21. SCTP message type Message Name Description DATA The payload user data INIT This chunk is used to initiate a SCTP association between two endpoints. INIT ACK The INIT ACK chunk is used to acknowledge the initiation of an SCTP association. SACK This chunk is sent to the peer endpoint to acknowledge received DATA chunks and to inform the peer endpoint of gaps in the received subsequences of DATA chunks. HEARTBEAT An endpoint should send this chunk to its peer endpoint to probe the reachability of a particular destination transport address defined in the present association. HEARTBEAT ACK An endpoint should send this chunk to its peer endpoint as a response to a HEARTBEAT chunk. ABORT The ABORT chunk is sent to the peer of an association to close the association. SHUTDOWN An endpoint in an association MUST use this chunk to initiate a graceful close of the association with its peer. SHUTDOWN ACK This chunk MUST be used to acknowledge the receipt of the SHUTDOWN chunk at the completion of the shutdown process. ERROR An endpoint sends this chunk to its peer endpoint to notify it of certain error conditions. COOKIE ECHO This chunk is used only during the initialization of an association. It is sent by the initiator of an association to its peer to complete the initialization process. COOKIE ACK It is used to acknowledge the receipt of a COOKIE ECHO chunk. SHUTDOWN COMPLETE This chunk is used to acknowledge the receipt of the SHUTDOWN ACK chunk at the completion of the shutdown process
SIGTRAN stack is the protocol stack that supports transmission of Switched Circuit Network (SCN) signaling via IP network. This protocol stack supports the inter-layer standard primitive interface defined in SCN signaling protocol hierarchy model, so as to ensure utilization of the existing SCN signaling application without modification. It also uses the standard IP transport protocol as the transmission bottom layer, and satisfies the special transmission requirements of SCN signaling via adding its own functions.
An association is the logic relationship, or channel, established between two SCTP endpoints for data transmission, via the four-way handshake mechanism prescribed in SCTP. SCTP is characterized by Stream. In an SCTP association, stream is a uni-directional logic channel established from one endpoint to the other associated endpoint. The data to be delivered in sequence has to be conveyed within a stream. Association and stream
AS A logical entity serving a specific Routing Key. An example of an Application Server is a virtual switch element handling all call processing for a unique range of PSTN trunks, identified by an SS7 SIO/DPC/OPC/CIC_range.