Load-balancing for SIP¶

Server1 performs a role of a load-distributor for Carrier1.
Its functions:

• incoming calls authorization
• signalling stream redirection to Server2 and Server3 using message SIP "302 Moved Temporarily"
• configuring of Web-interface
• periodic actions (Invoice generation etc)

This method works only for SIP protocol.

Server2 and Server3 act as SBC (Session Border Controller).
Their functions:

• Routing;
• Billing, Online billing and Balance maintenance;
• signalling protocols translation
• when a call is connected, signalling session maintenance with Carrier2 and Carrier3;
• media streams proxying
• media streams translation;
• VAS (if enabled);

The function distribution is approximate.
In the example below we assume, that resource spending on signalling handling from all customers are approximately equal to resources spendings to other functions (Billing, VAS, etc).
Maximal capacity of such a scheme is defined by maximal capacity by load-distributor Server1.
Therefore in example above it's shown how to maximally offload it.
In case if proportions will be different, it's possible to move some of functions from SBC to load-distributor.

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