Load Balance Control-Plane Traffic that is based on Diameter, SIP, and SMPP Protocols

With the increase in control-plane traffic, the servers can become a bottleneck because the traffic is not optimally distributed among the servers. Therefore, messages must be load balanced. The Citrix ADC appliance supports Diameter, SIP, and SMPP load balancing.


Citrix ADC enables you to load balance SIP messages over UDP or over TCP (including TLS) to a group of proxy servers. Citrix ADC 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 Citrix ADC 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 Citrix ADC appliance provides optimal distribution of messages across your servers, preventing poor performance and outages. The Citrix ADC appliance:

  • Load balances messages originating from the server and from the client
  • Monitors the health of the message centers
  • Provides content switching support for the message centers
  • Handles concatenated messages

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 Citrix ADC 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 Citrix ADC 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.

Load Balance Control-Plane Traffic that is based on Diameter, SIP, and SMPP Protocols