Electrical computers and digital processing systems: multicomput – Network-to-computer interfacing
Reexamination Certificate
1998-07-01
2001-06-12
An, Meng-Al T. (Department: 2154)
Electrical computers and digital processing systems: multicomput
Network-to-computer interfacing
C709S220000, C709S221000, C709S222000, C709S228000, C709S241000, C709S241000, C710S100000, C710S104000, C340S870030, C340S870030, C370S463000, C375S219000, C375S220000, C375S222000
Reexamination Certificate
active
06247063
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a network terminal equipment wherein a plurality of communication control units can be installed in one terminal equipment, such as a workstation or the like, and more particularly to network terminal equipment, such as a workstation, that can accommodate a plurality of communication control units to permit connection by a plurality of protocols and/or to realize a dual configuration of the communication control unit.
2. Description of the Related Art
Each terminal equipment connected to a local area network (LAN), such as an Ethernet or an FDDI (fiber distributed data interface) network, is assigned a medium access control (MAC) address for uniquely identifying the terminal equipment in the network.
Conventionally, the MAC address has been assigned to each individual LAN control unit that is plugged into a slot in a workstation and that controls transmission and reception to and from LAN transmission channels. The MAC address is written in a ROM or like memory which is mounted on the LAN control unit. The reason that the MAC address is stored in a ROM or like memory is to prevent accidental alteration of the MAC address that could lead to a malfunction in the network.
If the LAN control unit has failed, it has to be replaced with a new unit. Since the same MAC address as that of the failed unit must be assigned to the new unit, the ROM holding the MAC address (hereinafter referred to as the MAC ROM) has to be removed from the failed unit and mounted on the new unit.
Previously, it has sometimes practiced to install the MAC ROM in the workstation itself, not on the LAN control unit. In such cases, if the LAN control unit has failed, it is simply replaced with a new unit.
If the known method described above is to be adopted for a workstation capable of accommodating a plurality of LAN control units in its slots to permit connection by a plurality of protocols and/or to realize a primary/spare dual configuration with two LAN control units, the workstation itself must be constructed to accommodate a plurality of MAC ROMs to correspond with the plurality of LAN control units. Furthermore, the plurality of MAC ROMs must have a one-to-one correspondence with the plurality of LAN control units to ensure the uniqueness of the MAC address. Moreover, when two LAN control units are used in a dual configuration, one as the primary and the other as the spare, the two control units must be constructed to be able to access a common MAC ROM, while disabling or prohibiting the operation of the spare LAN control unit by some means in order to ensure the uniqueness.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a construction that facilitates the replacement of communication control units for a network terminal equipment capable of accommodating a plurality of communication control units.
It is another object of the present invention to provide means for ensuring the uniqueness of a MAC address for a network terminal equipment capable of accommodating a plurality of communication control units.
According to the present invention, there is provided a network terminal equipment comprising: a plurality of slots each capable of accommodating a communication control unit; at least one socket for holding therein a memory device where fixed data is stored that is used by each of the plurality of communication control units installed in the slots; and an input/output control unit for determining a correspondence between the communication control units installed in the slots and the memory device mounted in the socket.
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Ichimi Masahiro
Koinuma Hideyuki
Mori Ken-ichi
An Meng-Al T.
Fujitsu Limited
Najjar Saleh
Staas & Halsey , LLP
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