code: private Node checkRouteHeaderForSipNode(SipURI routeSipUri) {
          Node node = null;
          String hostNode = routeSipUri.getParameter(ROUTE_PARAM_NODE_HOST);
          String hostPort = routeSipUri.getParameter(ROUTE_PARAM_NODE_PORT);
          String hostVersion = routeSipUri.getParameter(ROUTE_PARAM_NODE_VERSION);
          if(hostNode != null && hostPort != null) {
              int port = Integer.parseInt(hostPort);
              String transport = routeSipUri.getTransportParam();
              if(transport == null) transport = ListeningPoint.UDP;
              node = register.getNode(hostNode, port, transport, hostVersion);                       
          }
          return node;
      }
docs: This will check if in the route header there is information on which node from the cluster send the request.
  If the request is not received from the cluster, this information will not be present.
  @param routeHeader the route header to check
  @return the corresponding Sip Node