Monday, July 23, 2007

CCIE Certification for Design

A New Cisco CCIE certification may be out there soon: CCIE Network Design

http://www.networkworld.com/newsletters/edu/2007/0716ed1.html

Sunday, July 22, 2007

Seamless roaming or How to get work done in the john

After a lengthy sabbatical, I am back with another wireless post to satiate your appetites. On the heels of Leo's intriguing post about consumer vs. enterprise class products, I thought I would chime in with the wireless slice of the pie and also explain one of the great features to emerge out of the enterprise wireless network- seamless roaming. It is something we take for granted, but a lot of thought goes into ensuring that all the employees stay connected to the wireless network as they roam around the campus and move from access point to access point.

Now some of you are scratching your heads and saying "I can do that with my current wireless network in my house and roam all the way to the backyard!" While that is true, and impressive, you aren't really "roaming" in the wireless sense. You might be physically roaming, but you are still connected to the same AP. In your office building, you might be connected to one AP near your cube, but when the meeting starts and you enter the conference room, you are connected to a totally different AP. If you notice, your computer jumped to an AP that had stronger signal- but you wouldn't notice if you had a cetrally managed wireless control system, whose job it is to manage all the APs and pick up wireless clients seamlessly as they move. Why is this important? Well, if you were to lose the connection to the network everytime you moved around the building, then things just wouldn't be working out very well. Soon, frustration would set in, and everyone would be complaining that they can't get any work done because the wireless network is so terrible. If you would like, here is an experiment to try at your home:

Set up two routers in different parts of your house and make sure that they cannot "see" each other. You should not be able to get any wireless signal where you are setting up the other AP.
Give them both the exact same parameters and start closest to one AP. When your computer associates to that AP, start to move towards the other AP.
As you get closer, you will notice that your computer drops off and has to reassociate to the other AP. You have lost the connection to the first AP and have started a whole new session.
No seamless roaming for you!


In the corporate world, this would not work and IT departments spend lots of time making sure that there is wireless capability everywhere in the building. Even if you have hundreds of access points, unless you have a way to have them talk to each other then you will not be able to seamlessly roam. It is a critical part to the wireless network and along with the site survey should allow you to provide your users with a level of service that rivals that of the wired network.

You might be asking "Why is this important enough to write about? Let's talk about security or Pam Anderson!" The simple reason is that one huge application of roaming is the Voice Over IP. As Wi-Fi phones become ubiquitous in offices and warehouses around the world, seamless roaming is going to take on a more important function in the wireless network. In order to maintain a jitter-free voice connection, you must have a sub-50 milisecond hand-off from AP to AP. There is no time for a disassociation and a reassociation since the call will be dropped. The client will look for the strongest signal and the network has to be able to accomodate that move from one AP to the other without dropping any packets. Everyone knows how embarrassing and frustrating it is to be on their cell phone and have the call drop while you are in the middle of a business meeting.

In order to ensure seamless roaming, it is important that a centralized wireless network be implemented in the organization, not only for management purposes, but because by allowing the wireless controller to manage all the APs, it will be able to handle the sub- 50 milisecond roam that needs to occur to ensure connectivity remains. We will explore the differences between the centralized and autonomous solutions in another posting, but for now be aware that the idea of seamless roaming is the one thing that can dramatically affect productivity in the workplace....along with your ability to work in the john.

Thursday, July 19, 2007

Where do consummer products and enterprise products differ?

The whole new iPhone boom made me think of a topic that's been out there for years: What is the difference between a consumer type of product, and an enterprise class product? Say for example, why do companies pay the extra bucks to go for an enterprise level product? why don't they go to Best Buy or Circuit City, and get an eMachines desktop for their employees? Instead they go and pay for expensive Lenovo Thinkpads.

This question arises in networking and IT departments almost daily. A 24 port Linksys switch sold at Best buy costs arond $100. Why does a 24 port Cisco Catalyst switch cost thousands of dollars instead?

Well, lets name a few things here. First, the enterprise product is usually built with industrial level components, whereas the consumer product is built with off-the-shelf chips from discount manufacturers. The consumer product components are of less quality than the enterprise class ones. Then, for example, the Linksys switch is made out of inexpensive chips and components, while the Catalyst switch is made out of industrial components that will last much longer, sustain parameters at higher temperature ranges, and have less probability of failure. That is OK for the consumer buyer. You don't need the Linksys router to last for 20 years.

Second, there is the support or maintenance. If you go for an eMachines at Best Buy, and the hard drive dies, then you are out of luck. If a company purchases Lenovo, there is a maintenance and support contract associated with the product, and in the case of the HDD dying, then Lenovo will provide another one at no extra cost. This is an example, of course; Support contracts vary per vendor.

Finally, some products are simply not design for an enterprise level, from a functionality perspective. Picture driving a Formula 1 race car to work every day. The F1 car is built with industrial type of components, but it was not design to be an every day car. Same thing happens with IT systems; a Cisco router has features and whistles that benefit a specific customer; but not necessarily a consumer.
This last reason is what caused my writing of this posting. Apple is coming with the iPhone, but is it really an enterprise product, or a consumer product? Is it a Toyota Corolla, or is it a McLaren Mercedes?

People want to have a balance between work and personal life. Can there really be a product out there that satisfy both? I think this is a very difficult task. After all, that's why marketing segments markets.

Friday, July 6, 2007

Beta participation? Why?

Tech vendors and manufacturers are always looking for beta testers. Specially companies that are perceived as innovators, and they consider innovation as a competitive advantage. e.g. Cisco, Microsoft, Apple, Oracle....

Beta testers are regular customers (or users) that try out products and features for free, and give feedback to the manufacturer in order to get a better product. The interesting thing is that both parties benefit from the symbiotic relationship: the vendor gets feedback from a real and un-biased customer, while the customer gets to have a direct and closer relationship with the vendor that can lead to free products, deep discount and even voice in the direction of the product.

Sometimes, when we think about beta programs, we tend to think of it as us being users, and wanting to see how the latest and greatest is. Take for example Windows Vista. Some people got a chance to enrol in the program, and had a chance to get a first look of vista. Others tried GMail for several months, before it became available as a full blown supported version. With enterprise level products, the coolness of a product does not produce any benefit. Real benefits come from, getting closer to the vendor, having a voting voice in new product functionalities, and gaining power over the vendor (reducing the barriers of entry)...