MERLIN LEGEND Communications System Release 6.1 | Issue 1 |
Network Reference 555-661-150 | August 1998 |
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2Call-Handling Scenarios
Networking Guidelines | Page 2-9 |
SYS PROGRAM➙LINES/TRUNK➙REMOTE ACCESS➙NONTIE/TIELINES➙
RESTRICTIONS
When programming the default COR, change the Calling Restriction option to unrestricted (the factory setting is outward restricted). You should assign Disallowed List 7 to include; 900, 976, and other types of calls that users should not be allowed to call. When a call is received at a non-local system that routes it to another private network system, the FRL assigned to the default COR is compared to the local UDP or ARS route FRL to permit or forbid the routing of the call. For a call to go through, the route FRL must be equal to or less than the default COR FRL. These considerations are discussed in detail in Chapter 4, “Security.”
To make it easier for users working away from their home system in a private network and for maintenance and toll-saving purposes, you can include non-local systems’ Remote Access codes in your non-local dial plan. Each networked system should have a unique, unambiguous Remote Access code. These numbers must not conflict with extension ranges in the networked systems’ non- local dial plans. Calls to the remote access extension that require barrier codes use the COR assigned to the barrier code entered.
!SECURITYlALERT:
Networked systems require special attention to security issues. Follow the rules below when setting up and planning your system for private network use.
■Ensure that barrier codes are required for incoming remote access calls received on PSTN dial-plan routed and tandem facilities that route to the Remote Access code (889, for example). When you program the default COR, turn the barrier code requirement on. This setting is ignored for ARS calls and calls to non-local extensions across the private network. However, it is still applied to DID and PRI dial-plan routed remote access calls as well as to calls received on a tandem trunk and routed to a Remote Access code. Because the COR Calling Restriction must be set to unrestricted for private network calling, using barrier codes on these facilities is essential in order to apply security measures. When a Remote Access code is included in the non-local dial plan of the calling system, the caller’s barrier code FRL on the called system is compared to the UDP or ARS route FRL on the called system. See the Feature Reference and “Remote Access Default Class-of-Restriction Settings” on page 6 for details.
■Extension and ARS FRLs should be carefully and stringently assigned in order to prevent unauthorized trunk-to-trunk transfers to local PSTN facilities. Table 4–1, page 4-3 explains the operation of this feature in a networked system.
