NetScaler enables you to load balance SIP messages over UDP or over TCP (including TLS) to a group of proxy servers. NetScaler also provides Call-ID based persistence and Call-ID hash load balancing method using which you direct packets for a particular SIP session to the same load balanced SIP server. The NetScaler default expressions language contains a number of expressions that operate on Session Initiation Protocol (SIP) connections. These expressions are intended to be used in policies for SIP protocol that operates on a request/response basis. These expressions can be used in content switching, rate limiting, responder, and rewrite policies.

For more information, see Load Balancing a Group of SIP Servers.

Millions of short messages are exchanged daily between individuals and value-added service providers, such as banks, advertisers, and directory services, by using the short message peer to peer (SMPP) protocol. Often, message delivery is delayed because servers are overloaded and traffic is not optimally distributed among the servers. The NetScaler appliance provides optimal distribution of messages across your servers, preventing poor performance and outages. The NetScaler appliance:

Limitation: Message IDs, from the message center, longer than 59 bytes are not supported. If the message ID length returned by the message center is more than 59 bytes, ancillary operations fail and the NetScaler appliance responds with an error message.

For more information, see SMPP Load Balancing

Diameter is a base protocol with more than 50 protocols (also called applications) built over it. Therefore, the diameter traffic generated in a Telco network is high. To optimally maintain this diameter traffic, the NetScaler appliance performs load balancing, content switching, and acts as a relay agent. Additionally, the appliance offers rewrite and responder functionality. The appliance supports rate limiting of Diameter messages.

For more information, see Configuring Diameter Load Balancing.