enum shim_udp_msg_code {
        FLOW_REQ     = 1;
        FLOW_REPLY   = 2;
};

message shim_udp_msg {
        required shim_udp_msg_code code  = 1;
        optional string dst_name         = 2;
        optional string src_ae_name      = 4;
        required uint32 src_udp_port     = 5;
        optional uint32 dst_udp_port     = 6;
        optional sint32 response         = 7;
};