Lucent Technologies 555-661-150 manual Overview

MERLIN LEGEND Communications System Release 6.1	Issue 1
Network Reference 555-661-150	August 1998

4Security

Overview		Page 4-2
Overview	4

Security planning and implementation, like other aspects of networking, require careful coordination among system managers. Local system business needs must be balanced with overall routing and security considerations. Network system managers must combine existing features and new networking features to safeguard against toll fraud. At the same time, security features must be fine- tuned to enable efficient calling across the network.

As discussed in earlier chapters, ARS and Remote Access features are used in combination to allow users to access PSTN trunks connected to other systems in the network. Such ARS calls are made normally, just as they are in non- networked systems. System programming of ARS tables, routes for tandem trunks, and remote access default class-of-restriction (COR) ensures correct and secure call routing. For the purposes of security, Facility Restriction Levels (FRLs) are the most important components of these features. The next topic in this chapter discusses how different types of FRLs—ARS, remote access default COR, and extension—interact in a private network.

NOTE:

The ARS access code of a networked system should never be assigned to the non-local dial plan. This might allow network users to inadvertently or purposefully access PSTN facilities connected to a network system. The local system ARS access code cannot be programmed into the non-local dial plan; if all ARS access codes in a network match, this safeguard is more effective. For this reason and for convenience and proper call-routing in some situations, it is recommended that all the systems in a network use the same ARS access code.

To enable calling among users on a network, certain calling restrictions are suspended when people on one system call extensions on another system, while others remain in effect. In addition, private network trunks and pools of private network trunks must be safeguarded and treated differently than PSTN trunks in order to avoid toll fraud through access to other networked systems. Table 4–1 summarizes these operations. The Suspended column relates to restrictions only and indicates whether or not the restriction is applied to calls made to non-local extensions.

“Facility Restriction Levels and Remote Access” on page 5 discusses security considerations that require more detailed information.