https://www.opensips.org/Documentation/Script-Routes-2-3

    route {
         if(is_method("OPTIONS")) {
            # send reply for each options request
            sl_send_reply("200", "ok");
            exit();
         }
         route(1);
    }
    route[1] {
         # forward according to uri
         forward();
    }

 route {
        lookup("location");
        t_on_branch("1");
        if(!t_relay()) {
            sl_send_reply("500", "relaying failed");
        }
    }
    branch_route[1] {
        if(uri=~"10\.10\.10\.10") {
            # discard branches that go to 10.10.10.10
            drop();
        }
    }

   route {
        lookup("location");
        t_on_failure("1");
        if(!t_relay()) {
            sl_send_reply("500", "relaying failed");
        }
    }
    failure_route[1] {
        if(is_method("INVITE")) {
             # call failed - relay to voice mail
             t_relay("udp:voicemail.server.com:5060");
        }
    }

route {
        seturi("sip:bob@opensips.org");  # first branch
        append_branch("sip:alice@opensips.org"); # second branch

        t_on_reply("global"); # the "global" reply route
                              # is set the whole transaction
        t_on_branch("1");

        t_relay();
}

branch_route[1] {
        if ($rU=="alice")
                t_on_reply("alice"); # the "alice" reply route
                                      # is set only for second branch
}

onreply_route {
        xlog("OpenSIPS received a reply from $si\n");
}


onreply_route[alice] {
        xlog("received reply on the branch from alice\n");
}

onreply_route[global] {
        if (t_check_status("1[0-9][0-9]")) {
                setflag(1);
                log("provisional reply received\n");
                if (t_check_status("183"))
                        drop;
        }
}

  error_route {
     xlog("--- error route class=$(err.class) level=$(err.level)
            info=$(err.info) rcode=$(err.rcode) rreason=$(err.rreason) ---\n");
     xlog("--- error from [$si:$sp]\n+++++\n$mb\n++++\n");
     sl_send_reply("$err.rcode", "$err.rreason");
     exit;
  }

  local_route {
     if (is_method("INVITE") && $ru=~"@foreign.com") {
        append_hf("P-hint: foreign request\r\n");
        exit;
     }
     if (is_method("BYE") ) {
        acc_log_request("internally generated BYE");
     }
  }

 startup_route {
    avp_db_query("select gwlist where ruleid==1",$avp(i:100));
    cache_store("local", "rule1", "$avp(i:100)");
  }

  timer_route[gw_update, 300] {
    avp_db_query("select gwlist where ruleid==1",$avp(i:100));
    $shv(i:100) =$avp(i:100);
  }

event_route[E_PIKE_BLOCKED] {
    xlog("The E_PIKE_BLOCKED event was raised\n");
  }
  event_route[E_PIKE_BLOCKED, async] {
    xlog("The E_PIKE_BLOCKED event was raised\n");
  }