This is more for the networking geeks out there, rather than your average iPhone user. Brough Turner, a veteran telecom guru and several-time CTO has got a theory. The short version is that AT&T has enough capacity to handle the massive amounts of traffic that the iPhone users consume, contrary to a lot of the news reports out there. The real problem is that AT&T has screwed up the configuration of their wireless network, he says.
The bottleneck link is the over-the-air link, i.e. the connection from radio access network or UTRAN to the Mobile Statation (MS) in the above diagram, therefore the critical buffers are those at the UTRAN. In practice the UTRAN includes both the basestations (called Node-Bs) and the Radio Network Controllers (RNCs) which coordinate handovers between basestations (among other things). Because of hand-overs, the amount of data buffered at the Node-B is relatively small. It’s the buffers at the RNC that must be large enough to deal with the delay variations in the radio network and yet small enough to induce packet loss when the network gets congested.
I have no idea if he’s right, but it makes sense. Good read, if you know networking.
