In these days of the information society, new information is innumerably created, deleted and changed under very high speed network environments day after day.
Under an environment in which the network is connected at any place, a tendency to hold the information in common is gradually increasing.
A wired/wireless network environment is essential to hold the information in common. Data required for this network environment are sent in the format of a packet.
The data sent in the packet format are always sent to specified destinations through routes (paths), for instance, in broadcasting services.
Routing equipment such as a Layer 3 switch (L3 switch) or a router is required to determine the routes of the packets and guarantee effective, rapid transmission of traffic.
In order to determine the routes for transmission of the packets in routing equipment or in order to determine the paths (routes) between heterogeneous networks or between homogeneous networks, various routing protocols such as Open Shortest Path First (OSPF), Border Gateway Protocol (BGP), Router Information Protocol (RIP), MultiProtocol Label Switching (MPLS), OSPF version 3 (OSPFv3), and so forth are used.
A best route between pieces of equipment is determined using these routing protocols.
In order to use these routing protocols, the routers have their own identifier (ID) for mutual identification.
This ID generally uses an Internet Protocol (IP) address assigned to the interface of a system.
The ID used to identify the router is called a router ID, which is used by OSPF, BGP, RIP, MPLS, and so forth.
The router ID can be used for all kinds of communication equipment using the routing protocols and can be indispensable for effective operation of the communication equipment.
As illustrated in FIG. 1, a conventional network using at least one of these routing protocols includes an interface storage 10, an interface manager 20, one or more daemon processes 30-1 to 30-n, an command line interface (CLI) 40 and an event manager 50.
The router ID can be set through the CLI 40 by a user or be automatically set in the system if not set by the user. In detail, the router ID is automatically set in such a manner to designate the highest-priority IP address among IP addresses that loopback interfaces of the system have.
Here, the daemon processes 30-1 to 30-n get access to the interface storage 10 whenever the router ID is set, and then search for the highest-priority IP address among the IP addresses of the loopback interfaces or search and designate the highest-priority IP address among the IP addresses of the loopback interfaces through the interface manager 20.
The router ID is determined when each protocol is enabled. At that time, the router ID is adapted to set the highest-priority IP address of the loopback interface.
In other words, each of BGP, RIP and MPLS uses the highest-priority IP address of the loopback interface when enabled.
At this time, the router IDs used must be independently set for the respective protocols, and may be set independently or equally.
BGP uses one router ID for only one of the daemon processes 30-1 to 30-n enabled in the system, and OSPF uses the router IDs for the respective daemon processes 30-1 to 30-n. 
Thus, the router IDs must be set for the respective daemon processes.
Meanwhile, MPLS must use the router IDs for the respective daemon processes 30-1 to 30-n because it operates the numerous daemon processes 30-1 to 30-n. 
In this network supporting one or more protocols, the router IDs must be set for the respective protocols, and can be used for the IP addresses that are not set.
In the case of MPLS, the router ID must be set as the actual IP address assigned to the system.
However, in a network supporting one or more protocols, in the case in which the router ID is set when each protocol is enabled or when each of the daemon processes 30-1 to 30-n is enabled, a load is applied to the system because the highest-priority IP address must be looked up.
Further, in the network supporting one or more protocols, the router ID is fixed when each protocol is enabled. Thus, the router ID cannot be changed while using the protocol. In detail, when the router IDs of the daemon processes 30-1 to 30-n are required for immediate change while operating the network, a daemon or process of each protocol must be downed and then driven again.