[Serusers] Load Balancing

[Jiri Kuthan]

At 03:33 PM 4/22/2003, Alejandro Olchik wrote:


>I need some help to implement load balance
>when sending invites to an external sip
>proxy server.
>
>I would like to be able to balance load
>between to IPs (10.0.0.1 and 10.0.0.2) and
>use the backup IP when the primary one
>fails.
>
>Below is the routing code I have:
>
>
>        if (!lookup("location")) {
>                rewritehost("10.0.0.1");
>                if (!t_relay_to("10.0.0.1","5060")) {
>                        sl_send_reply("404", "Not Found");
>                };
>                break;
>        };
>
>How can I add this behaviour?

That depends on the distribution scheme you would like to use.
For example, you can implement a distribution function that 
splits requests based on some downstream weights.

e.g., 
   modparam("distrib", "weights", 
   # ...
   # rewrite host-part with one of values using the distribution
   # 20-30-50
   distribute("10.0.0.1/20%, 10.0.0.2/30%, 10.0.0.3/50%)
   t_on_negative("1")
   t_relay_to();
   # ...

reply_route[1] {
   # look at destinations that failed, and update their probabilities
   # according to some strategy; for example, temporary 0% weight --
   # note that this would take shared memory for keeping the weights
   # and a timer
   update_weights();
   # if coupled to TM, it can look at previous attempts to eliminate
   # retrying to a previously failed destination
   distribute("10.0.0.1/20%, 10.0.0.2/30%, 10.0.0.3/50%)
}

-Jiri