Connection Issues


Because it relies so much on Internet bandwidth, VoIP will definitely let you know when all is not well with your Internet connection. You might have occasional gaps in your communications; dropped calls; or even fast busy signals, which are generated by your telephone adapter (TA) when it cannot locate your VoIP provider.

In this section, I cover the most common connection-related issues you might encounter.

Note

If you select low bandwidth settings, you may override them when dialing by dialing the *99 code before making a call. This allows you to have bandwidth-saving settings for most uses but program your fax machine to dial *99 to enable high quality for better fax transmissions.


Bandwidth

Bandwidth is the holy grail of Internet communications. Geeks like me often joke that they will work for bandwidth. It enables us to download programs, music, and movies without long waits. It allows us to communicate in real time using voice and video. When it is gone, we are left with jerky pictures, spotty audio, and slow Web pages.

Insufficient bandwidth affects your VoIP communications by starving your voice codecs and impeding signaling protocol function. In extreme cases, you may find it impossible to make or receive calls.

Using Alternative Codecs

One strategy for dealing with bandwidth challenges is to use alternative codecs designed to use less bandwidth. You can cut your demands on your Internet connection from 90 Kbps to as little as 30 Kbps by choosing a low-bandwidth codec.

To change your codec, you might have to use your VoIP provider's Web site or configure settings in your TA. The exact procedure will vary by provider.

To change the codec for Vonage, you can access the Bandwidth Saver configuration page on the Vonage customer Web site (Figure 6.1).

Figure 6.1. Changing Bandwidth Saver settings on the Vonage customer Web site


Managing QOS Settings for Gateways

TAs need a certain amount of bandwidth to be able to do their job. How you connect your TA to your network can affect your calls. If your TA is connected behind a gateway, for example, it will share Internet bandwidth with any other computers and devices that also use the gateway. Uploading or downloading large files during a call can cause problems unless you can configure your gateway to reserve bandwidth for your VoIP calls. This reservation process is called quality of service (QoS) management.

By designating one port that has preferential service levels, you can effectively reserve bandwidth for VoIP communications (Figure 6.2). This reservation is effective whenever there is traffic on that port. At other times, all other ports have unrestricted use of your gateway's bandwidth.

Figure 6.2. A Linksys WRT54G gateway configured to provide QoS preference to Port 1


Gateway QoS configuration varies by manufacturer. Check your user manual to learn how to set QoS on your gateway.

Managing QOS for Combination TA/Gateway Devices

Gateways that include TA functionality include QoS settings that can be set to provide QoS preference to the VoIP potion of the device over the network ports. The Linksys RT31P2 allows you to enable QoS separately for the voice portion of the device or the network portion of the device (Figure 6.3). Enabling QoS for voice will cause the TA portion of the device to receive preference for bandwidth allocation.

Figure 6.3. A Linksys RT31P2 TA/gateway configured to provide QoS preference for voice


Intermittent connection loss

Occasionally, you will have calls drop for no apparent reason. If this happens once a week or less, it may not be a reason for concern (probably just stray radiation from outer space!). If it happens more frequently, however, you might consider the possible causes listed in this section.

Packet Loss

Internet Protocol (IP) relies on the delivery of pieces of data called packets to make communications successful. When packets do not reach their intended destination, they leave a gap in the data reception. Drop a few packets, and you might miss a few milliseconds of conversation. Drop half of all packets, and you will probably lose the call.

There can be many reasons for packet loss. Almost all of them will be traceable to problems with your Internet access provider or loss of an Internet router between you and your VoIP provider. If you wait an hour and everything is fine, chances are that the downed router has recovered or has been taken from active routes on the Internet. Longer outages probably point to issues closer to home and should be the topic of a call to your Internet access provider's support line.

If packet loss is a frequent problem with your Internet service, you might consider finding a new one. Check out other providers in your area. Check their reviews on Broadbandreports.com, if possible. Ask for a trial period during which you can evaluate the provider's service before canceling your current one. If the dropped calls go away, make the switch.

PPPOE Issues

Point to Point Protocol over Ethernet (PPPoE) is the means that many Internet access providers use to prove you are an authentic customer when you connect to their systems. A user name and password are typically programmed into the Internet modem or your gateway device and sent to the provider's system when you connect.

Many Internet providers limit the length of time you can remain online when no traffic is being passed. Because PPPoE connects so quickly, providers can safely drop your connection, and you'll never notice. By the time you have launched your Web browser to surf the Web, the PPPoE connection is reestablished, and you can happily surf away.

This is not the case with VoIP, however. What if you were to receive an incoming call while your connection is down? You're right: Nothing. It is also possible that an improperly configured PPPoE setup might drop your connection even when you are using it. If you are browsing the Web, you might notice a few seconds of delay loading a page but might not think anything of it. If you are on a VoIP call, you will definitely notice. You may even have calls drop out as frequently as every minute or so.

Check your PPPoE settings, if you can (Figure 6.4). If you have the ability to enable Keep Alive settings, try doing that, and see whether the connection stays up. If it still drops periodically, call your Internet provider's support line to enlist help with determining the reason for the connection loss.

Figure 6.4. Enabling Keep Alive settings on a Linksys gateway


Unstable Connection

If your connection never drops completely, but you seem to have intermittent periods of poor communications, check the QoS settings of your gateway. Intermittent downloads for antivirus software updates, incoming e-mail, instant messaging updates, and other causes can sap the bandwidth from your VoIP sessions if QoS is not ready to protect it.



Fire the Phone Company. A Handy Guide to Voice over IP
Fire the Phone Company: A Handy Guide to Voice Over IP
ISBN: 0321384865
EAN: 2147483647
Year: 2004
Pages: 94
Authors: David Field

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