General

This part of ISO/IEC ISP 15125 defines a set of DISP capabilities and constraints which a DSA implementation may support over ROSE. These capabilities and constraints cover the following areas:

• shadow supplier and consumer roles
• primary and secondary shadowing
• association initiator and responder functions
• all DISP operations
• error handling and recovery

The objective of this part of ISO/IEC ISP 15125 is therefore to define a level of DISP capability such that conforming DSA implementations shall be capable of establishing and maintaining DISP associations over ROSE together in a consistent manner.

ISO/IEC ISP 15125-11 defines the level of DISP capability which a DSA implementation may support over the Reliable Transport Service Element (RTSE).

This part of ISO/IEC ISP 15125 does not specify any requirements related to the administrative, management or functional capabilities associated with shadowed information transferred using DISP. Those aspects are covered by ISO/IEC ISP 15125-14 (ADY62 - Establishment and Utilisation of Shadowing Agreements) and ISO/IEC ISP 15125-12 (ADY53 - Shadowing Subsets).

Position within the taxonomy

This part of ISO/IEC ISP 15125 is identified in ISO/IEC TR 10000-2 as ADY51 “The Directory - Shadowing Capabilities - Shadowing using ROSE”.

Scenario

In the Directory, replication of information between DSAs can be achieved by use of the standardized shadowing mechanism defined in ISO/IEC 9594-9: 1995 | ITU-T X.525: 1993 using DISP (see Figure 1).

A shadowing agreement must be established between two DSAs and the role of each of the DSAs identified, that is which DSA is to operate as the shadow supplier and which as the shadow consumer.

A single DSA may operate as a shadow supplier in some agreements and as a shadow consumer in other agreements.

Primary shadowing occurs when a DSA supplies information mastered by that DSA to a shadowing DSA.

Secondary shadowing occurs when a DSA supplies shadowed information on to a shadowing DSA.

The transfer of information being shadowed (either primary or secondary) between supplier and consumer DSAs is achieved by use of DISP, which may operate over either ROSE or RTSE. This part of ISO/IEC ISP 15125 relates to DISP when operating over ROSE.

DISP is specified in ISO/IEC 9594-5: 1995 | ITU-T X.519: 1993.