1. Field of Invention
The present invention relates to the assigning of MAC addresses to clients of a local area network system.
2. The Background Art
The widespread use and acceptance of the Internet has generated much excitement, especially among those who see advantages in networking their voice, data and graphical communications.
Many individuals, businesses, schools and others use a local-area network (“LAN”) as their network system or the LAN may be part of a larger network system. A LAN is a short-distance data communications network (which may be within a building or campus) used to link together computers and peripheral devices under some form of standard control.
When using a LAN, a MAC address is required. A MAC address is a standardized data link layer that is required for every port or device that connects to a LAN. Other devices in the network use these MAC addresses to locate specific ports in the network and to create and update routing tables and data structures. “MAC” stands for Media Access Control which is the lower of the two sublayers of the data link layer defined by the IEEE. The MAC sublayer handles access to shared media, such as whether token passing or contention will be used.
A method and apparatus for automatically assigning a locally administered MAC address to at least one client in a local area network (“LAN”) system, and a method and apparatus for detecting duplicate locally administered MAC addresses, where the LAN system comprises at least one client and may comprise at least one server.
The present invention is described in greater detail by referencing the accompanying drawings.
a is a flowchart of one embodiment of the disclosed method, showing the client-side method.
b is another flowchart of one embodiment of the disclosed method, showing the client-side method.
a is a flowchart of one embodiment of the disclosed method, showing the server-side method.
b is another flowchart of one embodiment of the disclosed method, showing the server-side method.
Those of ordinary skill in the art will realize that the following description of the present invention is illustrative only and not in any way limiting. Other embodiments of the invention will readily suggest themselves to such skilled persons.
This disclosure may relate to data communications. Various disclosed aspects may be embodied in various computer and machine readable data structures. Furthermore, it is contemplated that data structures embodying the teachings of the disclosure may be transmitted across computer and machine readable media, and through communications systems by use of standard protocols such as those used to enable the Internet and other computer networking standards.
This disclosure may relate to any network known in the art, such as a packet or frame based network including an Ethernet and networks capable of running the TCP/IP protocol.
The disclosure may relate to machine readable media on which are stored various aspects of the disclosure. It is contemplated that any media suitable for retrieving instructions is within the scope of the present disclosure. By way of example, such media may take the form of magnetic, optical, or semiconductor media, and may be configured to be accessible by a machine as is known in the art.
Various aspects of the disclosure may be described through the use of flowcharts. Often, a single instance of an aspect of the present disclosure may be shown. As is appreciated by those of ordinary skill in the art, however, the protocols, processes, and procedures described herein may be repeated continuously or as often as necessary to satisfy the needs described herein. Accordingly, the representation of various aspects of the present disclosure through the use of flowcharts should not be used to limit the scope of the present disclosure.
The present disclosed system will automatically assign a locally administered MAC address to a port or device coupled to a LAN. These ports or devices may also be referred to as “clients”. Non-limiting examples of ports and devices may be routers, personal computers, printers, faxes, and file servers. The presently disclosed system may be comprised of algorithm residing in a LAN client and if there is a LAN server present, an algorithm residing in the LAN server.
The invention relates to the assignment and/or detection of locally administered MAC addresses. Most devices which connect to a LAN have a built in MAC address which is meant to be globally unique. However, there is a large range of addresses which are specifically meant to be locally administered, e.g. they can be assigned for use on a LAN by a local administrator. This makes them especially useful for protocol developers who require a range of MAC addresses for their protocol (e.g. the same address range would be used on every LAN on which the protocol is implemented). One possible problem is that there is no way to guarantee that the addresses chosen are unique within the LAN. MAC addresses have to be unique on a given LAN for proper communication at the datalink layer.
Locally administered MAC addresses look exactly the same as normal MAC addresses with the exception that bit 2 of the first byte of the MAC address is set to 1. This gives a range of addresses which are 2 to the power of 46 in size. The disclosed system may be used with or without a server on the network.
Referring to
Referring to
In a simple case, a client (computer or otherwise) will broadcast an address request frame. If no response is received within a given time period, the client will assume that it is OK to use the address requested and will start periodically broadcasting the fact that these addresses are in use. This allows other clients to detect whether the addresses they would like to use are in use or are free.
If another client is using the same MAC address that is being broadcast in the MAC address advertisement frame from act 116, then that client will respond to that broadcast by sending a duplicate MAC address frame, notifying the system that that MAC address has already been assigned. Thus, at query 120, the client determines whether it has received a duplicate MAC address frame from any other clients. If the client has received a duplicate MAC address frame, then at act 124, the client will reject the MAC address.
If no duplicate MAC address frames are received, then the method proceeds to act 136 where the client monitors again broadcasts of MAC address advertisement frames from other clients. This act is described as “monitors again . . . ” to differentiate this act from act 104. At act 140, the client determines whether any broadcast MAC address advertisement frames are advertising any MAC addresses used by the client, if so, the client will send a duplicate MAC address frame informing the client that is broadcasting a MAC address advertisement frame, that it is already using the MAC address at act 144.
Referring to
If another client is using the same MAC address that is being broadcast in the MAC address advertisement from act 216, that client will respond by sending a duplicate MAC address frame, notifying the system that that MAC address has already been assigned. Thus, at query 220, the client determines whether it has received a duplicate MAC address frame from any other clients. If no duplicate MAC address frames are received, then the method proceeds to act 224. If a duplicate MAC address frame is received, the client can reject the MAC address it previously requested at act 248. Then, the client may send a warning message indicating that it does not have a MAC address at act 252.
At act 224 the client monitors again broadcasts of MAC address advertisement frames from other clients. This act is described as “monitors again . . . ” to differentiate this act from act 204. At query 228, the client determines whether any MAC address advertisements are advertising any MAC addresses used by the client, if so, the client will send a duplicate MAC address frame informing the system that it is already using the MAC address at act 232.
Referring to
If another client is using the same MAC address that is being broadcast in the MAC address advertisement from act 316, that client will respond by sending a duplicate MAC address frame, notifying the system that that MAC address has already been assigned. Thus, at query 320, the client determines whether it has received a duplicate MAC address frame from any other clients. If no duplicate MAC address frames are received, then the method proceeds to act 328. If a duplicate MAC address frame is received, the client can reject the MAC address it previously requested at act 324, then return to act 302 where it selects a different MAC address.
At act 328 the client monitors again broadcasts of MAC address advertisement frames from other clients. This act is described as “monitors again . . . ” to differentiate act 328 from act 304. At query 332, the client determines whether any MAC address advertisements are advertising any MAC addresses used by the client, if so, the client will send a duplicate MAC address frame informing the system that it is already using the MAC address at act 336.
If the LAN has a server, then referring to
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While embodiments and applications of this invention have been shown and described, it would be apparent to those skilled in the art that many more modifications than mentioned above are possible without departing from the inventive concepts herein. The invention, therefore, is not to be restricted except in the spirit of the appended claims.
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