It's Only Fair: Telcos manage IP traffic to dictate fair usage

The network may not be seeing many areas of investment these days, but service providers have shown strong interest in a least one aspect: deploying smart boxes at the edge to process the packets carrying data and voice traffic over emerging IP networks.

The main force driving such deployments today — which include elements such as deep packet inspection (DPI) boxes, policy servers and customer record look-up databases, among others — is the requirement to more actively track and manage bandwidth consumption. Requests for help in deploying so-called “fair usage” applications — named as such in a nod to Net neutrality concerns — are flooding into vendors in these areas, and the first announced deployments have generated high-profile attention, wanted or not. Behind the scenes, vendors and analysts say, fair usage apps are being deployed quietly by almost every wireline, and increasingly wireless, carrier.

The challenge is that the questions are not only technology-driven, but are affected by business and even public policy concerns as well.

“I think there's no question all operators — telcos and cable [multiple system operators] — are moving to some type of usage control or tiered service offering based on monthly usage,” said Jeff Heynen, analyst with Infonetics Research. “Although operators have many tools at their disposal to increase bandwidth to each subscriber, I think they all feel it's the best time to culturally get people used to the fact that they have to manage how much bandwidth they use per month.”

It's instructive to look at some of the first public implementations of fair usage. The most closely watched is by Comcast, which in its latest bandwidth management deployment is taking what it calls a “protocol-agnostic” approach. To that end, the system does not examine which protocols or applications are consuming bandwidth. Rather, it examines which individual users are consuming excess bandwidth (defined as more than 70% of the subscriber's provisioned service level — i.e., the service level they are paying for) for a specific period of time, which Comcast measures in 15-minute increments. In essence, if a portion of its network reaches a congestion level, Comcast limits its heaviest users for a short period of time until that congestion goes away.

Three edge boxes factor in the deployment: an IP detail record (IPDR) server that collects usage information from the cable modem termination system (CMTS) in the Comcast network to track how many bytes a subscriber is consuming. (Comcast has yet to publicly name its IPDR vendor.) A second server from vendor Sandvine uses the Simple Network Management Protocol (SNMP) to measure CMTS port usage and detect when a port is nearing a congestion state. When that happens, the Sandvine server asks the IPDR server for a list of users over their allowed consumption state, and if there are any (there may not be), it notifies a policy server from vendor Camiant.