Contention Ratios

A network’s contention ratio refers to the ratio of subscribed bandwidth to the actual available bandwidth.

For example, if a wireless system had 10 Mbps of available capacity and four 10 Mbps customers were connected, then the network would be operating at a contention ratio of 4:1.

The reasoning behind the oversubscription approach is that not all customers will be using the bandwidth simultaneously, and more cost effective pricing can be delivered by sharing the available bandwidth.

This methodology is commonplace in Service provider networks. Typical business networks will operate at up to a 10:1 contention, while consumer level services such as ADSL will operate at 50:1 and sometimes even 100:1 contention levels.

The Unwired business network provides 4:1 contention for its contended services.

The contention ratios provided by the Unwired access network are dependent on the type of service being delivered. For services delivered under 10 Mbps and utilising fixed WiMAX technology the contention ratio is set at 4:1. This is controlled at the wireless base station.

The aggregation and core networks are totally un-contended and are dimensioned such that congestion does not occur. Services above 10 Mbps are un-contended at the access point as well as in the core.

Unwired’s philosophy is to provide additional capacity in the aggregation and core networks when traffic levels reach 80% of maximum available throughput for a given link whether it is fibre or wireless backhaul, hence aggregation and core links operate contention free.