Graves On SOHO VoIP

Do you ever wonder what factors impact your experience using VoIP technology? Very recently Celideo, a maker of testing tools for voice and video over IP, posted a very nice summary of the issues surrounding VoIP quality. The post is entitled, “VoIP QoS Metrics Explained” and I find it a good tutorial on the subject. It’s comprehensive yet concise, and given in easy-to-understand terms.

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Earlier this week I found a newly launched VoIP QoS monitoring service called VoIP Spear. It works by sending a ping to the end-point in question at a certain interval, then analyzing the timing of the resulting responses. The service is free for monitoring a single end-point so I setup an account and pointed it at my office IP address.

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My screencast guide to traffic shaping for VOIP using m0n0wall has been posted on the m0n0wall web site.

However, Manuel Kasper (m0n0wall project lead) had some interesting ideas on how to revise and perhaps simplify my approach. What he describes departs from the approach underlying the present implementation of the Magic Shaper in m0n0wall. Use of the Magic Shaper is the basis of the existing screencast.

Updated to provide a YouTube version in the post and ftp downloadable high quality version.

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Brough Turner has written an updated version of his classic opinion/overview of network QoS. His opinion that we’ll never have end-to-end QoS on the internet raised some eyebrows in December 2006…but he was dead right, and remains so to this day.

The updated version includes some new information about potential business opportunities for farsighted ISPs who might offer a better class of service through ensured QoS.

Not to give away the punchline, but here’s his summary:

There is no Internet QoS today, and it’s unlikely any complex QoS scheme will ever be added to the Internet as a whole. To the extent next generation networks with rich QoS are deployed, it will only be within walled gardens. But there may be opportunities for ISPs to create a simple premium service that could generate incremental revenue.

It’s a good read, not too technical and with references from good solid sources.

My own posts about small network QoS and traffic shaping have been the most popular posts since I started writing this blog. There appears to be real hunger for information about this stuff. Brough gives us a definitive overview of the subject.

Many thanks!

My series called The Beginners Guide To Sucessful VOIP Over DSL was just republished over at Small Net Builder. Tim Higgins, the editor over there, has been very supportive of my recent efforts. Where they are interested I may be blogging about some of my projects on their site as well as here on my own.

Jared Valentine has posted an interesting description of a system he developed for automatically manipulating QoS & bandwidth allocation to support the use of VOIP over his DSL service. He calls this “Application Aware Triggered QoS.”

He described his initial problem as being trouble with inbound bandwidth management. This is something that I’ve never experienced myself. My trouble was always related to limited outbound bandwidth.

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I just love it when things work as expected. Having been out of town for a couple of days I came back today and needed upload quite a few things to servers in the UK. As I was doing this the phone started to get busier. That implies that the VOIP systems are functional. Nice.

The fact that the call quality is really good tells me that my QoS and traffic shaping solution is working well. I had pinned my ADSL service with both upload (FTP) and download (syncing Outlook email) and the voip call quality was still excellent.

It’s kind of fun to watch m0n0mon graph my DSL traffic, and note when a call ends by the sudden change in data rate. This is clearly indicated by the drop in data flow noted on the left side of the m0n0mon image.

I must admit that I’m more than a little surprised a what people read around here. The single most popular article is the one I wrote back in January 2006 about Building An Embedded Asterisk Server Using Astlinux On a Soekris Net4801. I would have thought that would have less appeal since it was published elsewhere over two years ago.

The next most popular articles are the series called A Beginners Guide To Successful VOIP Over DSL, most especially the posts on QoS and traffic shaping. People come by and read these things every day.

Hardware reviews are something that I’ve done many times over the years. Although deep in my past they were not technology related. These I will be doing again beginning with the Snom M3s. I need to be disciplined about using the phones for long enough to really learn about them in depth, and not just go with my first impressions. Even though the phones are in daily use the review will is a few weeks away.

Amongst my next topics I think I’ll be trying a SIP-to-GSM gateway. I’d like to provide my own 911 and 411 service by bridging calls over to my cellular account.

If you’ve got any ideas for topics or items for review let me know. I’m always open to suggestions.