In this section:
Stream Control Transmission Protocol (SCTP) is a transport layer protocol similar to TCP, but is characterized as message-oriented protocol transporting a sequence of messages (each being a group of bytes) rather than an unbroken stream of bytes (TCP behavior). In SCTP, a sender sends a message in one operation, and that exact message is passed to the receiving application process in one operation.
The SCTP as a Transport preference and SCTP retransmission timer are configured from the SIP Trunk Group. The SCTP as a transport protocol and SCTP profile are configured in the SIP signaling port. The SCTP Profile CLI syntax is described below.
Command Syntax
% set profiles signaling sctpProfile <profile name> heartbeatInterval <# seconds> idleTimeout <# seconds> inboundStreams <#> initRetry <#> orderedDelivery <disabled|enabled> outboundStreams <#> pathMtu <#bytes> peerTransportAddresses <# addresses> retransmissionsPerAssociation <#> retransmissionsPerPath <#> rtoInitial <# milliseconds> rtoMax <# milliseconds> rtoMin <# milliseconds> sackDelay <disabled|enabled>
Command Parameters
The SCTP Profile Parameters are as shown below:
SCTP Profile Parameters
Parameter | Length/Range | Description |
---|---|---|
| 1-23 characters | <SCTP profile name> – The name of the SCTP Profile. |
| 1-6 | The SCTP heartbeat interval in seconds. (default = 4) |
| 0-86400 | SCTP Idle timeout Interval in seconds. (default = 3600) |
| 1-32 | The number of inbound streams for this SCTP profile. (default = 1) |
| 1-10 | The SCTP maximum INIT retry. (default = 8) |
| N/A | Enable flag to use ordered delivery method in SCTP.
|
| 1-32 | The number of outbound streams for this SCTP profile. |
| 1000-1500 | The maximum packet size (Maximum Transmission Unit [MTU]), in bytes, to transmit. (default = 1500) |
| 1-2 | The number of peer transport addresses for this SCTP profile. (default = 1) |
| 0-20 | The maximum retransmissions per SCTP association. (default = 0) |
| 1-10 | The number of retransmissions per path for this SCTP profile. (default = 8) |
| 50-500 | The SCTP Retransmission Timeout (RTO) initial value in milliseconds. (default = 50) |
| 200-5000 | The SCTP RTO maximum value in milliseconds. (default = 200) |
| 10-5000 | The SCTP RTO minimum value in milliseconds. (default = 40) |
| N/A | Set flag to enable SACK Delay in this SCTP profile.
|
Command Example
In this example, the following steps are accomplished:
- Create SCTP profile named "SCTP02" with following configuration: outboundStreams - 2, inboundStreams - 2, peerTransportAddress - 2, retransmissionsPerPath - 8, hearbeatInterval - 6, orderedDelivery - enabled, retransmissionPerAssociatioon - 1, rtoInitial - 100, rtoMax - 200, rtoMin - 50.
- Configure SCTP as a transport protocol in SIP signaling port, and SCTP profile "SCTP02" is associated with the particular zone.
- Configure SCTP as a Transport preference and SCTP retransmission timer to 50 seconds in the SIP Trunk Group.
- Configure SCTP as a transport protocol in IP Signaling Profile.
Step | Action |
---|---|
1 | set profiles signaling sctpProfile SCTP02 outboundStreams 2 inboundStreams 2 peerTransportAddresses 2 retransmissionsPerPath 8 heartbeatInterval 6 orderedDelivery enabled retransmissionsPerAssociation 1 rtoInitial 100 rtoMax 200 rtoMin 50 commit show profiles signaling sctpProfile SCTP02 outboundStreams 2; inboundStreams 2; peerTransportAddresses 2; retransmissionsPerPath 8; heartbeatInterval 6; orderedDelivery enabled; retransmissionsPerAssociation 1; rtoInitial 100; rtoMin 50; rtoMax 200; |
2 | set addressContext ADDR_CONTEXT_1 zone ZONE_AS sipSigPort 2 transportProtocolsAllowed sip_sctp set addressContext ADDR_CONTEXT_1 zone ZONE_AS sipSigPort 2 sctpProfileName SCTP02 commit |
3 | set addressContext ADDR_CONTEXT_1 zone ZONE_AS sipTrunkGroup TG_SIPART_AS signaling transportPreference preference1 1 set addressContext ADDR_CONTEXT_1 zone ZONE_AS sipTrunkGroup TG_SIPART_AS signaling timers sctpRetransmitTimer 10 commit |
4 | set profiles signaling ipSignalingProfile DEFAULT_SIP egressIpAttributes transport type1 sctp commit |