.TH diameter_sctp 3erl "diameter 2.2.7" "Ericsson AB" "Erlang Module Definition"
.SH NAME
diameter_sctp \- Diameter transport over SCTP.
.SH DESCRIPTION
.LP
This module implements diameter transport over SCTP using gen_sctp(3erl)\&. It can be specified as the value of a transport_module option to diameter:add_transport/2 and implements the behaviour documented in diameter_transport(3erl)\&.
.SH EXPORTS
.LP
.B
start({Type, Ref}, Svc, [Opt]) -> {ok, Pid, [LAddr]} | {error, Reason}
.br
.RS
.LP
Types:

.RS 3
Type = connect | accept
.br
Ref = diameter:transport_ref()
.br
Svc = #diameter_service{}
.br
Opt = OwnOpt | SctpOpt
.br
Pid = pid()
.br
LAddr = inet:ip_address()
.br
Reason = term()
.br
OwnOpt = {raddr, inet:ip_address()} | {rport, integer()} | {accept, Match} | {unordered, boolean() | pos_integer()} | {packet, boolean() | raw} | {message_cb, diameter:eval()} | {sender, boolean()}
.br
SctpOpt = term()
.br
Match = inet:ip_address() | string() | [Match]
.br
.RE
.RE
.RS
.LP
The start function required by diameter_transport(3erl)\&.
.LP
Options \fIraddr\fR\& and \fIrport\fR\& specify the remote address and port for a connecting transport and not valid for a listening transport: the former is required while latter defaults to 3868 if unspecified\&. Multiple \fIraddr\fR\& options can be specified, in which case the connecting transport in question attempts each in sequence until an association is established\&.
.LP
Option \fIaccept\fR\& specifies remote addresses for a listening transport and is not valid for a connecting transport\&. If specified, a remote address that does not match one of the specified addresses causes the association to be aborted\&. Multiple \fIaccept\fR\& options can be specified\&. A string-valued \fIMatch\fR\& that does not parse as an address is interpreted as a regular expression\&.
.LP
Option \fIunordered\fR\& specifies whether or not to use unordered delivery, integer \fIN\fR\& being equivalent to \fIN =< OS\fR\&, where \fIOS\fR\& is the number of outbound streams negotiated on the association in question\&. Regardless of configuration, sending is ordered on stream 0 until reception of a second incoming message, to ensure that a peer receives capabilities exchange messages before any other\&. Defaults to \fIfalse\fR\&\&.
.LP
Option \fIpacket\fR\& determines how/if an incoming message is packaged into a diameter_packet record\&. If \fIfalse\fR\& then messages are received as binary()\&. If \fItrue\fR\& then as a record with the binary() message in the \fIbin\fR\& field and a \fI{stream, Id}\fR\& tuple in the \fItransport_data\fR\& field, where \fIId\fR\& is the identifier of the inbound stream the message was received on\&. If \fIraw\fR\& then as a record with the received ancillary sctp_sndrcvinfo record in the \fItransport_data\fR\& field\&. Defaults to \fItrue\fR\&\&.
.LP
Options \fImessage_cb\fR\& and \fIsender\fR\& have semantics identical to those documented in diameter_tcp(3erl), but with the message argument to a \fIrecv\fR\& callback being as directed by the \fIpacket\fR\& option\&.
.LP
An \fI{outstream, Id}\fR\& tuple in the \fItransport_data\fR\& field of a outgoing diameter_packet record sets the outbound stream on which the message is sent, modulo the negotiated number of outbound streams\&. Any other value causes successive such sends to cycle though all outbound streams\&.
.LP
Remaining options are any accepted by gen_sctp:open/1, with the exception of options \fImode\fR\&, \fIbinary\fR\&, \fIlist\fR\&, \fIactive\fR\& and \fIsctp_events\fR\&\&. Note that options \fIip\fR\& and \fIport\fR\& specify the local address and port respectively\&.
.LP
Multiple \fIip\fR\& options can be specified for a multihomed peer\&. If none are specified then the values of \fIHost-IP-Address\fR\& in the \fIdiameter_service\fR\& record are used\&. Option \fIport\fR\& defaults to 3868 for a listening transport and 0 for a connecting transport\&.
.LP

.RS -4
.B
Warning:
.RE
An small receive buffer may result in a peer having to resend incoming messages: set the inet(3erl) option \fIrecbuf\fR\& to increase the buffer size\&.
.LP
An small send buffer may result in outgoing messages being discarded: set the inet(3erl) option \fIsndbuf\fR\& to increase the buffer size\&.

.RE

.SH "SEE ALSO"

.LP
diameter(3erl), diameter_transport(3erl), gen_sctp(3erl), inet(3erl)