Bandwidth requirements for a basic audio stream

I signed up and started periodically using last.fm in Feb 2006. I stopped in August 2006 and didn’t go back to it just this past December. If you are wondering how I know that in such detail it has to do with how last.fm keeps a profile on you, but I’ll save that for another post. I have found that the selection of music it picks for me has greatly improved since I first signed up.

There are different encoding formats for video and audio that affect the bandwidth and timing requirements for the transmission of streaming content. Ignoring the technical details around this for now, if a end user decides to stream audio from a service such as last.fm, how much bandwidth do they require to listen to that single stream? To test this, I selected a track that was approximately 120 seconds in length and captured the audio stream while it played. The track played fine with no delays or problems. I captured the audio stream in two places, the laptop where the song was being played and on my service provider’s network at the demarcation point between my service provider and their upstream service provider. Capturing the same stream at two points allowed me to compare both captures for issues such as dropped packets or other anomalies or problems. My provider actually has two upstream providers, but a quick check of the BGP routing table showed all the data for last.fm coming from just one of the upstream providers.

Using simple math, if a service provider has 5000 subscribers and we assume that at peak 1% are listening to streaming audio in their home via one of the many services available on the Internet, that is a minimum rate of 7.85 Mb/s of bandwidth allocation the service provider must provide for the subscribers just listening to streaming audio. This does not include services such as web browsing, online gaming, watching video, downloading, or any other of the tasks that can be done over the internet. The demand to have more bits per second to the home is going to constantly increase.Whether  service providers are able to keep up with this demand is a subject of debate.