How to configure SCTP Multi-homing

Introduction: 

Multi-homing is a core feature of SCTP: it allows a single SCTP endpoint to support multiple IP addresses. 

It should be noted that SCTP multihoming support only deals with communication between two endpoints which are assigned with multiple IP addresses on possibly multiple network interfaces. It does NOT deal with configurations that contain multiple endpoints (for example: clustered endpoints) that can switch over to an alternate endpoint in case of failure of the original endpoint.

Configure Multi IP Networks 

Open

In the configuration sample shown above, the primary SCTP IP address is configured on the 10.129.51.x subnet using the Dialogic IMG Integrated Media Gateway DATA port interface while the alternate SCTP IP address is configured on 192.168.20.x subnet using the IMG SIG port interface. SIG and Data ports MUST be connected to separate physical devices. 


Configure Multi-homing SCTP links

Please click on the following image to view it full-size 

Open

In the configuration sample shown above, the primary SCTP IP address (10.129.51.19) on the IMG is configured at Local IP 1 while the remote endpoint's primary SCTP IP address (10.129.51.9) is configured at Remote IP 1. The alternate SCTP IP address (192.168.20.251) on the IMG is configured at Local IP 2 while the remote endpoint's alternate  SCTP IP address (192.168.20.250) is configured at Remote IP 2.

Heartbeat on Alternate SCTP Link:

SCTP does not do load sharing. The primary SCTP link is used as the destination for all DATA chunks for normal transmission. Retransmitted DATA chunks use the alternate address to improve the probability of reaching the remote endpoint, while continued failure to send to the primary address ultimately results in the decision to transmit all DATA chunks to the alternate until heartbeats can re-establish the reachability of the primary.

Heartbeat chunks are sent periodically to primary and alternate SCTP links, and a counter is maintained on the number of Heartbeats sent to an inactive destination without receipt of a corresponding Heartbeat Ack. When this counter exceeds a configured maximum, that destination address is also declared inactive.

Here is an example of Heartbeat sending on alternate SCTP Link:

Click on the following image to display it full-size:

Product List:
Dialogic IMG 1010 Integrated Media Gateway

Glossary of Acronyms / Terms:
SCTP - Stream Control Transmission Protocol
MTP3 - Message Transfer Part 3
M3UA - MTP3 User Adaptation Layer