Bellsouth provided some estimates of bandwidth costs in the future as video on demand and high-definition video becomes more common on the network. "Internet" traffic is a very small part of the future bandwidth requirements. Voice/VOIP is completely lost in the noise.
This is a bit of a mental exercise because it assumes everything will be unicast across the backbone. In reality, no one is designing their networks that way (not cable, ilec, clec, wireless, etc).
Todays average residential broadband user consumes about 2 gigbytes of data per month, Kafka estimated, which costs the service provider about $1. As downloading feature films becomes more popular, they might consume an average of 9 gigabytes per month, costing carriers $4.50.
The average IPTV user will likely consume about 224 gigabytes per month, he added, at a monthly cost to carriers of $112, a giant leap from the less than $5 attributed to Internet use. If that content were high-definition video, the average user would be consuming more than 1 terabyte per month at a cost to carriers of $560 per month.