New Peak Load Issues for Mobile

There's only one problem worse than dealing with peak load, and that is average load that starts to look like peak load. In the voice world, peak load has been the bigger issue, not average load.
Data networks have peak load issues as well, but those issues are mostly about the number of bits to pushed through the pipe, not generally use of circuits or network elements or ports.

Wireless is starting to have other problems, though, as data usage grows. And you instinctively would think bandwidth has to be the issue. It isn't. But take the easy stuff first.

Just as there are two “rush hours” on the road (6 a.m. to 9 a.m. and 5 p.m. to 7 p.m.), enterprises typically experience two “rush hours” on their phone systems, says Art Yonemoto, owner of his own telecom expense auditing firm. For most enterprises those PBX rush hours happen at mid morning (10 a.m.) and early afternoon (2 p.m.). Hospitals, though, tend to have one of their busiest hours at 9 a.m., especially on Mondays, as their patients call to schedule appointments.

For the most part, though, enterprises handle their phone system peak loads quite well. Mobile networks cannot say the same. as they generally are designed to handle about 80 to 90 percent of calls on a non-blocking basis. At peak hours, blocking occurs.

Some calls simply go straight to your voice mail. The other obvious issue is a dropped call, which happens because you are moving from one area to the next, and the next cell tower has no free radio assets to hand off the call.

But there are other problems emerging, and that is amount of data traffic, and the different characteristics data applications impose on the network. Bandwidth alone is not the entire problem, any more than bandwidth is really the problem for voice traffic.

The issue is that radio resources are tied up even when not that much bandwidth is flowing over the radio network. An obvious example is a mobile virtual private network client, which essentially nails up a connection even when actual data is not flowing. The issue then is the strain on radio resources, not bandwidth as such. Other applications that don't actually consume much bandwidth might have lots of signaling and pinging. Some social networking applications and even mobile email devices can create that sort of stress.

So for wireless networks, it now appears application interactivity--not just bandwidth--is becoming a gating issue. It is an issue bandwidth alone does not fix. The additional new issue is occupation of radio resources.