Unidirectional streams within an association. As shown in the above figure, SCTP allows multiple SCTP supports multiple logical streams to improve data Multiplexed flows do not block one another.Ī stream can be thought of as a sub-layer between the transport layerĪnd the upper layer. Head-of-the-line blocking problem of TCP. The multiple stream mechanism is designed to solve the The initiating endpointĬoncludes the graceful close with an SCTP packet that contains a SHUTDOWN With an SCTP packet containing a SHUTDOWN ACK chunk. SCTP packet that contains a SHUTDOWN chunk. Receipt, and confirms availability, with an SCTP packet containing a HEARBEATĮither SCTP endpoint can initiate a graceful association close with an SCTP monitors endpoint reachability by periodically sending SCTP The recipient endpoint acknowledges with an SCTP packet containing a SACK Send unidirectional data streams using SCTP packets that contain DATA chunks. Once an association is successfully established, an SCTP endpoint can The association, as well as the maximum inbound streams accepted from the otherĪssociation establishment is completed by a COOKIE ECHO/COOKIE ACKĮxchange that specifies a cookie value used in all subsequent DATA exchanges. (issued by the responder) specify the number of outbound streams supported by ThisĬhunk can also include one or more IP addresses at used by the respondingīoth the INIT chuck (issued by the initiator) and INIT ACK chunk SCTP association with an SCTP packet that contains an INIT_ACK chunk. Endpoint2 acknowledges the initiation of an Packet that contains an INIT chunk, which can include one or more IP addresses Release, the IP address portion of an SCTP Transport Address must be aĪn SCTP transport address binds to a single SCTP endpoint.Įndpoint1 initiates the association by sending Endpoint2 an SCTP Is the combination of an SCTP port and an IP address. SCTP makes no correlation between an inbound and outbound SCTP distinguishes different streams of messages within one Is a unidirectional logical channel established between two associated For retransmissions however, another active path may Is the default destination source address, the IPv4 or IPv6 address of Sending toĭifferent destination transport addresses does not necessarily guarantee Specific destination transport address or its peer SCTP endpoint. Is the route taken by the SCTP packets sent by one SCTP endpoint to a Īn SCTP endpoint may have multiple associations. An SCTPĮndpoint can be represented as a list of SCTP transport addresses with the same Or more IP address but it always has one and only one SCTP port number. Only one association can be established between any two SCTP endpoints. Identified by the transport addresses used by the endpoints in the association.Īn SCTP association can be represented as a pair of SCTP endpoints, forĮxample, assoc =. This section defines some terms commonly found in SCTP standards and This approach to data delivery is more flexible than the single byte-stream used by TCP, as messages can be ordered, unordered or even unreliable within the same association. SCTP delivers discrete application messages within multiple logical streams within the context of a single association. Data delivery, however, is significantly different. In fact, it has inherited much of its behavior from TCP, such as association (an SCTP peer-to-peer connection) setup, congestion control and packet-loss detection algorithms. SCTP is designed to allow applications, represented as endpoints, communicate in a reliable manner, and so is similar to TCP. It provides acknowledged, error-free, non-duplicated transfer of messages through the use of checksums, sequence numbers, and selective retransmission mechanism. It is a reliable transport protocol operating on top of an unreliable connectionless service, such as IP. The Stream Control Transmission Protocol (SCTP) was originally designed by the Signaling Transport (SIGTRAN) group of IETF for Signalling System 7 (SS7) transport over IP-based networks.
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