Local area network bridge
First Claim
1. Apparatus for establishing a bridge between a pair of communication networks, each of said networks being adapted to carry bit-serial message frames between devices coupled thereto, each said message frame having a leading portion including an address portion, said apparatus comprising:
- a pair of bridge sides each coupled to a respective one of said networks for transmitting and receiving message frames to and from its associated communication network;
memory means, accessible by said bridge sides, for retrievably storing message frames;
each of said bridge sides including;
interface means for receiving an incoming message frame from or transmitting an outgoing message frame to its associated communication network;
processor means for determining whether said incoming message frame is transmissible from one of said networks to the other, said processor means providing a first signal upon determining said incoming message frame is transmissible;
said processor means providing a second signal effective to initiate the transmission of said outgoing message frame;
controller means for directing said incoming message frame from said interface means to said memory means, said controller means responsive to said second signal to direct said outgoing message frame from said memory means to said interface means;
means for reading and storing the address portion of said incoming message frame concurrently with said controller means directing said incoming message frame to said memory means, the stored address portion being immediately accessible by said processor means for determining the transmissibility of said incoming message frame;
said pair of bridge sides coupled together such that each of said bridge sides can function as either a receiving bridge side for receiving said incoming message frame or a transmitting bridge side for transmitting said outgoing message frame; and
upon said processor means on said receiving bridge side providing said first signal, said processor means on said transmitting bridge side responsively providing said second signal to said controller means on said transmitting bridge side;
whereby said receiving bridge side address reading means reads and stores said address portion, said receiving bridge side processor means having immediate access to said address portion to determine therefrom the transmissibility of said incoming mesage frame concurrently with said controller means directing said incoming message frame to said memory means.
1 Assignment
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Accused Products
Abstract
Apparatus for bridging between two local area networks is disclosed. The apparatus has two bridge sides each including means for receiving or transmitting a message frame, controller means for directing an incoming message frame into a memory means shared between the bridge sides or directing a frame out of the memory means for transmission, address reading means for reading an address portion of the incoming frame and processor means for determining frame transmissibility from the address portion as provided by the address reading means. The apparatus is configured such that the processor means determines incoming frame transmissibility substantially concurrent with the controller means directing the incoming frame into the memory means.
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Citations
24 Claims
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1. Apparatus for establishing a bridge between a pair of communication networks, each of said networks being adapted to carry bit-serial message frames between devices coupled thereto, each said message frame having a leading portion including an address portion, said apparatus comprising:
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a pair of bridge sides each coupled to a respective one of said networks for transmitting and receiving message frames to and from its associated communication network; memory means, accessible by said bridge sides, for retrievably storing message frames; each of said bridge sides including; interface means for receiving an incoming message frame from or transmitting an outgoing message frame to its associated communication network; processor means for determining whether said incoming message frame is transmissible from one of said networks to the other, said processor means providing a first signal upon determining said incoming message frame is transmissible; said processor means providing a second signal effective to initiate the transmission of said outgoing message frame; controller means for directing said incoming message frame from said interface means to said memory means, said controller means responsive to said second signal to direct said outgoing message frame from said memory means to said interface means; means for reading and storing the address portion of said incoming message frame concurrently with said controller means directing said incoming message frame to said memory means, the stored address portion being immediately accessible by said processor means for determining the transmissibility of said incoming message frame; said pair of bridge sides coupled together such that each of said bridge sides can function as either a receiving bridge side for receiving said incoming message frame or a transmitting bridge side for transmitting said outgoing message frame; and upon said processor means on said receiving bridge side providing said first signal, said processor means on said transmitting bridge side responsively providing said second signal to said controller means on said transmitting bridge side; whereby said receiving bridge side address reading means reads and stores said address portion, said receiving bridge side processor means having immediate access to said address portion to determine therefrom the transmissibility of said incoming mesage frame concurrently with said controller means directing said incoming message frame to said memory means. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A method for bridging between a pair of communication networks, each of said networks being adapted to carry bit-serial message frames between devices coupled thereto, each of said message frames including an address portion, said bridge comprising a pair of bridge sides coupled together such that each of said bridge sides can function as either a receiving bridge side or a transmitting bridge side respectively for either receiving an incoming message frame from or transmitting an outgoing message frame to its associated network, said pair of bridge sides sharing memory means for storing a message frame, said method comprising the steps of:
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receiving said incoming message frame on said receiving bridge side from the network associated therewith; directing said incoming message frame to said memory means for storage therein; reading said address portion of said incoming frame concurrently with said directing step; determining on said receiving bridge side whether said incoming message frame is transmissible to the network associated with said transmitting bridge side, said determining step being performed using said address portion acquired in said reading step; discarding said incoming message frame if it is determined to be not transmissible; sending a signal from said receiving bridge side to said transmitting bridge side if said incoming message frame is determined to be transmissible; and directing the transmissible incoming message frame, as said outgoing message frame, from said memory means to the communication network associated with said transmitting bridge side. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24)
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Specification