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July 2007 | Volume 10 / Number 7
Feature Articles

Best Practices for Selecting IP Endpoints for Your Converged Network

Eric Lewis, Paul Smelser and Craig Burger

Convergence - Who knew the application of this single word could bring such change to networking? Where will convergence stop? No one is sure. However, one thing is certain - IP will lead the way. This paradigm shift has caused us to not only rethink the way we design and implement our networks themselves, but the endpoints we choose as well.

First the basics. . . what is an IP endpoint? Well, one of the best definitions we uncovered was that of Roger Kay from Endpoint Technologies. He defines an endpoint as “devices that live at the network (TCP/IP) edge, are usually operated by a single user, and often have a human interface.”

That definition seems somewhat broad, and it is for good reason. Before the acceptance of converged networking, the number of IP endpoints was limited. In fact, if you had asked someone to define an IP endpoint at that time, they would have likely said a PC, Server, or Network Printer. Today, that just scratches the surface.

Today the list of IP endpoints is growing daily. But even with some of the more popular endpoints like IP phones, Wireless Access Points, etc., how do you know which one to choose? Below are a few guidelines for selecting some of the most popular IP endpoints.

First, regardless of the IP endpoint you are evaluating there are some basic considerations:

•Cost - Cost is not just measured in the initial purchase price, you must also consider warranty, support, and licensing fees associated with these products. Also evaluate mandatory maintenance contracts, etc. that add to the Total Cost of Ownership of the product.

•Features - Make sure the device offers the features you NEED for your network implementation and business size. Many devices will offer what you need plus a host of features that you may never use in your network. These usually come with a lofty price tag as well. The bottom line is this - if you don’t have a reasonable expectation for using the feature then don’t pay for it unless you don’t have another option.

•Powering options - You need to find out how the device is powered. For instance, if you are selecting an IP telephone or Access Point, does it accommodate Power over Ethernet (PoE) or does it require local powering? This fact alone will drive many decisions regarding location of devices, network power consumption, etc. Based on your endpoint selection, you may also need to purchase or replace other elements in you network to accommodate the requirements of the endpoint.

•Standards-compliance/interoperability - Is the device standards-based? Will it work with the other devices on the network and function correctly?

•Warranty - What type of manufacturer’s warranty comes with the product? Especially in cases where there is a sizable investment, you want to make sure that your product is backed by the manufacturer in the event of defects.

•Service and Support - If your network is critical to your business operation, you may want to purchase extended service and support. Look for plans offered by the manufacturer that provide various levels of service and response times. These will typically allow you to get the service you need at a cost you can afford.

With these basic parameters in mind, there are some additional things you might want to consider with two of the most popular IP endpoints: IP phones and Wireless Access Points (WAPs).

IP Phones

The number one item to examine in this category is cost. Depending on the size of your business, you could spend more money on phones than the actual phone system. Therefore the cost of the end point is a key consideration. With many IP PBXs today, businesses can spend between $600 and $1,000 per employee just for the initial installation. Those dollars add up quickly, especially for small and mid-size businesses.

Features of the IP phone are another consideration. While this may seem elementary, it is not. There are a wealth of features and button/line options available and today, of course the more features and buttons, the higher the cost. Some features warrant close evaluation and should have a greater impact on the buying decision.

First, determine if the phone is manufactured or supported by the IP PBX vendor. If so, chances are the phones are fully interoperable with the system, meaning that phones are fully configurable from the IP PBX system, and the features available with the phone are supported by the PBX. If not, interoperability and feature support may be a factor. Next, you will need to insure the phone supports the VoIP signaling protocol of the IP PBX , i.e. SIP, MGCP, H.323, or vendor proprietary.

License Fees are also a consideration when adding phones to the system. Does the IP PBX support additional phones without the need of purchasing additional licenses? If so, many licenses fees can only be purchased in “Packs”, meaning you could be forced to purchase a 10-seat license Pack to simply add one phone. This should also be a consideration in the overall TCO when making a purchasing decision.

Powering is also at the top of the list. Is the phone 802.3af compliant or does it require wall power? This will affect the physical location of the phone and could impact the power budget for the entire network.

Everyone wants a phone with good voice quality. This makes CODECs are a major issue. IP phones should support both a low bandwidth and high-bandwidth CODEC for optimum clarity and voice quality. Look for products that at least support G.711 (toll quality) and G.729 (low bandwidth for remote phones).

Management and configuration are two areas to consider. Make sure the IP phone you select is easy to manage and configure. Many models on the market today require a trained professional for installation and configuration, requiring phone configurations to be manually changed via text or XML editor, while others offer a user-friendly Web-based Graphical User Interfaces making them simple enough for almost any user to configure.

After you have examined each of these items, don’t forget to take a close look at some of the basic features. While these are sometimes easy to take for granted, they can make a huge difference in the users experience and therefore should be considered prior to purchase. Display - How large is it? Is it in color or black and white? Does it offer a backlit display? Line Keys - evaluate the number of keys offered and make sure it is adequate for your needs, both now and in the future. Color - While this may seem trivial it can make a huge difference in certain settings. For instance, most medical offices request white phones because of their “clean” appearance. On the other hand, a retail counter location may request a black phone so that dirt won’t be as evident. Also look at expandability. Can this phone accommodate an attendant console or button expansion module? Shared line appearance is especially helpful in smaller offices where there is no receptionist and everyone needs the ability to answer incoming calls, or view the status of the “lines” from any phone. Busy lamp field w/Direct Station Select (DSS is another useful feature for determining if internal extensions are in use or idle.

Wireless Access Points

You can’t go to a restaurant, book store or coffee house these days without seeing a sign on the door for Internet access or WiFi. The increased demand for wireless connectivity has made WAPs commonplace in today’s network architectures. However, as with most networking equipment, not all WAPs are created equal. Here are a few guidelines for selecting business-class WAPs.

Management is a key feature. Be sure to determine if the device is managed locally or through a centralized controller. Those managed through a centralized controller can be beneficial, particularly in situations where multiple WAPs are in use.

Powering options also need to be considered in selecting the best WAP. Know if the WAP you are considering is PoE powered or requires wall power. Many WAPs are placed in locations where wall power is not readily available or where it would be cost prohibitive. Also look at power consumption to make sure your power budget can handle the devices you have selected.

Security is a must. Make sure the device you choose offers WPA2 to secure your transmissions.

The number of WAPs you need and the amount of overlapping coverage required will be determined in most cases based on the physical environment. For instance, metal buildings may require access points or more overlapping coverage than buildings constructed out of brick or wood due to metal’s reflective characteristics. Also note that all coverage areas are not created equal. Make sure the device(s) you choose will adequately cover the area you wish to serve. Depending on the type of WAP selected, you may need more devices to cover a specified area. Also be mindful of the issue of directional coverage. Many WAPs require an antenna to broaden their overage range. Support for standards like 802.11a/b/g is also important in determining bandwidth usage.

Wireless QoS capability is also an important factor to consider. To properly prioritize voice and video data on your wireless network your WAP should include WMM support.

Do you need an integrated or standalone WAP? This all depends on the application. If you are looking to cover a smaller, confined area or have limited hardware space an integrated WAP may be the perfect solution. There are also situations where there are going to be many WAPs and a portion of the service area can be handled by an integrated WAP. Standalone WAPs are commonly used to easily extend the reach of your wireless network.

Cost is always a factor, but should not always be the driving factor. The WAP you purchase from your local electronics store is fine for home-based applications, but in most cases, they are not designed to offer business-class service or features. So, less is not always better. Management is another key issue that separates WAPs. Business-class WAPs will typically offer management capabilities, some even with Web interfaces for ease of use. The ability to centrally manage multiple WAPs is especially important in situations where you have multiple WAPs deployed. Keep in mind that business-class features will carry a slightly higher price tag, but will offer better results for you and your customers.

As convergence continues to take hold in business networks, the list of IP end points will continue to grow. Regardless of the type of IP end point you are selecting, evaluation of the basic criteria outlined above will allow you to make a fair comparison of the available choices and hopefully choose the product that is perfect for your application. IT

Paul Smelser is ADTRAN’s Product Manager, IP Telephony; Eric Lewis is Product Manager, Wireless and Security Products; Craig Burger is an Applications Engineer specializing in IP Telephony solutions, also at ADTRAN, Inc. For more information, visit the company online at

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