Short Message Services have proved to be one of the major successes over the past few years in mobile telecommunication. A significant part of most mobile operators’ recent revenues come from these services.
Far from being a short-lived trend, Short Message Services provide a real added value, and have convinced mobile customers to adopt new usages of their mobile phones.

This success has led mobile operators to consider their short message capacity as highly critical, especially since short message centres often provide a public interface.

Major operators’ concerns, in order not to jeopardize this major source of revenue, include:

	requesting an extremely high level of quality on short message services
	ensuring continuous customer access to the service, preventing denial of service attacks
	protecting customers’ privacy against unsolicited or offensive calls, mobile phones being considered by customers as much more personal than any other devices.

Cellicium's SMS Firewall platform is to be installed between the operator's SMSC infrastructure, and external third parties. The SMS Firewall handles connections between ESMEs and the operator's network. Messages exchanged in either direction go through the set of application filters before being passed on to the initial destination, blocked or acknowledged.

SMS FIREWALL Platform

Cellicium’s SMS Firewall is a carrier-grade platform providing a security layer on top of existing short message service infrastructures.

It was designed according to an industry standard architecture. The clear separation between the lower layers and the application level processing is the key to the level of flexibility operators need to counter those new threats.

The robust and efficient base framework handles:

	low level network interconnections
	protocol coding and decoding
	session management
	user profiles
	operation and maintenance.

Application filters

Application filters can benefit from this framework to implement high level features, such as:

	resource management, in order to guarantee efficient resource sharing between all clients
	MSISDN aliasing, to protect mobile customers against spamming or offensive content
	flooding detection, so that such denial of service attacks can be first identified, then cured
	selective barring of messages.

This versatility includes the ability to include new filters, possibly developed to meet operator’s specific needs, to be executed either during the call establishment procedure, or during the call handling.