Voice of IP benefits and difficulties in a nutshell

By ServerWatch Staff (Send Email)
Posted Dec 13, 2000


Bart Teunis

Abstract

One of the hottest things at the moment is Voice over IP (VoIP), which has made fast progression this year, in both technologies as the quality of the delivered voice. VoIP has several benefits, but has also several difficulties to overcome. In this article I will outline some of the benefits of this concept as well as some of the difficulties.

What is VoIP?

One of the hottest things at the moment is Voice over IP (VoIP), which has made fast progression this year, in both technologies as the quality of the delivered voice. VoIP has several benefits, but has also several difficulties to overcome. In this article I will outline some of the benefits of this concept as well as some of the difficulties.

The first question that we can ask, is it new? The answer can be very short No, but why this major interest during the past year. The answer to that question is also very simple. What we see is that we get more and more bandwidth available and that the price for bandwidth is decreasing. Research done by the Gartner Group points out that : " WAN usage in Europe will grow 500% but prices decrease by only 30% resulting in a 300% increase WAN expenditures" VoIP uses the IP protocol to carry voice-packets over an IP-network. The voice-signal is segmented into frames and stored into voice-packets, these voice-packets are transported using IP in compliance with the International Telecommunications Union-Telecommunications (ITU-T) specification H.323, the specification for transmitting multimedia (voice, video and data) across a network. Because it is a delay-sensitive application, you need to have a well-engineered, end-to-end network to successfully use VoIP.

What are the benefits?

Although there are many more benefits i just outline a few

  1. Infrastructure Because VoIP can use an IP network, there is no need for a separate Voice network. You can wire your building with one cable and use this for both voice as data. As we all know at the moment every building has it's own LAN. For external voice traffic (WAN) you can use your data line (IP-trunking) for connecting a branch office to the HQ, you only pay cost for the rental line, which is a fixed price most of the times.
  2. Redundancy Because VoIP can use a distributed device setup where as a traditional PBX is using a centralized setup, you're able to build up a more redundant solution.
  3. Management Because the VoIP devices using the IP protocol (whether it is a IP phone or a CTI-terminal) it is just another IP-device you connect to your IP backbone. The management can be done by your IT staff

The things to overcome!

  1. Infrastructure: Do you have enough bandwidth available to support this kind of traffic on your LAN/WAN ?Further, because it is a delay-sensitive application, you need a well-engineered, end-to-end network to successfully use VoIP. Fine-tuning your network to adequately support VoIP involves a series of protocols and features to improve quality of service (QoS). Traffic shaping considerations must be taken into account to ensure the reliability of the voice connection.
  2. TCP/IP. The current version of TCP/IP was not designed for services as VoIP. It works but it takes the IP-protocol to the boundary. With IP v6 there will be more improvement for multimedia applications.

What's on the market ?


Although there are a lot of vendors with VoIP solutions, I only mention the ones which I'm familiar with:

  1. Cisco. Cisco offers an solution based on their 1750 router with Voice Interface Cards (VIC's) and a call manager running on NT v4.0 or W2K server. Plus, if the call manager gets down the call will stay. Minus if the call manager is down no calls can be set up.
  2. Matra Nortel is offering a solution based on W2K server, they took their software from the traditional PBX and made it ready for W2K server. It is mainly a software based solution
  3. 3Com has it's NBX which is running a voice over Ethernet protocol and can handle up to 100 user on one box. Plus the OS is based on UNIX, minus the voice over Ethernet is a 3Com protocol and not an open standard

Conclusion

In my opinion is VoIP a good concept and offers a good solution for getting control on your costs and management. The market is ready for it and the benefits are greater than the difficulties.

Literature

1. "Succesfactoren VoIP onder de loep", dec. 2000 Hein van Steenis, Telecommagazine
2. "IP convergence", oct. 98 Susan Breidenbach, NetworkWorldFusion
3. "Voice-over-IP Overview" Cisco systems
4. "Packet Voice Networking" Cisco systems

 

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