Mobile Capacity Management – Don’t Forget OTN, SDH, SONET and IP/MPLS

Posted on: 29th February 2012

One of our “Seven Best Practices for Successful Mobile Network Planning” discusses how large mobile networks now have backhaul and transmission capacity issues as complex as many fixed-line service providers.

Previously, mobile service providers simply had to purchase a few E1/T1 leased lines and microwave links for backhaul, and only marginally larger capacities for core transmission. Today, a new 4G cell site may require 100Mbps or even 1Gbps backhaul link. There’s also far more sites to connect as 2G, 3G and 4G are layered on top of each other, and pico/femto-cells fill in urban coverage.

Backhaul transmission may now comprise:

• A mix of legacy E1/T1 and high-capacity Ethernet leased lines

• Point-to-point and ring microwave links

• Aggregation on to SDH/SONET, IP and MPLS

• Optical (OTN, DWDM) fibre runs connecting high-demand points

Not only do planners have a choice of technology, they now also need to manage capacity across network layers.

Capacity must first be planned at the logical layer, forecasting IUB, IUR, IUCS, etc. traffic and signalling loads. This traffic may be carried by a combination of Ethernet and IP/MPLS, which in turn is carried by SDH/SONET, PDH microwave and OTN/DWDM.

Capacity management demands that at all stages in the planning lifecycle the dependencies between these layers are considered. Consequential demands on lower layers may require additional planning tasks and, when considering both quality and resilience, there is a need to be aware of the lower layers when optimising traffic routes.

Automation is the best way to achieve multi-layer capacity management. Build planning sizes the service layer based on growth forecasts, determines where capacity upgrades are necessary, and then automatically creates a build plan for the transmission layer(s). This ensures that transmission planners are as much driven by market forecasts as they are by historic utilisation trends, and also enforces planning policy across all network layers.