EP0374883A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
System for internetwork communication between local area networks
Assignee: Fujitsu Ltd
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Filing: 1989-12-20
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Granted: —
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Expires: 2009-12-20
Abstract
Abstract An internetwork communication system provides communication from a first local area network to a second, ring-type, local area network via a bridge. The bridge receives a frame from the first local area network and transmits a dummy frame followed by an internetwork transfer frame to the second local area network. The internetwork transfer frame defines a node of the second local area network as a distant apparatus (receiver) and a node of the first local area network as a self apparatus (sender). The bridge later receives the dummy frame from the second local area network, after transmission of the dummy frame around the ring, and deletes the dummy frame and the internetwork transfer frame received following the dummy frame so that the communication in the second local area network does not circulate indefinitely around the ring. As an alternative to using a dummy frame, the bridge can receive the internetwork transfer frame, after circulation around the second local area network, and compare the distant apparatus of the received internetwork transfer frame with a stored distant apparatus address. When the received distant apparatus address matches the stored distant apparatus address, the bridge deletes the internetwork transfer frame from the second local area network.
Inventors
- 👤 Toshimitsu Ohba
- 👤 Shigehiro Hayashi
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-06 23:22
CPC Classifications
H; H04; H04L; H04L12/00; H04L12/28; H04L12/46; H04L12/4637; H04L12/4604; H04L12/462; H04L12/4625
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
87 words
A system for communication between a first local area network and a second local area network, the second local area network being a ring-type local area network, said system comprising: a transmitter to transmit, to the second local area network, a first dummy frame followed by at least one internetwork transfer frame; and a detector to detect the first dummy frame after transmission around the second local area network and to delete the at least one internetwork transfer frame immediately following detection of the first dummy frame.
Claim 2
Independent Claim
87 words
A system for communication between a first local area network and a second local area network, the second local area network being a ring-type local area network, said system comprising: a transmitter to transmit, to the second local area network, a first dummy frame followed by at least one internetwork transfer frame; and a detector to detect the first dummy frame after transmission around the second local area network and to delete the at least one internetwork transfer frame immediately following detection of the first dummy frame.
Claim 3
Dependent Claim
73 words
A system as recited in claim 1, wherein said transmitter transmits a second dummy frame to the second local area network following the at least one internetwork transfer frame, and wherein said detector detects the second dummy frame received after circulation through the second local area network and deletes one or more internetwork transfer frames received during a period between reception of the first dummy frame and reception of the second dummy frame.
Claim 4
Dependent Claim
54 words
The system as recited in claim 1, wherein said transmitter comprises an identifier to identify a number of internetwork transfer frames to be transmitted after transmission of the first dummy frame, and wherein said detector deletes as many of the internetwork transfer frames, received following the first dummy frame, as specified by said identifier.
Claim 5
Dependent Claim
24 words
A system as recited in claim 3, wherein said identifier comprises a counter to count the number of internetwork transfer frames transmitted and received.
Claim 6
Dependent Claim
45 words
A system as recited in claim 4, wherein said counter, beginning at zero, increments for each transmitted internetwork transfer frame and decrements for each later received internetwork transfer frame, and wherein said detector completes deleting received internetwork transfer frames when said counter decrements to zero.
Claim 7
Dependent Claim
49 words
A system as recited in claim 1, wherein said transmitter transmits data in the at least one internetwork transfer frame defining a node of the first local area network by a self apparatus address and defining a node of the second local area network by a distant apparatus address.
Claim 8
Independent Claim
120 words
A system for communication between a first local area network and a second local area network, the second local area network being a ring-type local area network, said system comprising: a memory; a transmitter to transmit, to the second local area network, an internetwork transfer frame, the internetwork transfer frame comprising a distant apparatus address, and to store the distant apparatus address of the internetwork transfer frame in said memory; and a detector to detect the internetwork transfer frame after transmission around the second local area network and to delete the internetwork transfer frame when the distant apparatus address of the internetwork transfer frame received from the second local area network matches the distant apparatus address stored in said memory.
Claim 9
Independent Claim
120 words
A system for communication between a first local area network and a second local area network, the second local area network being a ring-type local area network, said system comprising: a memory; a transmitter to transmit, to the second local area network, an internetwork transfer frame, the internetwork transfer frame comprising a distant apparatus address, and to store the distant apparatus address of the internetwork transfer frame in said memory; and a detector to detect the internetwork transfer frame after transmission around the second local area network and to delete the internetwork transfer frame when the distant apparatus address of the internetwork transfer frame received from the second local area network matches the distant apparatus address stored in said memory.
Claim 10
Dependent Claim
46 words
A system as recited in claim 7, wherein said transmitter transmits data in the internetwork transfer frame defining a node of the first local area network by a self apparatus address and defines a node of the second local area network by the distant apparatus address.
Claim 11
Dependent Claim
30 words
A system as recited in claim 7, wherein said detector comprises a comparator for comparing a received internetwork transfer frame with at least one stored frame to recognize a match.
Claim 12
Dependent Claim
65 words
A system as recited in claim 9, wherein each of the at least one stored frame includes a flag indicating transfer frames that have been transmitted and not yet received, and wherein said comparator compares the received internetwork transfer frame with the at least one stored frame when the flag therein indicates that a transfer frame corresponding thereto has been transmitted and not yet received.
Claim 13
Independent Claim
80 words
A method for communication between a first local area network and a second local area network, the second local area network being a ring-type local area network, said method comprising the steps of: (a) transmitting, to the second local area network, a first dummy frame followed by an internetwork transfer frame; (b) detecting the first dummy frame after transmission around the second local area network; and (c) deleting an internetwork transfer frame immediately following detection of the first dummy frame.
Claim 14
Independent Claim
80 words
A method for communication between a first local area network and a second local area network, the second local area network being a ring-type local area network, said method comprising the steps of: (a) transmitting, to the second local area network, a first dummy frame followed by an internetwork transfer frame; (b) detecting the first dummy frame after transmission around the second local area network; and (c) deleting an internetwork transfer frame immediately following detection of the first dummy frame.
Claim 15
Dependent Claim
73 words
A method as recited in claim 11, further comprising the steps of: (d) transmitting a second dummy frame to the second local area network following at least one internetwork transfer frame; (e) detecting the second dummy frame received after circulation through the second local area network; and (f) deleting at least one internetwork transfer frame received during a period between reception of the first dummy frame and reception of the second dummy frame.
Claim 16
Dependent Claim
58 words
The method as recited in claim 11, further comprising the steps of: (d) identifying a number of internetwork transfer frames to be transmitted after transmission of the first dummy frame; and (e) deleting as many internetwork transfer frames, received following the first dummy frame, as specified by the number of the internetwork transfer frames identified in step (d).
Claim 17
Dependent Claim
28 words
A method as recited in claim 13, wherein said identifying in step (d) comprises the step of counting the number of the internetwork transfer frames transmitted and received.
Claim 18
Dependent Claim
52 words
A method as recited in claim 14, wherein said counting in step (d), beginning at zero, increments for each transmitted internetwork transfer frame and decrements for each later received internetwork transfer frame, and wherein said deleting of received internetwork transfer frames in step (f) is complete when said count decrements to zero.
Claim 19
Dependent Claim
51 words
A method as recited in claim 11, wherein said method further comprises the step of (d) defining, prior to said transmitting in step (a), a node of the first local area network by a self apparatus address and a node of the second local area network by a distant apparatus address.
Claim 20
Independent Claim
111 words
A method for communication between a first local area network and a second local area network, the second local area network being a ring-type local area network, said method comprising the steps of: (a) transmitting, to the second local area network, an internetwork transfer frame, the internetwork transfer frame defining at least a distant apparatus address; (b) storing the distant apparatus address of the internetwork transfer frame; (c) detecting the internetwork transfer frame after transmission around the second local area network; and (d) deleting the internetwork transfer frame when the distant apparatus address of the internetwork transfer frame received from the second local area network matches the stored distant apparatus address.
Claim 21
Independent Claim
111 words
A method for communication between a first local area network and a second local area network, the second local area network being a ring-type local area network, said method comprising the steps of: (a) transmitting, to the second local area network, an internetwork transfer frame, the internetwork transfer frame defining at least a distant apparatus address; (b) storing the distant apparatus address of the internetwork transfer frame; (c) detecting the internetwork transfer frame after transmission around the second local area network; and (d) deleting the internetwork transfer frame when the distant apparatus address of the internetwork transfer frame received from the second local area network matches the stored distant apparatus address.
Claim 22
Dependent Claim
48 words
A method as recited in claim 17, wherein said step of transmitting data in the internetwork transfer frame further defines a node of the first local area network by a self apparatus address and defines a node of the second local area network by the distant apparatus address.
Claim 23
Dependent Claim
36 words
A method as recited in claim 17, further comprising the step of (e) assigning, to each of the at least one stored frame, a flag indicating transfer frames that have been transmitted and not yet received.
Claim 24
Dependent Claim
48 words
A method as recited in claim 19, further comprising the step of (f) comparing a received internetwork transfer frame with the at least one stored frame to recognize a match when the flag therein indicates that the transfer frame corresponding thereto has been transmitted and not yet received.
References Cited (Backward Citations)
No citation records indexed.
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