Local area network with self assigned address method
First Claim
1. An apparatus for assigning a unique address to a data processing device coupled to a communication medium to permit the transfer of data between a plurality of said agents on said medium, comprising:
- transceiver means coupled to each of said agents for transmitting signals onto said medium and receiving signals transmitted on said medium by another agent;
address assignment means coupled to each of said agents to permit each of said agents to assign itself a unique address on said communication medium, said address assignment means including;
random number generating means for generating a random number within a predefined range for use as a tentative address;
address storage means coupled to said random number generating means for storing said tentative address;
first signal generation means coupled to said address storage means and said transceiver means for generating an enquiry (ENQ) signal and transmitting at least one said ENQ signal to a device having said tentative address on said communication medium;
acknowledge signal receiving means coupled to said transceiver means for receiving an acknowledge (ACK) signal transmitted by an agent other than said agent being assigned a unique address in response to its receipt of said ENQ signal, said acknowledge receiving means signalling said random number generating means to generate another random number as a tentative address upon the receipt of said ACK signal;
timing means coupled to said acknowledge signal receiving means for storing said tentative address as a final address in said address storage means in the absence of the receipt of said ACK signal within a predetermined time (IFG) after the last ENQ signal has been transmitted;
whereby said agent is assigned a unique address on said communication medium.
1 Assignment
0 Petitions
Accused Products
Abstract
A local area network is disclosed including apparatus and methods for transferring data between a plurality of data processing resources ("agents") coupled to a cable. In the preferred embodiment, a plurality of agents are coupled to a common cable for data transmission and reception. An agent newly coupled to the cable dynamically assigns itself a unique address on the cable to which other agents may send data. Once an agent has been assigned a final address, it may then transmit to, and receive data from, other agents on the cable. An agent desiring to send data to a receiving agent follows a three step handshake, wherein the sending agent transmits an "RTS" signal and within a predetermined time must receive a "CTS" signal from the receiving agent. The sending agent then transmits a data frame within a predetermined time after the CTS signal is received. The failure to detect a return CTS signal within the predetermined time denotes a collision condition. Re-transmission is attempted using a linear back off method which is adjusted based on previous cable traffic history.
-
Citations
19 Claims
-
1. An apparatus for assigning a unique address to a data processing device coupled to a communication medium to permit the transfer of data between a plurality of said agents on said medium, comprising:
-
transceiver means coupled to each of said agents for transmitting signals onto said medium and receiving signals transmitted on said medium by another agent; address assignment means coupled to each of said agents to permit each of said agents to assign itself a unique address on said communication medium, said address assignment means including; random number generating means for generating a random number within a predefined range for use as a tentative address; address storage means coupled to said random number generating means for storing said tentative address; first signal generation means coupled to said address storage means and said transceiver means for generating an enquiry (ENQ) signal and transmitting at least one said ENQ signal to a device having said tentative address on said communication medium; acknowledge signal receiving means coupled to said transceiver means for receiving an acknowledge (ACK) signal transmitted by an agent other than said agent being assigned a unique address in response to its receipt of said ENQ signal, said acknowledge receiving means signalling said random number generating means to generate another random number as a tentative address upon the receipt of said ACK signal; timing means coupled to said acknowledge signal receiving means for storing said tentative address as a final address in said address storage means in the absence of the receipt of said ACK signal within a predetermined time (IFG) after the last ENQ signal has been transmitted; whereby said agent is assigned a unique address on said communication medium. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
-
-
13. In a communication system for transferring data between a plurality of devices, a method used by each of said agents for assigning itself a unique address on said communication system, comprising the steps of:
-
generating a random number within a predetermined range for use as a tentative address; storing said tentative address in storage means; generating an enquiry (ENQ) signal and transmitting said ENQ signal to a device having said tentative address on said communication system; sensing said communication medium for the reception of an acknowledge (ACK) signal transmitted by an agent other than said agent being assigned a unique address in response to its receipt of said ENQ signal, and upon sensing said ACK signal generating another random number for use as an alternate tentative address; storing said tentative address as a final address in said storage means in the absence of the receipt of said ACK signal within a predetermined time (IFG) after the transmission of said ENQ signal; whereby an agent is assigned a unique address on said communication system. - View Dependent Claims (14, 15, 16, 17, 18, 19)
-
Specification