Technical data

ServerIron ADX Advanced Server Load Balancing Guide 7
53-1002435-03
SIP SLB and call persistence using ServerIron ADX
1
• CANCEL
• BYE
• OPTIONS
Additionally, the following methods are supported:
• SUBSCRIBE
• NOTIFY
• Other proprietary methods
SIP and call persistence specifications
The SIP server load balancing has the following specifications:
• By default, server selection is persistent on Call-ID.
• Pass-through SIP traffic from real SIP servers to SIP clients gets translated. The ServerIron ADX
replaces the source IP (SIP server real IP) with Virtual IP (VIP).
• The ServerIron ADX does not modify any of the SIP header fields.
• The ServerIron ADX does not perform SIP-aware NAT.
• This implementation is based on RFC 3261.
NOTE
The ServerIron ADX SIP SLB is not implemented as a SIP proxy server, but rather as a load balancer
of proxy or registrar traffic.
Sample deployment topologies
ServerIron ADX switches offer application-aware advanced intelligence for SIP server load
balancing. The following sections describe some SIP server load balancing scenarios.
SIP server load balancing with DSR mode
Figure 3 shows an SIP server farm built around ServerIron ADX application switches.