In this section:

The SBC Core supports Stream Control Transmission Protocol (SCTP) as a transport for SIP. SCTP is an IETF transport-layer protocol which provides several enhancements over the Transport Control Protocol (TCP), including:

    • Message Orientation - SCTP transports individual messages, rather than a continuous byte stream. This allows SCTP to separate different signaling messages at the transport layer.
    • Ordered and Unordered Delivery - Assembling received bytes to form signaling messages is performed at the application layer; therefore TCP always delivers an ordered stream of bytes to the application. SCTP can deliver signaling messages to the application as soon as they arrive (when using the unordered service). The loss of a signaling message does not affect the delivery of the rest of the messages. This avoids the head of line blocking problem in TCP, which occurs when multiple higher layer connections are multiplexed within a single TCP connection.
    • Multiple Streams - Missing messages in one stream do not delay the delivery of messages in other streams. A SIP transaction can be considered an application layer connection: there are multiple transactions running between proxies. The loss of a message in one transaction should not adversely affect the ability of a different transaction to send a message. Thus, if SIP is run between entities with many transactions occurring in parallel, SCTP can provide improved performance over SIP over TCP. 

 

If the SCTP profile is not configured, then it will take the default SCTP profile. If the SCTP profile needs to be modified when associated with SIP signaling port, the port should be disabled for modification to take effect.

 

Multi-homing and IPv6 feature for SCTP are not supported in this release.

To View the SCTP Profile

On the SBC main screen, go to Configuration > Profile Management > Category: Signaling Profiles > SCTP Profile.

The SCTP Profile window opens.

Signaling Profiles - Sctp Profile

 

To Edit the SCTP Profile

To edit any of the SCTP Profile in the list, click the radio button next to the specific SCTP Profile name.

Signaling Profiles - Sctp Profile Highlighted

 

The Edit Selected SCTP Profile window is displayed below.

Signaling Profiles - Sctp Profile Edit Window

Make the required changes and click Save at the right hand bottom of the panel to save the changes made.

To Create the SCTP Profile

To create a new SCTP Profile, click New SCTP Profile tab on the SCTP Profile List panel.

Signaling Profiles - Sctp Profile Fields

 

The Create New SCTP Profile window is displayed.

Signaling Profiles - Sctp Profile Create Window

 

The following fields are displayed:

Sctp Profile Parameters

Parameter


Description

Name

Specifies the name of the SCTP Profile.

Outbound Streams

Specifies the number of Outbound Streams for this SCTP Profile. The values range from 1 to 32.

Inbound Streams

Specifies the number of Inbound Streams for this SCTP Profile. The value range from
1 to 32.

Peer Transport Addresses

Specifies the number of Peer Transport Addresses for this SCTP Profile. The allowed values for this field are 1 or 2.

Retransmissions Per Path

Specifies the number of Retransmission per path for this SCTP Profile. The value range from 1 to 10.

Heartbeat Interval

Specifies the SCTP Heartbeat Interval in seconds. The value range from 1 to 6.

Ordered Delivery

Specifies whether to enable the Ordered Delivery option for this SCTP profile or not. The options are:

  • enabled
  • disabled

Sack Delay

Specifies whether to enable the Sack Delay option for this SCTP Profile or not. The options are:

  • enabled
  • disabled

Retransmission Per Association

Specifies the maximum number of re-transmissions per SCTP Association. The value range from 0 to 20.

Rto Initial

Specifies the SCTP RTO initial in milliseconds. The value range from 50 to 500.

Rto Min

Specifies the SCTP RTO Minimum interval in milli seconds. The value range from 10 to 5000.

Rto Max

Specifies the SCTP RTO Maximum interval in milli seconds. The value range from 10 to 5000.

Init Retry

Specifies the maximum SCTP maximum Init Retry in milli seconds. The value range from 1 to 10.

Path Mtu

Specifies the SCTP Path MTU in bytes. The value range from 1000 to 1500.

Idle Timeout

Specifies the SCTP Idle Timeout interval in seconds. The value range from 0 to 86400.

To Copy SCTP Profile

To copy any of the created SCTP Profile and to make any minor changes, click the radio button next to the specific SCTP Profile to highlight the row.

Signaling Profiles - Sctp Profile Highlighted

 

Click Copy SCTP Profile tab on the SCTP Profile List panel.

Signaling Profiles - Sctp Profile Fields

 

The Copy Selected SCTP Profile window is displayed along with the field details which can be edited.

Signaling Profiles - Sctp Profile Copy Window

 

Make the required changes to the required fields and click Save to save the changes. The copied SCTP Profile is displayed at the bottom of the original SCTP Profile in the SCTP Profile List panel.

To Delete SCTP Profile

To delete any of the created SCTP Profile, click the radio button next to the specific SCTP Profile which you want to delete.

Signaling Profiles - Sctp Profile Highlighted

 

Click Delete at the end of the highlighted row. A delete confirmation message appears seeking your decision.

Signaling Profiles - Sctp Profile Delete Confirmation

 

Click OK to remove the specific SCTP Profile from the list.

 

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