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First day of new CCNP track

August 1, 2010 Leave a comment

If you missed it (god knows how its possible), today is the first day where ROUTE, SWITCH and TSHOOT exams are the only valid CCNP track exams. When I started this blog seven month back I looked at this date as a scary monster and now that it’s here, it feels great to know that I beat the deadline by couple of month 😉

If you didn’t complete your CCNP track by yesterday, your choices are limited to the exams listed above. Say goodbye to the old books, training videos and notes. For some part you’ll be able to use the old materials as some of the topics are either unchanged or expanded but big portions are outdated and should not be used anymore.

Personally I liked ISCW and ONT and learned a lot from each (mostly from ONT) but new times, new technologies and let’s face it – new business strategy for Cisco bring those changes. If you missed the deadline and stuck with a useless ISCW\ONT it kind of sucks but looking at the big picture I believe it is a good step for all of us as its updating the validity of our certification and make it harder to get (which for any certificate is a good thing).

Are you one of those who didn’t make it on time? Did you make it in the last week\day? Tell us your story

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SPF algorithm

March 6, 2010 Leave a comment

As I mentioned on my EIGRP Metric Lab, this post is dedicated to SPF algorithm and the cool  Dijkstra’s algorithm. I do not want to get too techie in this post, just to get the general concept. I’ll point you at the end of the post to some good in-depth reads.

Dijkstra's algorithm

OSPF and IS-IS are link-state protocols, they use Shortest Path First (SPF) to calculate distance between the routers and create the routing table.

For the SPF algorithm to work, it requires all routers in the OSPF\IS-IS network to know about links and all the other routers in the same network.

OSPF encode its link-state information in Link State Advertisements (LSAs) and floods it. IS-IS encode its information in a Link State Packet (LSP).

When the initial data collection process is completed, OSPF \ IS-IS process runs the Dijkstra Shortest Path First algorithm to find the shortest path from itself to all the other routers in the network. The same process happen on each router in the network. When the algorithm processing is completed, all the routers have a similar table and consistent routing can start.

How does it work?
Dijkstra algorithm put the router as the root of a tree and calculate the shortest path to each destination. While the overall picture on all routers is similar (they all have the same routers and links), each router look differently at the result as the point of view is personal. It is just like in life – you share a room with 3 other people, each one stand in a different corner. When you are asked to describe an object you describe the exact same object but it does look a bit different from different angels.

When any change is noticed (link state change), SPF start the calculation all over and re-build the map. OSPF ability to use many areas is a way to reduce these frequent updates as it has less routers per area. This is a major consideration when using a link-state protocol.

Two recommended reads that actually describe the shortest path calculation step by step are:
1. Example & descriptive explanation to how does SPF algorithm work in OSPF and IS-IS.
2. RFC 2328 is also a good read to get better understanding on the OSPF protocol.

EIGRP Metric Lab

March 5, 2010 Leave a comment

I spent the last week reading my notes, answering questions and digging in topics that I didn’t feel complete about. I start seeing the big picture and get closer to the exam. This post will cover EIGRP metric and the next one will cover the SPF algorithm, two subjects I found both interesting and major exam topics.

EIGRP uses a relatively complicated metric system as it has five parameters:
Bandwidth, Load, Delay, Reliability and MTU.

By default only Bandwidth and Load are being used (and we’ll see why later) but in more complex scenarios the composite metric is calculated using the K values of each variable.
Bandwidth – calculated as 10^7/BW (using Kbit), the lowest along the path is chosen
Delay – cumulative along the path, the sum of all the delays in tens of microseconds (ms).
This is tricky and important for exam configurations – for 1000 ms we type 100.

The formula to calculate the metric is

Metric=[K1*bandwidth+(K2*bandwidth)/(256-load)+K3* delay]* [K5 /(reliability+K4)]

Values K1 through K5 can be changed with the metric weights command.
The default values are:
K1 & K3 = 1
K2, K4 & K5 = 0
The zero value of K2, K4 & K5 explain why we only use Bandwidth and Delay by default as the formula zero shorten the formula:

Metric = [256 * (10^7/BW) + 256 * (delay)]

In order to see the metric output I’ve built a small lab with 3 full-mesh routers and some Loopback interfaces on one of them.
One way to see the metric value is the command show interfaces s0/0:

Serial0/0 is up, line protocol is up
Hardware is M4T
Internet address is 10.2.2.2/30
MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec,
reliability 255/255, txload 1/255, rxload 1/255

Another way is the show ip eigrp topology 10.0.0.0/8 command:

IP-EIGRP (AS 100): Topology entry for 10.0.0.0/8
State is Passive, Query origin flag is 1, 1 Successor(s), FD is 2169856
Routing Descriptor Blocks:
0.0.0.0 (Null0), from 0.0.0.0, Send flag is 0x0
Composite metric is (2169856/0), Route is Internal
Vector metric:
Minimum bandwidth is 1544 Kbit
Total delay is 20000 microseconds
Reliability is 255/255
Load is 1/255
Minimum MTU is 1500
Hop count is 0
172.16.20.2 (Serial0/1), from 172.16.20.2, Send flag is 0x0
Composite metric is (2681856/2169856), Route is Internal
Vector metric:
Minimum bandwidth is 1544 Kbit
Total delay is 40000 microseconds
Reliability is 255/255
Load is 1/255
Minimum MTU is 1500
Hop count is 1

I broke the lab with the shutdown command on one of the Interfaces.
Using the command show ip eigrp topology I was able to catch the Active state

P 10.0.0.0/8, 1 successors, FD is 2169856
via Summary (2169856/0), Null0
A 10.0.1.0/30, 0 successors, FD is 2681856, Q
1 replies, active 00:00:00, query-origin: Local origin
Remaining replies:
via 172.16.20.2, r, Serial0/1

Another lab breaking step was changing the metric values on one side only. Using the command metric weights 0 3 2 4 1 2 resulted in:

*Mar  1 00:35:16.935: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 100: Neighbor 10.2.2.1 (Ser
ial0/0) is down: K-value mismatch
*Mar  1 00:35:21.399: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 100: Neighbor 10.2.2.1 (Ser
ial0/0) is down: Interface Goodbye received

Normal show ip eigrp topology show another mysterious buzz word – serno

P 172.22.71.208/29, 2 successors, FD is 46163456
via 172.30.1.42 (46163456/45651456), Serial0.2, serno 7539273
via 172.30.2.49 (46163456/45651456), Serial2.6, serno 7539266

This is Cisco’s explanation: serno stand for serial number

Some other definitions that this post will not be complete without:
Feasible Distance (FD) – the best metric along a path to a destination network, including the metric to the neighbor advertising that path
Reported Distance (RD) – the total metric along a path to a destination network as advertised by an upstream neighbor
Feasible Successor – a path whose RD <  FD (current best path)

Finally, I want to recommend reading a great post on EIGRP with non-default K values. It is well written and have good examples.

Find more labs here

BGP Tuning Attributes

February 18, 2010 5 comments

Finished with my BGP video series and BGP module on the BSCI guide I’m overwhelmed, for the first time during my BSCI studies.

In my BGP Lab post I said it is not that bad (so far – I did say so far). Well, now it is bad. Tuning Attributes are lords of details and kings of optional parameters.
While each attribute make sense and nothing seem to be too complicated, it is the full concept with all its details that left me lost and unfocused.

Selecting BGP path is different and a much more complex process than any other protocol (at least in this exam). While RIP use hop-count, EIGRP uses Bandwidth & Delay (and break ties with Reliability, Load and MTU) and OSPF use cost calculations, BGP has 14 parameters:

  1. Ignore routes with an inaccessible next hop address
  2. Prefer the path with the highest WEIGHT
  3. Prefer the path with the highest LOCAL_PREF
  4. Prefer the path that was locally originated via a network or aggregate BGP subcommand or through redistribution from an IGP
  5. Prefer the path with the shortest AS_PATH
  6. Prefer the path with the lowest origin type
  7. Prefer the path with the lowest multi-exit discriminator (MED).
  8. Prefer eBGP over iBGP paths
  9. Prefer the path with the lowest IGP metric to the BGP next hop
  10. Determine if multiple paths require installation in the routing table for BGP Multipath
  11. When both paths are external, prefer the path that was received first
  12. Prefer the route that comes from the BGP router with the lowest router ID
  13. Prefer the path with the minimum cluster list length
  14. Prefer the path that comes from the lowest neighbor address

My study guide did not offer too many detail on each attribute and I found cisco.com to be useful and easy to read. For this one topic this is the source for details (and we all know that at exam day, passing is in the little details).

Now don’t get me wrong, this is the easy part…
When start using route maps it is cool as Jeremy repeatedly reminded me but there are so many options and scenarios…

I’m close to completing the study guide and video with only two (relatively) short topics: Multicast and IPv6. I hope to wrap it up before the end of the weekend and start reviewing the notes and make sure the black holes from round I are fully understood.

Exam tip:  Jeremy Cioara (of CBT Nuggets) said only attributes 1-6 are BSCI materials and that route-map configuration (for attributes) is CCIE level requirements.

ROUTE Cert Kit – review

February 5, 2010 2 comments

Don’t worry, this is not a mistake and I’m still taking BSCI.
Pearson Education where generous and sent me the Cisco Press CCNP ROUTE 642-902 Cert Kit for evaluation. I must say that I didn’t expect much and was surprised.

CiscoPress CCNP ROUTE Cert Kit

The kit include 3 items:

  • Quick Reference book
  • DVD with 6 hours with 15 labs
  • online flashcards access

The 128 page quick reference book is awesome. If you just finished your CCNA and want to get a quick look ahead this is an easy to read but not too deep resource. Going over the topics of the exam you definitely get the feeling of it without getting lost on details.

I was surprised to see the Branch Office & Mobile Worker Connectivity as exam topics as I just passed my ISCW. I am happy to see these topics in the CCNP track even on a smaller scale.

As the name indicate, it is a quick reference book and whether you’re starting your CCNP or working on CCIE it is useful and worth having around. As long as you remember that this is just a reference book it is a great book.

The video cover most of the lab requirements for the exam, it has many examples with live console. It is a good reference point when you get stuck with a problem and need quick guidance. Working on my BSCI I find  many of these labs very useful as the main routing protocols are still included in both exams.

Cisco Press try to get a bigger audience to this kit and included BSCI only topics in the labs. You can find topics like IS-IS and Multicast routing which are no longer included in the ROUTE exam but do show in the video. As a BSCI candidate this is a nice surprise (even if they re-used old materials) BUT watching that video’s introduction few times they fail to mention that IS-IS is not part of the ROUTE exam and I want to see the face on those poor guys who start by watching the video and do not realize that they study something they do not need…

I didn’t spend much time on the flashcards as I’m not familiar with the topics yet but it is a collection of questions, not a multiple answer format.

To summarize, this is a well prepared kit that cover more than the ROUTE exam, a  valuable item for BSCI candidates and anyone who want some basic knowledge. As a NYC subway rider I love the small book that I can carry with me and read back to back in few rides.
I do not like the price. This kit is only good as an extra study material and when you pay for the training materials (class, video, books) and the exam you’re invested so much that any additional cost should be considered carefully.

Check all my reviews here

BSCI or ROUTE – which exam fits you?

February 2, 2010 9 comments

Now that the ISCW is behind me I have to make a quick decision before I start working on my next exam: Which exam should I take?
Out of the 4 CCNP exams this is in my opinion the biggest, scariest and hardest to pass – which make decision-making harder.

It is a heavyweight championship and the two contestants are:
On the right corner, the 3 time champion with thousands of knockouts (am I next?), a 90 minutes\50-60 questions – The Building Scalable Cisco Internetworks (aka BSCI 642-901)

On the left corner, the rookie from Cisco’s training center, a 120 minutes\52 questions – The Implementing Cisco IP Routing (aka ROUTE 642-902)

Now let’s be serious and get rid of all the non-techie readers (sorry wifi).
What are the parameters that should lead us to the decision?
Which questions should be asked and what information do we need?

This is the information I’m looking for:

  • Exam topics (ROUTE, BSCI)
  • Study materials & Labs
  • Web support
  • Exam durability

Exam Topics
Cisco’s announcement
talked about more “real life” which stands for two things: removing topics like IS-IS which are going away and adding hands-on tasks on the exam.
The goal here is getting more capable CCNPs, not just reading and memorizing experts (when was the last time that you saw an IS-IS network?) but professionals who can take a router and make it work (using real world protocols).

With the new ROUTE exam, IPv6 is moving to the front as a major topic.
It will also present a new topic – Implement Layer 3 Path Control Solution.
Routing protocols still have a major part of the exam as EIGRP, OSPF and eBGP are in and expanded. It is not clear how much deeper we’ll have to dive with EIGRP and OSPF compare with the BSCI path, reading the syllabus it feels like same level of knowledge but many more labs.

The topics that BSCI include and being removed are IS-IS, BGP, multicasting and Implement Cisco IOS routing features (mainly DHCP, route filtering and route distribution)

Winner – if you feel hands-on is more important you’ll go with the ROUTE exam. If you appreciate knowledge and familiarity with many technologies BSCI is your winner

Study Materials & Labs
As the old guy around BSCI present endless resources: video training courses, classes with experienced trainers (the same trainers will be running the courses but ROUTE is new to them too) and a huge variety of books and lab scenarios. In addition, many web sites and blogs wrote about the BSCI over the years and are great addition to fill up gaps in the books, labs and videos.

On the other hand the ROUTE exam just rolled out and though some books are already available the major video resources do not have anything ready and it is not clear what is the required lab setup.

Winner – this is a knockout in favor of BSCI

Web Support
Talking about web support I point at you guys, those who spend time at the official Cisco forums, the Cisco Learning Network and hundreds of other Cisco related forums.

If you ever studied to any exam you know that the books and videos are good to a certain point but the knowledge of others is priceless. You can always find someone with a good answer and an understandable explanation to topics you can’t fully grasp.

As with class instructors, the forum users have lots of BSCI experience, many of them took the exam and know what is expected. They can point you to the important issues as ROUTE experience will only start building after March 10th and will take some time to build into a massive power.

Winner – once again and for similar reasons, a knockout in favor of BSCI

Exam Durability
When I say durability I talk about the long-term usability of the BSCI (and for this matter BCMSN is in the same boat). Cisco says that BSCI can stand for ROUTE but is it going to change?
I think not. Since the exam is only valid for 3yr period I believe it will be valid for as long as you have it. Cisco is too serious to trick you.

The other aspect is how future employers will see the new exam. Since we do not know how tough it will be and what exactly will be included in the exam, it is hard to predict but I think over time employers might prefer it for pure R&S positions but when the job is more versatile, the old path provide wider array of  knowledge and have an advantage.

Winner – if anyone has an advantage here it would be ROUTE by few points

Summary
While the new ROUTE exam holds a huge potential to becoming a serious hands-on measurement tool it is still too early in the process to see this advantage. Being an exam candidate you want to get the knowledge but be honest – you want to pass the exam and BSCI offer more resources to do so.

If you have a different point of view or you think I missed something, you are welcome to comment and spark the discussion.

New CCNP – the Books

January 25, 2010 Leave a comment

Quick note to followup on Cisco’s announcement from Jan 25th:
Cisco Press released a list of their new books for the new exams.
Training is also available with the major Cisco partners. Prices for ROUTE and SWITCH exams stay at the same level as before.
I did not see TSHOOT training available yet but per Cisco’s announcement video it this class would be 92% lab time.

Update:  Cisco Press has materials for the new CCNP exam already