Control of access through local carrier sensing for high data rate networks and control of access of synchronous messages through circulating reservation packets

• US 5,229,993 A
• Filed: 02/25/1991
• Issued: 07/20/1993
• Est. Priority Date: 02/25/1991
• Status: Expired due to Fees

• Current Assignee: Old Dominion University (Commonwealth of Virginia)
• Original Assignee: Old Dominion University (Commonwealth of Virginia), The Center For Innovative Technology
• Inventors: Khanna, Sanjay, Foudriat, Edwin, Paterra, Frank, Maly, Kurt, Overstreet, C. M.
• Primary Examiner(s): Olms, Douglas W.
• Assistant Examiner(s): MARCELO, MELVIN C
• Application Number:
  US07/660,664
• Time in Patent Office: 876 Days
• Field of Search: 370/61, 370/85.2, 370/85.3, 370/85.4, 370/85.5, 370/85.15, 370/94.1, 370/94.2, 340/825.05
• US Class Current: 370/445
• CPC Class Codes: H04L 12/2852 Metropolitan area networks
• CPC Class Codes: H04L 12/433 with asynchronous transmission, e.g. token ring, register insertion
• CPC Class Codes: H04L 12/6418 Hybrid transport
• CPC Class Codes: H04L 2012/6448 Medium Access Control [MAC]
• CPC Class Codes: H04Q 11/0066 Provisions for optical burst or packet networks
• CPC Class Codes: H04Q 2011/0033 using time division switching
• CPC Class Codes: H04Q 2011/0064 Arbitration, scheduling or medium access control aspects

Abstract

A combination of two new access methods for ring and unidirectional bus networks supports high data rate integrated traffic. The first access method provides access for asynchronous traffic. When a node senses the channel idle, it can begin to transmit. When it senses an incoming signal, it must stop transmitting in order to avoid a collision. But unlike other access protocols which abort the transmission when a collision occurs or is imminent, the process truncates the message in a fashion such that it can be resumed later when the channel again is idle. The system is called Carrier Sensed Multiple Access-Ring Network (CSMA/RN). The second access method provides support for synchronous traffic. This method implements one or more circulating reservation packets which permit a node to have reserved space when the special packet returns. The media access system is called Circulating Reservation Packet (CRP) system. Both access protocols operate simultaneously on the network with minimal interference. The CRP system is preferably used with the CSMA/RN protocol but is applicable to other fixed length, non-corrupting, circulating network structures to enable the nodes in a network to reserve space for synchronous traffic and guaranteed access.

Claims

1. In a ring or unidirectional bus network having a plurality of nodes to which are connected a plurality of computer stations, a method for efficiently transmitting data on said network allowing multiple messages on the network simultaneously, said method being performed by control logic at each of said nodes and comprising the steps of:

sensing a carrier on said network to detect the presence of incoming data at the node;

if the incoming data is addressed to the node, receiving the data and removing it from said network;

if the data is not addressed to the node, retransmitting the data with fixed delay;

if the node is transmitting data at the time of receipt of incoming data and the incoming data is not addressed to the node, truncating the data being transmitted and retransmitting the incoming data;

if transmitting data at the time of receipt of incoming data addressed to the node, continuing to transmit data while receiving data.

2. The method recited in claim 1 wherein data transmitted on said network is transmitted in a packet including destination and source addresses further comprising the step of checking incoming data for the node'"'"'s own source address and removing said data from said network.

3. In a ring or unidirectional bus network comprising a plurality of nodes to which are connected a plurality of computer stations, a method for efficiently transmitting both synchronous and asynchronous data on said network, said method comprising the steps of:

circulating a plurality of circulating reservation packets on said network;

using a predetermined protocol, accessing by control logic at each of the nodes said network to transmit asynchronous data;

when synchronous data is to be transmitted by a respective one of said nodes, setting by the node a flag and space required in one of said circulating reservation packets to reserve space behind said one of said circulating reservation packets for said synchronous data; and

upon return to the one said node of said one of said circulating reservation packets, resetting said flag and transmitting said synchronous data in space reserved behind said one of said circulating reservation packets.

4. In a ring or unidirectional bus network having a plurality of nodes to which are connected a plurality of computer stations, a method for efficiently transmitting both asynchronous and synchronous data on said network allowing multiple messages on the network simultaneously, said method comprising the steps of:

circulating at least one circulating reservation packet on said network;

when synchronous data is to be transmitted by a respective one of said nodes, setting by the node a flag in said circulating reservation packet to reserve space behind said circulating reservation packet for said synchronous data;

upon return to said one node of said circulating reservation packet, resetting said flag and transmitting said synchronous data in space reserved behind said circulating reservation packet;

sensing by control logic at each node a carrier on said network to detect the presence of incoming data to the node;

if the incoming data is addressed to the node, receiving the data and removing it from said network by said node;

if the data is not addressed to the node, retransmitting by said node the data with fixed delay;

if the node is transmitting asynchronous data at the time of receipt of incoming data and the incoming data is not addressed to the node, truncating the asynchronous data being transmitted and retransmitting the incoming data; and

if transmitting data at the time of receipt of incoming data addressed to the node, continuing to transmit data while receiving data.

5. The method recited in claim 4 wherein data transmitted on said network is transmitted in a packet including destination and source addresses further comprising the step of checking incoming data for the node'"'"'s own source address and removing said data from said network.

6. The method recited in claim 5 wherein a plurality of circulating reservation packets are made to circulate on said network.

7. A ring or unidirectional bus network having a plurality of nodes to which are connected a plurality of computer stations, a control logic at each of said nodes for efficiently transmitting data on said network allowing multiple messages on the network simultaneously, said control logic at each of said nodes and comprising:

means for sensing a carrier on said network to detect the presence of incoming data to the node;

means for receiving the data at the node and removing it from said network if the incoming data is addressed to the node;

means for retransmitting the data with fixed delay if the data is not addressed to the node;

means for truncating the data being transmitted and retransmitting the incoming data if the node is transmitting data at the time of receipt of incoming data and the incoming data is not addressed the node;

means for continuing to transmit data while receiving data if transmitting data at the time of receipt of incoming data addressed to the node.

8. The network recited in claim 7 wherein data transmitted on said network is transmitted in a packet including destination and source addresses further comprising means for checking incoming data for the node'"'"'s own source address and removing said data from said network.

9. A ring or unidirectional bus network comprising a plurality of nodes to which are connected a plurality of computer stations, control logic at each of said nodes for efficiently transmitting both synchronous and asynchronous data on said network, said control logic comprising:

means for circulating a plurality of circulating reservation packets on said network;

means for accessing said network to transmit asynchronous data using a predetermined protocol;

means for setting a flag and space required in one of said circulating reservation packets to reserve space behind said one of said circulating reservation packets for said synchronous data when synchronous data is to be transmitted by a respective one of said nodes; and

means for resetting said flag and transmitting said synchronous data in space reserved behind said one of said circulating reservation packets upon return to the one said node of said one of said circulating reservation packets.

10. A ring or unidirectional bus network having a plurality of nodes to which are connected a plurality of computer stations, control logic at each of said nodes for efficiently transmitting both asynchronous and synchronous data on said network allowing multiple messages on the network simultaneously, said control logic comprising:

means for circulating at least one circulating reservation packet on said network;

means for setting by a node a flag in said circulating reservation packet to reserve space behind said circulating reservation packet for said synchronous data when synchronous data is to be transmitted by a respective one of said nodes;

means for resetting said flag and transmitting said synchronous data in space reserved behind said circulating reservation packet upon return to said node of said circulating reservation packet;

means for sensing a carrier on said network to detect the presence of incoming data to the node;

means for transmitting asynchronous data on said network if no incoming data is sensed;

means for receiving the data and removing it from said network by said node if the incoming data is addressed to the node;

means for retransmitting by said node the data with fixed delay if the data is not addressed to the node;

means for truncating the asynchronous data being transmitted and retransmitting the incoming data if the node is transmitting asynchronous data at the time of receipt of incoming data and the incoming data is not addressed to the node; and

said means for transmitting continuing to transmit data while receiving data if transmitting data at the time of receipt of incoming data addressed to the node.

11. The network recited in claim 10 wherein data transmitted on said network is transmitted in a packet including destination and source addresses further comprising means for checking incoming data for the node'"'"'s own source address and removing said data from said network.

12. The network recited in claim 11 wherein a plurality of circulating reservation packets are made to circulate on said network.