Sunday, August 30, 2009

3 Types of Network Designer

The following writing is still related with the CCDE Practical exam that I took recently. IMHO, there are three types of designer for network infrastructure solution:

Designer for Solution: the one normally focuses on the high level solution, by considering customer business model, future growth and other non-technical stuff. The coverage of the design is usually broad, but not too deep, and the solution is for a complete infrastructure with all the supporting components, including the operational process and the operation management. Solution designer should be able to provide the high level topology network infrastructure with the technology to be used and the features need to be enabled, but neither is required to provide the details nor the exact hardware to be used. Characteristic and the features required from the hardware can be mentioned though, to make it easier for the hardware selection by later designer.

Designer for Pre-sales: similar with solution designer, but the coverage normally is less broad and more detail to support the sales activity. As example, while the solution designer may covers the whole infrastructure including the operational process, the pre-sales designer may cover only the data center but can provide the detailed topology for it. The pre-sales designer is the one who involves in the hardware selection, and she must ensure the hardware chosen can run the technology or features required in the solution. If there is capacity and future growth requirement in the design, it has to be considered as well during the hardware selection. The output expected from a pre-sales designer is high level design with the list of hardware required called Bill of Material.

Designer for Implementation: the one who focuses on the in-depth and bit level details of the design. Implementation designer must provide the low level design and make sure the solution can really be implemented using the hardware available. The list of hardware may have been decided by previous designer, so now it's time to make the solution really works. The coverage of the implementation designer can start from the physical topology and connection, module allocation in the hardware, IP addressing scheme, software to be used, up to the detailed configuration of each hardware. The technology and the features chosen may need to be adjusted accordingly based on the limitation from the hardware or the software architecture. And the configuration or the way to implement the technology or features is usually based on the best practices, lab testing or the previous experience in another networks.

One example when to use the different types of network designer is as follow: a solution designer is the one who builds the Request For Proposal (RFP) document for a complete solution including the operational support. So he stands on the customer side. A group of pre-sales designers, stand on the vendor side, can work to answer this RFP and each designer must provide the list of hardware for specific area that complies with the requirement. It is required for the pre-sales designer to submit the proposal explaining the high level design and how the proposed hardware can deliver the solution. And once the proposal is agreed, the hardware need to be ordered, and now it is time for the implementation designer to really make the solution works.

Which one of the designers is better? It depends.

As in the above example I mentioned, we can be the ones who set the direction of the new network infrastructure solution and technology to be used without having to know too much detail but instead must cover broader technology, we can be the ones who select the hardware and provide high level design to support the sales, or we can be the ones who work in low level design to implement the solution and configure the devices.

Sometimes a person must work as solution designer and pre-sales designer at the same time. And sometimes a person must even work as those three types!

Before I joined Cisco, I used to work as the solution designer, pre-sales and implementation designer role and my role may changed from one project to the other. Obviously at that time, as solution designer I gain benefit being outside Cisco because I was able to work even with the hardware from multiple vendors. But as implementation designer, I was not able to go deeper because I didn't have access to the detailed hardware and software architecture.

Since I joined Cisco Advanced Services about 3 years ago most of the time my focus has been in the implementation or after the list of hardware has been confirmed by the pre-sales designer. I must deal with the design limitation due to the hardware or software architecture. Most of my customers are Internet Service Provider or from Telecommunication industry. And in my last several projects I had to focus on the migration from the existing infrastructure to the new one, which means I have to deal more with the right methodology and the detailed procedures to transform the network without impacting the daily business of the customer.

The CCDE exam that I took few days ago covers the knowledge owned by the solution designer, and part of the pre-sales designer. It deals with the high level solution design. It is not required to know the limitation from the hardware, nor it is required to choose the hardware like what the pre-sales designer does. CCDE contents cover the different type of customer networks from different industry, from ISP to Retail, Financial, Media and so on. We don't need to know the in-depth and bit level details of the technology but we must know the reason why a particular technology is chosen in the solution.

So looking at the above facts, please allow me to make this statement even I haven't passed the exam to prove it: it is actually possible to just walk in to CCDE practical lab, without preparation, and pass it. As long as we have extensive experience with high level design for different type of networks. Plus we need the problem solving minded, the ability to capture only the related and important information, and a good stamina to stay focus with lots and lost of reading within 8 hours.

For me, if I really failed this attempt and need to take the exam again, at least now I know what to do. I need to get out from my current mindset that follows my current work where it is expected for me to focus in a very low level and detailed design, with a narrow technology area. I need to return back to my previous experience before I joined Cisco, when I used to support the pre-sales activities, and when I used to work with high level solution of multiple customer networks from different types of industry. Since my current work deals only with Service Provider networks, I may need to find some best practices documents, but not the in-depth implementation practices, but more like the high level design solution for different type of customer networks.

All of those will be necessary once I get the report 6-8 weeks from now, stating that I really fail. So let's just wait and see.

Wednesday, August 26, 2009

CCDE Practical, What (I Think) We Need To Pass It

I've just taken the CCDE Practical exam. The result will come only after 6-8 weeks, and frankly I don't know if I will pass or not due to the way the questions are presented. Mind you there are many questions require to drag-and-drop, fill in the table/matrix, re-ordering, and adding device/link into the existing network diagram, and in CCDE exam partial credit is possible.

For me, the content and coverage of the exam were a bit unexpected. So I wrote the following based on my own experience taking the exam today.

We Need a Very Good Stamina
- Surprisingly for the CCDE I found the time is not the main issue, 8 hours should be enough because we can't go back to the previous questions or re-check our work anyway. We just need to make sure to do each scenario within the average time allocated (if there are 10 scenarios, just divide 8 hours with 10 to get the average time we have per scenario)
- But what we really need is good stamina to be able to stay focus and concentrate after reading multiple different scenarios and hundreds of questions!
- Nice sleep and good dinner/breakfast is compulsory (in my case, lunch provided at testing center was horrible! And I was unlucky, I didn't have breakfast in the morning)

We Need to Have Broad "Design Experience"
- I believe there won't be any book or training to face this exam, the best practices design document or case studies may help
- We really need to have design experience and analytical skills, not as low level designer but more like as 'high level' solution designer
- Our experience and knowledge should cover the design for different type of customer network and industry, from ISP to Enterprise like Retail, Financial, Media etc in order to understand not only the challenges with the design of certain network type, but as well as type of the applications run and the network requirements of those applications that may affect the design decision

We Need to Understand What They Want
- Even we have extensive and broad design experience, our logic must sync with what the exam authors wanted
- Sometime there is more than one right way to solve the requirement, but we need to know which one is the expected answer based on the information provided
- Similarly, for re-ordering question, we need to make the order based on related information and which is the most correct (and for me it's still difficult to figure out the "right" order since I believe there is more than one possibility of the orders as the answer)
- CCDE Practical Exam Demo can show a brief example, the Networkers 2009 slides from Russ White can even provide closer view of the real practical exam

We Need to be Able to Relate Only the Important Information
- There are lots and lots of information provided, sometime half of the information is not important (but we still need to read and screen it at least during the first reading)
- But sometime the information can be very minimum, for example, for some application it's assumed that we know how it works
- This is the point where we need the good stamina so we can still focus especially in the last few hours, we also need the ability to capture only the important and the keywords from the overwhelmed information provided, and possess a broad and high level design experience in different type of network and industry to make us familiar with the challenges

We Need to Do "High Level" Troubleshooting Too
- It seems like the exam maker thought it was not enough with only the number of design decisions we must do, we also need to do some "high level" troubleshooting
- We may be asked to figure out what's wrong with the network or design flaw causing network issues, and instead of doing debug we must analyze it from series of information provided (sometime we need to choose which questions and further information to ask to the customer)
- Again, I believe for this part we have to rely on the experience with high level design, the logic and ability to capture only the necessary information, and possess the knowledge of technology overview instead of in depth/bit level details since we can't do any debug

And In the End, When We Fail
- Unfortunately even if we fail we may not able to be more prepared in the next attempt
- At least in CCIE lab if we can't ping definitely there is something wrong with our setup, and after we fail in CCIE we are presented with the break-down score for each technology section so we know which part is our weakness
- The CCDE exam contains multiple scenarios and bunch of questions for each scenario. From one scenario the questions may cover the routing, security, tunneling, management and Quality of Services technology areas and personally I'm not sure how I can figure out on which part is my weakness if I really fail (unless the score report can break it down per technology area for each scenario)

In summary, I fully support the statement of CCDE practical exam is as difficult as CCIE lab, even their coverage is not in the same context. And it may be more difficult if we consider the fact that we won't know for sure if we make mistakes. Even I feel like the design knowledge required to pass is more on the high level, but the most important things to have are the designer logic, broad knowledge of technology areas and the ability to capture only the necessary information before making any design decision.

So I think we need the above points I mentioned to pass this exam. But I can be sure only after I got my CCDE number, either in this attempt or the next.

Here is a link to CCDE practical tips from another test taker.

Tuesday, August 25, 2009

Confession From London

I'm not ready.
I hate to admit but that's the fact.

I don't like to make excuse but let me try it once at least for this: after I got back from the previous project to Dubai last week I had only 6 days before the exam. And I used the first two days, obviously, to sleep and watch several HD movies, to compensate what I have missed during that hectic project.

So I had roughly only three days to review and read some books, and I was still managing the project remotely at the same time (it means lots of emails, webex meetings, phone calls, remote SSH session etc). Then this morning I took 8 hours flight to London.

As I said before, yes I'm really lack in my preparation but I'm not lack of confidence at all. But I guess I have to rely solely on my project experiences in the past and the knowledge I've gathered from the previous certifications.

Let's see how it goes.

Tuesday, August 18, 2009

Project Riyadh

- Vēnī, vīdī, vīcī. I came, I saw, I conquered.

This is my sixth week in Project Riyadh and hopefully the last. When I was told to be involved in the project the scope was: to lead the team to fix some design issues by migrating 15000 VPN customers in 3 weeks. My mind at that time was so focused to that number, and with a simple math considering the team can work continuously without a break it means we have to do 700 customers per night.

Once I arrived in Riyadh on the second week of July I realized the main challenge of the project is not to migrate the customers, no matter how many per night. There was lack of information and no documentation provided of the existing network and services. Network migration project relies on the information. Information of the existing network. Information of what the new network is going to be. Then we need to build a bridge between the existing and the new network. We need to build the methodology and procedure to ensure we can have a smooth transition period. The correct approach to make the migration process will not impact the daily business.

Without proper information, it's really difficult to come up with the right procedure. Without the right information, the methodology and the process can be misleading. No information, no bridge.

Fortunately I was and I am still surrounded by the best and talented engineers in the team. I remember Harry Stamper once said "I'm only the best because I work with the best". Like the Joe's, when all else fails, we don't. When any other team may refuse to continue working with a very less resource, lack of information and a very tight schedule, my team and I decided to continue the best we could.

We made mistakes in the first week but by making mistakes we learn more and more about the existing network. The customer environment is very unique so there is no way to finalize the migration process in the lab environment. We have to execute the migration and build the procedure at the same time. We are learning about how to migrate the network by doing it. Most of the team members worked more than 16 hours a day. And after few weeks, I was able to finalize the process, methodology and procedures, and I have all of those documented properly. Having a proper document of the migration process means anyone can continue my work even if I'm already out of the country.

This project may not make the top in my preferred projects list but I'm still happy because my team and I are able to accomplish something that was considered impossible. Yes I was not able to complete it in 3 weeks. Most probably it will be completed only by next week. But I communicated this frankly with the customer that due to the lack of information we have to share the risk. And one of the risks is we need more time to complete the project, especially I found there are many other services need to be migrated not only the VPN customers. I'm a kind of guy who doesn't like to make excuses. So to me what's important is to be clear and communicate all the challenges with the customer. And by working together as one team, anything is possible.

Yesterday was the independence day of my country. I hope my independence day from this project is coming soon too.

Those who have been following my blog should know that I have another important thing to do next week. Due to the high pressure from Project Riyadh, I didn't have time to prepare for it. But I will just try the best as usual.

Lack of preparation, yes. Lack of confidence, no no.

Project London, here I come.