Peercasting

I talked with Michael King, President of Abacast - an internet streaming company that provides a hybrid solution - standard server-to-client and bandwidth efficient peer-to-peer streaming. It was started by a group of radio owners and tech people who were looking for a broadcasting technology that had an economy of scale. As I have described, for online streaming, each additional listener creates an added cost - unlike terrestrial broadcasting - which costs the same whether 2 or 2 million people are listening.

Abacast uses peer-to-peer technology to reduce the cost and bandwidth impact each additional listener has on a streaming station. You can view their website for a mroe detailed explanation, but basically - when a listener arrives at a station's listening page, they are provided with options - they can listen to the stream normally at a lower bandwidth, or they can download a plugin from Abacast. If they choose to download the plugin, which 70% of users do, they get a higher bandwidth, higher quality, more stable stream. Normally, web users are reluctant to downlaod plugins and software, but when it comes from a trusted site, like that of a radio station, and there is an obvious payoff - better audio - they warm up to the idea.

The plugin is what makes the peer-to-peer benefits happen. Instead of downloading all of the audio stream from the station server, the plugin gets the audio from other listeners. Because internet traffic is packet based and there is no guaranteed quality of service, audio streams have to build up a buffer. This buffer fills up with 30 or so seconds of audio before it starts playing (that's what happening when you see "buffering" while you are waiting for your audio stream to start). This way, if the connection gets dropped or packets get lost, your audio player can ask for them a second time. If they get there before the 30 seconds run out - you'll never even know there was a problem.

The plugin takes advantage of this buffer. You see, the listeners often have a lot of unused bandwidth on their internet connections. The plugin takes the audio in the buffer and makes it available to other listeners. So listener #1 will get all of his audio from the server, but listener #2 can get all of her audio from listener #1, if he has enough bandwidth. The more listeners you have, the more options your listeners have to get their audio from. King says that they can reduce bandwidth usage from the server by up to 90%. That is a massive savings.

The other advantage is that because listeners can get their buffer filled from many sources, unlike the one source that regular streaming provides, Abacast's plugin is more stable and reliable. This leads to less audio break-ups and lost connections and less frustrated listeners - which creates the words programmers want to hear - increased TSL. Abacast has found that listening times increase for listeners with the plugin installed.

The final bonus with this technology is that it is corporate friendly. Some corporations don't let workers listen to online audio streams at work, not because they don't want people listening to the radio, but because it taxes their bandwidth - just like I described. They have to carry the same duplicate stream for every listener in their network. With Abacast, only one person has to get the audio from the outside network, and then all of the other listeners can pull it from that first listener - freeing up the limited connection to the internet, and utilizing the abundant bandwidth on the internal network.