Chaining protocol

Whether operating as the primary or secondary half session, IMS sends both single and multiple RU chains. Half sessions can operate with either single or multiple RU chains as specified in the bind parameters.

IMS messages are usually sent and received as single SNA chains where only-in-chain (OIC) or first-in-chain (FIC) indicates beginning-of-message, and OIC or last-in-chain (LIC) indicates end-of-message. However, each page of an MFS-paged input or output message is sent or received as a single SNA chain. The beginning-of-message occurs when the first page is sent or received, and the end-of-message occurs at sync point (RQD2 or RQE2, CD) requested at the end of the last input or output page (except for MFS operator logical paging).

Optionally, end-of-message can be requested using LUSTATUS - commit immediately following the last page of MFS DPM-autopaged input.

Use the CANCEL command when errors are detected on multiple RU input chains.