Wednesday, January 10, 2007
by Jeff Hicks
Voice over IP (VoIP) is a hot topic in enterprise networking - mostly because it's a challenge. In implementation, VoIP employs a number of different protocols, and has a unique set of performance requirements that make it a challenge for any data network. Examining VoIP protocols should give someone a basic idea of the performance requirements that VoIP places on the network.
First, there's call setup, which sets up everything needed to make the telephone connection between the caller and the recipient (or “callee”). This requires protocols that enable dial tone, number lookup, ringing, and busy signals before the call even occurs. In addition, the call setup protocols handle things that happen after the call - any resource cleanup and statistic reporting.
Call setup protocols use either TCP or UDP to transfer data during the setup and takedown phases of a telephone call. The messages are sent back and forth between the caller, recipient, and call server using well-known ports. For calls that travel between the VoIP network and the Public Switched Telephone Network (PSTN), the call server will converse with a VoIP gateway using the call setup protocol. There are many different call setup protocols, some standardized and some proprietary. Let’s discuss a few of these.
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Continue reading "VoIP Protocol Basics, and Why VoIP Consumes More Bandwidth Than You Might Expect." »
Thursday, January 04, 2007
On NetQoS's internal boards, this news item from ZDNet prompted a discussion over Net Neutrality; and we had various questions and concerns about how recent developments would impact the Internet and our position as a network monitoring company. Below are some of the most insightful comments from the discussion that ensued.
We try our best to fairly present both sides of the argument, and this blog (and NetQoS) does not have an official endorsement for or against Net Neutrality legislation. We invite any and all who agree or disagree with any of the points our panelists make to comment and let their voices be known. We understand that Net Neutrality is a contentious issue at best.
Because it is a contentious issue, we have invited a few outsider experts to provide commentary. Tomorrow we will have commentary from Prof. Christopher Yoo at Vanderbilt University Law School, and we plan to follow it up in the future with commentary from other Net Neutrality issue experts as their schedules may allow.
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Continue reading "Network Neutrality Debate: An Introduction and Discussion" »
Thursday, December 14, 2006
by Jeff Hicks
There's a number of reasons why a company would move to VoIP. Generally there's been some component of cost-savings - it may be in regular long distance savings, it may be in hardware cost savings (versus a PBX system), it may be that you only have one network infrastructure to deploy and manage.
But it's interesting how in the past couple of years, costs have become less of a factor in the decision process. Long-distance rates have dropped, so the cost factor is not quite as pronounced as it used to be, especially considering short-term rollout costs.
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Continue reading "VoIP Traffic Isn't Just Normal Traffic" »
Wednesday, October 18, 2006
Way back in 1995, Network World used the economic metaphor of inflation to report The Cost of Network Complexity. While 1995 might be considered the Paleozoic era of networking -- Windows NT was barely two years old -- and the technologies have since rapidly evolved, still the inflation metaphor holds up today.
"The cause of economic inflation is too many dollars chasing too few goods, diminishing the buying power of the dollar. In the case of network complexity inflation, we have too much network infrastructure being chased by too few network wizards. Net service quality (the currency provided by the support staff) declines because it is spread across too many service demands.
"When this occurs, there are two means of bringing service quality and service requirements back into balance: reduce the number of factors contributing to the complexity [NPD Editor's note: That's not going to happen.] ... or increase the size of the support staff to handle the increased complexity. [Nope, that's not happening either]"
Flash forward to today and it's clear that infrastructure tools have progressed over time, making enterprise networks more reliable in the process. However, increased reliability doesn't necessarily mean better performance and it doesn't necessarily mean a better experience for the end-user. Today users commonly expect a ubiquitous and instantaneous network. They want it now, anywhere at anytime.
Therefore, network engineers aren't getting much sleep!
Here are three big trends that have increased the volume and complexity of wide area network traffic, made monitoring application performance a necessity and sleep for network engineers a luxury:
Continue reading "Three Big Trends Affecting Network and Application Performance" »
