Published In September 2006
Which installation fits your needs?
Internet protocol (IP) continues to drive business, bringing new terms to the industry. “Real-time IP” is one term that isn’t necessarily new, but continues to cause electrical contractors quite a bit of confusion. In this article, we’ll explore the differences between near and real-time IP systems.
“On the basic vocabulary level, ‘real-time IP’ is the term used to describe any IP traffic that must be transmitted and received immediately with virtually no delay,” said Joan Vandermate, vice president of product marketing, Siemens. “At the core are data packets. IP transmissions can either be in real time or on delay.”
Voice communication is the only true form of real-time IP. That is because during an IP voice conversation, the transmission is instantaneous, and no lag time is noticed. The human ear can detect a two-tenths second delay and most people on a voice over Internet protocol (VoIP) call never experience this. When lag time does occur, it is due to a lack of bandwidth.
A slight delay
When choosing an IP system, it is important to decide if you need real-time IP or near real-time IP. Most forms of IP communication, such as instant messaging, occur in near real-time.
“‘Near real-time IP’ is another term,” said Vandermate. “Instant messaging is [near real-time IP]. It seems to be real time but actually is not. If it were real time, the person on the other end would see what you were typing as you typed it out.”
Instant messaging is not nearly as time-sensitive as voice, which is why it seems “instant.”
The most common form of delayed IP is e-mail. Like instant messaging, e-mail is not seen by recipients as the sender is typing, hence the delay. Video over IP can be both in real time and near real time.
“A good portion of it is not real time,” said Vandermate. “Streaming video is actually on demand, [although] most think it is real time, when it actually is not. The only real-time video is video conferencing, and that is the single most demanding form of real-time IP traffic. It is subject to packet loss like voice, but it also has synchronization issues as well.”
In a nutshell, real-time video over IP is pricey and sensitive. Video over IP is extremely hard to install correctly because it needs tweaking. Invest in a specialist who can help with the install, because some of the systems are more sensitive than others.
Getting geared up
The most instrumental part of a real-time IP system is the infrastructure.
“In order to build an infrastructure capable of handling real-time IP, you need to have very good cabling, which means Cat 5 or better,” said Vandermate. “You also need to have state-of-the-art electronics that know how to prioritize traffic, which means labeling certain IP packets as priority.”
The electronics instruct the IP systems how to move information, moving certain data packets in real time.
“You need to design systems so that there is enough bandwidth available to handle the data, like database and e-mail traffic, and also handle the voice traffic,” said Vandermate.
The ever-present bandwidth issue really rears its head when talking about real-time IP. Making sure that a system is designed with enough available and reliable bandwidth helps alleviate some of the common problems associated with IP.
Now that we’ve covered the differences between near real-time and real-time IP, you should have the knowledge to make an educated decision on what system is right for you. No matter what IP system you choose to install, make sure you fully understand all of the available options. EC
STONG-MICHAS, a freelance writer, lives in central Pennsylvania. She can be reached via e-mail at JenLeahS@msn.com.