[SR-Users] REGISTER replication using t_replicate with ds_select_dst

[Spencer Thomason]

Hello all,
We are moving our registration and location services to dedicated instances geographically separate from our proxies and then using redirects to locate the registered user.  The idea is to protect the proxies from a potential thundering herd of registrations if there was some network outage   I’m using dispatcher to find a registrar that has a registration for the user, if a user is not locally registered a 503 is returned and the next server is contacted.  Registrations are replicated to other servers when the client is not behind NAT.  If the client is behind NAT, the registrar where the client initially registered performs keep-alives and NAT traversal and also acts as an outbound proxy instead of sending a redirect.

I’m attempting to simplify the configuration by using a dispatcher group to classify incoming registrations and to select replication targets but the registrar that initially received the request is in the group as well.  Is there an elegant way to chose all destinations except the local instance?  I’m currently doing this with the hack below but any suggestions would be greatly appreciated.

Also, if anyone has any comments or recommendations on the topology, please share!

Thanks,
Spencer

    if (isflagset(FLT_FROMREG))
        return;

    subst('/^From:(.*)sip:.*@[a-zA-Z0-9.:]+(.*)$/From:\1sip:$au at DOMAIN\2/ig');
    subst('/^To:(.*)sip:.*@[a-zA-Z0-9.:]+(.*)$/To:\1sip:$au at DOMAIN\2/ig’);

    $rd = "DOMAIN";
    $var(local_uri) = "sip:" + $Ri + ":" + $Rp;
    ds_select_dst("10", "4");
    if ($du != $var(local_uri)) {
        t_replicate($du);
    }

    while (ds_next_dst()) {
        if ($du != $var(local_uri)) {
            t_replicate($du);
        }
    }