scope:

SCOPE, PURPOSE, & APPLICATION

The Office of the Manager, National Communications System (OMNCS), tasked by directives from the White House to ensure that a survivable and enduring National Security and Emergency Preparedness (NS/EP) telecommunications capability is available during national emergencies has endorsed the development and adoption of a standard to support increased call completion capabilities for critical users. The High Probability of Completion (HPC) network capability would be applied during the call setup of NS/EP calls by providing for an identifier for those calls in the SS7 network protocol. This identifier would allow NS/EP calls to be recognized as they are transported across and between networks so that call completion improvement techniques could be applied by service providers to increase the probability of completion during periods of network congestion or damage.

The techniques used by service providers to enhance call completions in the network might vary from the application of special network management controls, to the enablement of special routing or queuing mechanisms, to partitioning and prioritizing completion of NS/EP calls. This standard does not describe any of these special routing or handling procedures, nor does it describe the manner in which the user originating the call would indicate to the network the need to have the call so marked. These may be the subject of future American National Standards or may be provided by non-standardized procedures based on agreements between network providers, service providers, or users.

The capability described in this standard includes two essential portions:

♦ A special indicator carried through the network with the call set-up signaling to identify the call as an NS/EP call;

♦ Special marking of each set-up message by each network exchange to increase the probability of it being transferred to the next exchange in the case of congestion in the signaling network.

This standard only describes the transfer of the indicator through an ISDN and the signaling interworking with non-ISDNs. This network capability may be utilized by standardized or nonstandardized services accessible to either ISDN or non-ISDN subscribers.