QSIG Services In Packet-Based
Multi-Media Communication Systems

Standards for QSIG have already done the work of adapting public ISDN supplementary services for peer-to-peer networking. For this reason QSIG supplementary services have been adopted as the basis for supplementary services in packet-based multi-media communication systems -- so called "H.323 terminals" -- by ITU-T.

H.323 version 1 did not include any supplementary services.

Several Recommendations on supplementary services were produced as part of H.323 version 2 in 1998. These are:

• Recommendation H.450.1: "Generic functional protocol for the support of supplementary services in H.323"
• Recommendation H.450.2: "Call Transfer supplementary service for H.323"
• Recommendation H.450.3: "Call Diversion supplementary service for H.323"

Several more supplementary services have been published since then in parallel with versions 3 and 4 of H.323. These are:

• Call Hold (Recommendation H.450.4)
• Park and Pickup (Recommendation H.450.5)
• Call Waiting (Recommendation H.450.6)
• Message Waiting Indication (Recommendation H.450.7)
• Name Identification (Recommendation H.450.8)
• Call Completion (Busy, No reply) (Recommendation H.450.9)

Work is presently in progress for the following supplementary services:

• Common Information

ECMA has recently completed technical work on draft ECMA Standards dealing with interworking between QSIG and H.323 systems for the first group of these supplementary services; namely for:

• mapping between elements / procedures of the QSIG Generic Functional Protocol and elements / procedures of the Generic Functional Protocol (H.450.1) specified for the H.323 environment.
• mapping between elements / procedures of the QSIG Call Diversion (ECMA-174) and Call Transfer (ECMA-178) supplementary services and elements / procedures the equivalent supplementary services (H.450.3 and H.450.2 respectively) specified for the H.323 environment.

These ECMA Standards are expected to be published in mid-2000.

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