm quite satisfied, because all the tasks i missed where due to me not understanding the exact meaning of a subtask, or providing wrong values (bits vs bytes) due to oversight. And on Friday i have my first mock lab...50% is the goal.

Tuesday, November 13, 2007

Progress 13-Nov-2007

According to the Lab Exam Blueprint, i have covered the following topics until now:

  1. Bridging and Switching
    1. Frame relay
    2. Catalyst configuration: VLANs, VTP, STP, MSTP, RSTP, Trunk, Etherchannel, management, features, advanced configuration, Layer 3
    3. Tunneling

  2. IP IGP Routing
    1. OSPF
    2. EIGRP
    3. RIPv2
    4. IPv6: Addressing, RIPng, OSPFv3
    5. GRE
    6. ODR
    7. Filtering, redistribution, summarization and other advanced features

  3. BGP
    1. IBGP
    2. EBGP
    3. Filtering, redistribution, summarization, synchronization, attributes and other advanced features

  4. IP and IOS Features
    1. IP addressing
    2. DHCP
    3. HSRP
    4. IP services
    5. IOS user interfaces
    6. System management
    7. NAT
    8. NTP
    9. SNMP
    10. RMON
    11. Accounting
    12. SLA

  5. IP Multicast
    1. PIM, bi-directional PIM
    2. MSDP
    3. Multicast tools, source specific multicast
    4. DVMRP
    5. Anycast

  6. QoS
    1. Quality of service solutions
    2. Classification
    3. Congestion management, congestion avoidance
    4. Policing and shaping
    5. Signaling
    6. Link efficiency mechanisms
    7. Modular QoS command line

  7. Security
    1. AAA
    2. Security server protocols
    3. Traffic filtering and firewalls
    4. Access lists
    5. Routing protocols security, catalyst security
    6. CBAC
    7. Other security features

This week i'm not working, so i'm moving faster through the topics. BGP was quite difficult to me because i have very little experience with it. Also redistribution was another topic where i found out how wrong i was about a lot of things that i had taken for granted.

Usually i spend 4-6 hours per day on the CCIE preparation during the days i'm also working, but this week i'm reaching around 10 hours per day. As time passes by, i'm getting more & more worried about not being ready in time. The biggest problem is that it is too much information to remember. And if you don't practice it, you won't remember it after some days.

So practice...practice...PRACTICE...until you start seeing dreams with routers & switches while you sleep.

According to my schedule, i should finish the 1st pass of all topics just before the weekend, so i'll use the 2 weekend's days to practice a whole 8-hour lab, but without being constrained by the actual clock. First i need to understand completely all the topics and then to be fast enough to configure/verify/troubleshoot them.

I'm also looking for renting some time on online racks, because Dynamips doesn't help a lot with the switches stuff. You can do the basic stuff, but many advanced features are not available for the NM-16ESW module.

Sunday, November 4, 2007

Progress 04-Nov-2007

I have bought some CCIE books and i'm reading their chapters according to to the CCIE Lab Exam Blueprint.

Until now i have covered the following topics :

  1. Bridging and Switching
    1. Frame relay
    2. Catalyst configuration: VLANs, VTP, STP, MSTP, RSTP, Trunk, Etherchannel, management, features, advanced configuration, Layer 3
    3. Tunneling

  2. IP IGP Routing
    1. OSPF
    2. EIGRP
    3. RIPv2
    4. IPv6: Addressing, RIPng, OSPFv3
    5. GRE
    6. ODR
    7. Filtering, redistribution, summarization and other advanced features

  3. BGP
    1. IBGP
    2. EBGP
    3. Filtering, redistribution, summarization, synchronization, attributes and other advanced features

  4. IP and IOS Features
    1. IP addressing
    2. DHCP
    3. HSRP
    4. IP services
    5. IOS user interfaces
    6. System management
    7. NAT
    8. NTP
    9. SNMP
    10. RMON
    11. Accounting
    12. SLA

  5. IP Multicast
    1. PIM, bi-directional PIM
    2. MSDP
    3. Multicast tools, source specific multicast
    4. DVMRP
    5. Anycast

  6. QoS
    1. Quality of service solutions
    2. Classification
    3. Congestion management, congestion avoidance
    4. Policing and shaping
    5. Signaling
    6. Link efficiency mechanisms
    7. Modular QoS command line

  7. Security
    1. AAA
    2. Security server protocols
    3. Traffic filtering and firewalls
    4. Access lists
    5. Routing protocols security, catalyst security
    6. CBAC
    7. Other security features

I hope i can move faster by the end of next week, when i'll have more free time. Surely there are a lot of topics that i haven't covered yet, but i already know a few things about some of them from my work experience. So i hope i'll move quickly over them, when their time comes.

In the meantime i have booked 2 Mock Labs for the end of November. I know i won't be ready by then, but i need to find out if i have understood the topics i have already read and to experience the difficulty of a real lab, since all these Mock Labs are said to resemble the real CCIE lab. If i get something above 50%, i'll be quite satisfied.

 
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This work is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 Greece License.