1.4.1 MS Applications That Only Send Data

This most simple type of application only sends data and never receives any data from the SNAP-IX node. This type of application can use either the synchronous or asynchronous entry point and needs to use only one or both of the following verbs to send data:

• The SEND_MDS_MU verb sends data in MDS_MU format, which SNAP-IX sends to a remote MS application.

• The TRANSFER_MS_DATA verb sends data in NMVT format, which SNAP-IX sends to a remote MS application. The data can be either a complete NMVT or subvectors to which SNAP-IX adds the required NMVT header information.

For more information about the synchronous and asynchronous entry points, see Description of the MS API Entry Points.

1.4.2 MS Applications That Both Send and Receive Data

This type of application both sends data and receives data and status indications from the SNAP-IX node. When you write this type of application, you must include the following verbs (except where noted, you can use either the synchronous or asynchronous entry point):

1. Issue a CONNECT_MS_NODE verb to establish communication with the SNAP-IX node, so that the application can register to receive data, focal point indications, or both.

2. Register with the SNAP-IX node to indicate the type of data that the application wants to receive. You must use the asynchronous entry point to register with SNAP-IX using either or both of the following verbs:

   • The REGISTER_MS_APPLICATION verb registers the application with SNAP-IX as an MDS-level application that can accept MDS_MUs. An option on the verb enables the application to request information about the focal point for a particular MS category. SNAP-IX uses the MDS_MU_RECEIVED indication, the FP_NOTIFICATION indication, or both, to pass the required data to the application.

   • The REGISTER_NMVT_APPLICATION verb registers the application with SNAP-IX in one of the following ways:

     • As an NMVT-level application that accepts NMVTs with a particular MS major vector key. SNAP-IX then uses the NMVT_RECEIVED indication to pass NMVTs to the application.

     • As an MDS-level application that accepts NMVTs with a particular MS major vector key after they have been converted to MDS_MUs. SNAP-IX converts the received NMVTs to MDS_MUs and uses the MDS_MU_RECEIVED indication to pass the MDS_MUs to the application. This usage allows an MDS-level application to receive NMVT-level data and status indications without having to understand NMVT-level data formats.

     When the application registers with SNAP-IX, it supplies the address of a callback routine. SNAP-IX calls this callback routine when data of the requested type arrives at the node. For more information about the data structures that SNAP-IX supplies to the callback routine, see Management Services Indications.

3. After registering itself, the application can do any of the following:

   • Send data to the SNAP-IX node using either or both of the following verbs:

     • The SEND_MDS_MU verb supplies data in MDS_MU format, which SNAP-IX sends to a remote MS application.

     • The TRANSFER_MS_DATA verb supplies data in NMVT format, which SNAP-IX sends to a remote MS application. The data can be either a complete NMVT or subvectors to which SNAP-IX adds the required NMVT header information.

   • Receive status information from the SNAP-IX node when SNAP-IX returns the following status indications:

     • The FP_NOTIFICATION indication provides information about the focal point for a particular MS category. SNAP-IX returns this indication to an MDS-level application that has registered to receive focal point information.

     • The MS_STATUS indication informs the application of changes in the status of the SNAP-IX system (when the application's communications path to its connected node has been lost, or when the SNAP-IX software has stopped). SNAP-IX returns this indication to both MDS-level and NMVT-level applications.

   • Receive data from the SNAP-IX node when SNAP-IX returns the following received data indications:

     • The MDS_MU_RECEIVED data indication returns an MDS_MU to an MDS-level application. The returned MDS_MU is one of the following:

       • The MDS_MU sent by a remote application if the MS application registered using REGISTER_MS_APPLICATION verb

       • An MDS_MU converted from an incoming NMVT if the MS application registered using the REGISTER_NMVT_APPLICATION verb

     • The NMVT_RECEIVED data indication returns an NMVT to an NMVT-level application that has registered to receive NMVTs.

4. When the application completes, it must end its registration with SNAP-IX by issuing one of the following verbs:

   • The UNREGISTER_MS_APPLICATION verb ends the application's registration with SNAP-IX. After the application issues this call, SNAP-IX no longer sends MDS_MUs to the application.

   • The UNREGISTER_NMVT_APPLICATION verb ends the application's registration with SNAP-IX so that it no longer accepts NMVTs with a particular MS major vector key.

5. After the application ends its registration with SNAP-IX, it must issue a DISCONNECT_MS_NODE verb to end communication with the SNAP-IX node and free the resources associated with the application.

For more information about the synchronous and asynchronous entry points, see Description of the MS API Entry Points.