Asymmetric Satellite Backhaul


Asymmetric Satellite Backhaul

Asymmetric Satellite Backhaul

The deregulation of the satellite internet provision market in the developing world, has created a need for the cost effective delivery of Internet services. Internet traffic is normally highly asymmetric having a typical 4:1 ratio of incoming to outgoing traffic. The user send a simple web page request and in response the server downloads the page, graphic images, scripts etc. Satellite capacity is provisioned on a uni-directional basis with charges per Mbps of bandwidth required. So there are considerable potential cost savings through minimising the satellite capacity and matching the terrestrial infrastructure to it.

Typical applications are for the provision of Internet trunk links with E3 / E2 transmission rates (e.g. 34/8 Mbps operation).

Another issue is that the main internet exchange centres tend to be located some distance from these earth station, hence the requirement to backhaul the connection over a leased line.

Historically satellite applications were matched to the bandwidths available terrestrially, but this is extremely inefficient. Alternatively routers were used to perform this speed translation function, but these routers then partitioned the ISPs network and caused operational problems, especially where network updates were required.

The above application shows how a Metrodata Access Processor (AP) product can be used to support the exact satellite data rates required and backhaul this data over a terrestrial leased line. A variety of different satellite modem interfaces can be supported: e.g. EIA530, HSSI, ECL or ASI, and these can be backhauled over a variety of leased line services: e.g. E3, DS3 or STM-1/OC-3. This solution also properly resolves the complex clocking issues that often occur when implementing and integrating satellite and terrestrial infrastructures.

The unique features of the AP Access Processor family of products allow major cost savings in satellite/terrestrial systems integration.

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