Protocol Basics: What is a Telecom Gateway?

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Gateway may be the most overused term in all of communications.  It designates a wide variety of systems and/or functions that enable communications between two parties that cannot be connected in a direct way either for technical, management or administrative reasons. The parties in question can be a host system and a network, two networks or two elements in the same network.

In gateways that inter connect equipment operating incompatible protocols, the main value of the gateway is to make communication possible by inter working the protocols. This means having the gateway performing all functions that are necessary to have each party communicating with the other using its own set of protocols in a transparent way.

Frequently this interworking is performed by running in parallel the protocol stacks required to communicate with each party and having an interworking function that specifically makes coordination and conversion between two protocols only.

The decision on which level or protocol layer is the best to perform inter working is either defined in relevant standards or left to implementation. How the interworking is implemented can also vary widely. This can lead one to understand that interworking is simply an additional layer that would bridge or control the protocols and rely above both protocols to interwork.  And interworking sometimes does not mean protocol conversion but it can also deal with the upper protocol elements relay.  Indeed protocol interworking can cover a wide range of functions.

Handling of protocol interworking in gateways or other network elements is complex and difficult even if standardization has now emerged that specifies such functions. When real protocol conversion is required a great deal of attention must be paid to call state transparency and to administration functions to implement a flexible and suitable solution. But in any case interworking has to deal with operation and administration constraints related to configuration, charging and security that impacts interworking implementation.

To learn more about Protocol Interworking download this white paper.