Shared BandwidthTuesday, June 24, 2008
I have written a lot about shared bandwidth as it applies to wireless, however, every connection from our house, business, coffee house, airport or hotel room is shared bandwidth at some point. If you use a cable modem at home, you share bandwidth with your neighbors and again as your information is being transported to and from the Internet. If you have a DSL connection and are paying for 3-MB service, your bandwidth is shared from the DSLAM (Digital Subscriber Line Access Multiplexer) back to the Internet. If you are using Wi-Fi in a public location, your bandwidth is shared with all of the others who are using that same access point. Further, the total amount of bandwidth is not dictated by the bandwidth available over the Wi-Fi connection, it is also affected by the wired connection that carries your data back and forth to the Internet. If the connection is a T1, the total amount of bandwidth is limited to 1.544 Mbps.
My focus has been on wireless bandwidth capacity issues, including the backhaul from a cell site to the packet switch that handles the traffic for a number of cell sites in a given area. Typically, each cell site is divided into three sectors, so the bandwidth over the radio channel is shared between users in the 120 degrees covered by that sector. However, the backhaul that moves the data back and forth between the cell site and the packet switch has to handle the data from all three sectors and then the packet switch needs to be able to aggregate all of the data from all of the cell sites controlled by the switch and move it back and forth to the network controller and on to the Internet. There can be bottlenecks all along this route: too much demand from a group of users; not enough backhaul from the cell site and/or from the switch to the network controller.
I have also pointed out that the only way to increase wireless capacity in a given area is to build cell sites closer together or to use pico, micro or femto cells to relieve some of the traffic on larger sites. But again, all of these solutions require bandwidth to move the data bits from one location to another, and in the case of building more sites, lead times come into play. In many parts of the country, it takes two or three years to develop, permit and build new cell sites.
The point is that it is not only the wireless industry that has to worry about bandwidth, data hogs and data capacity throughout their networks. The need for increased bandwidth starts within the Internet where demand has been growing by double digits every year. So far, the companies that provide the infrastructure have been able to keep up even though there is less and less of a financial payback for them to do so. We all know that the demand for bandwidth is insatiable-the more we get the more we want-and as IPTV, streaming videos and movie downloads become a common occurrence, the demand will continue to grow.
So wired and cable systems have to worry about broadband usage and broadband hogs as well. For example, Time Warner Cable is about to start charging users a fee for downloading more than a monthly limit, Comcast is talking about a limit of 250 GB of data per user per month and other cable companies are preparing to follow quickly on their heels. (While researching for this blog entry, I found several software programs that claim to "uncap" any bandwidth limits set by the cable companies. I guess no matter what the challenge, some hackers will set out to prove they are up it!)
What does all of this mean? Well, it means we will have to make several choices when it comes to our data consumption. The first is how fast a data speed we want. Most of us already made that decision when we subscribed to DSL or cable modem services. All of the pricing plans I have seen offer several different speeds at different price levels, and even Clearwire's wireless broadband offers several speed options. The next choice is how much data we want to use each month and how much we are willing to pay for it. For example, Verizon Wireless has gone from unlimited data (with some caveats) to two new plans: 50 MB per month for $39.95 and 5 GB per month for $59.95 with overage charges beyond those prices.
As the new systems are rolled out, a quality of service/data rate pricing model will emerge and those who want higher priority will pay more. And I believe we will see plans where we will be given a choice of downloading a large file during the day, which we will pay extra for, or we can wait until the early morning hours and have it sent to us for free.
So the trend to restrict the amount of data any one person uses in the course of an hour, a day or a month is not limited to wireless. Those who are saying that wireless data access should be just like wired data access (meaning all-you-can eat) are going to get their wish. Only it will be the reverse of what they wanted-data usage will be metered for wired as well as wireless systems to make sure overuse by a few does not disrupt the ability of the many to enjoy access to the services and applications they want and need.
By the way, this has nothing to do with net neutrality. Even with bandwidth restrictions in place, no Internet provider or service will have priority access to the bandwidth available to us. WE will choose what we do with it and how we use it.