Mobile Backhaul

9.4 IP Sec VPN Deployment

9.4.1 Cell and Hub Site Solutions

When designing the VPN and choosing suitable implementation for the cell site, the network designer should take into account the unique requirements of the BTS site.

BTS's are located in a variety of places, indoor, outdoor on rooftops, inside or outside protecting cabinets, attached to building walls or at the antenna mast. They can also be subject to rain or high humidity, extreme temperatures, etc. Most of these site solution and environmental conditions present some challenges to the BTS and how to provide a suitable VPN solution.

Another factor that needs to be considered is the topology of the site, whether the site has only one BTS, multiple BTS's or other site support equipment share the same backhaul links.

Existing standalone SEGs for cell sites are based on small routing devices, with a capacity suitable for a few BTS's. These devices are not usually meant to withstand the outdoor weather conditions so they are only suitable for sites where there is at least a cabinet to shelter the equipment. They also possess enough physical ports and routing capabilities to act as site routers. So they are mostly to be found in bigger sites.

Management of the standalone SEGs can be either done using the appliance vendor specific system or it could be integrated with the overall transport network management system.

For smaller sites with only one BTS or for sites with reduced footprint, an integrated SEG solution could be ...