Parameters of the SCTP association.
| Field | Type | Description | Required | Default |
|---|---|---|---|---|
port |
Number | Must always equal 5000. | Yes | |
OS |
Number | Initially requested number of outgoing SCTP streams. | Yes | |
MIS |
Number | Maximum number of incoming SCTP streams. | Yes | |
maxMessageSize |
Number | Maximum allowed size for SCTP messages. | Yes |
| Field | Type | Description | Required | Default |
|---|---|---|---|---|
OS |
Number | Initially requested number of outgoing SCTP streams (from 1 to 65535). | No | 1024 |
MIS |
Number | Maximum number of incoming SCTP streams (from 1 to 65535). | No | 1024 |
Both OS and MIS are part of the SCTP INIT+ACK handshake. OS refers to the initial number of outgoing SCTP streams that the server side transport creates (to be used by DataConsumers), while MIS refers to the maximum number of incoming SCTP streams that the server side transport can receive (to be used by DataProducers). So, if the server side transport will just be used to create data producers (but no data consumers), OS can be low (~1). However, if data consumers are desired on the server side transport, OS must have a proper value and such a proper value depends on whether the remote endpoint supports SCTP_ADD_STREAMS extension or not.
SCTP_ADD_STREAMS so, if data consumers are required, OS should be 1024 (the maximum number of DataChannels that libwebrtc enables).SCTP_ADD_STREAMS so, if data consumers are required, OS can be lower (16 for instance). The mediasoup transport will allocate and announce more outgoing SCTM streams when needed.OS and MIS values via the device.sctpCapabilities getter.SCTP stream parameters describe the reliability of a certain SCTP stream.
| Field | Type | Description | Required | Default |
|---|---|---|---|---|
streamId |
Number | SCTP stream id | true | |
ordered |
Boolean | Whether data messages must be received in order. if true the messages will be sent reliably. | No | true |
maxPacketLifeTime |
Number | When ordered is false indicates the time (in milliseconds) after which a SCTP packet will stop being retransmitted. |
No | |
maxRetransmits |
Number | When ordered is false indicates the maximum number of times a packet will be retransmitted. |
No |
If ordered is true then maxPacketLifeTime and maxRetransmits must be false.
If ordered if false, only one of maxPacketLifeTime or maxRetransmits can be true.