Patent EP0625838A2 successfully refreshed from Google Patents.
EP0625838A2
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EP
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Token ring network
Assignee: International Business Machines Corp
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Filing: 1994-01-31
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Granted: —
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Expires: 2014-01-31
Abstract
Abstract A token ring local area network includes workstations running both conventional data and multimedia applications. The latter, which generally require a minimum throughput in order to be viable, can be split into two further categories: those which cannot tolerate excessive latency (end to end delay), typically interactive applications such as voice communications, and those which are less sensitive to latency, typically playback operations. the network recognises three priority levels: (1) for latency-sensitive multimedia applications, (2) for latency-insensitive multimedia applications, and (3) conventional applications. All multimedia applications prior to commencement of any communications over the LAN must request an allocation of throughput from a LAN segment resource manager (LSRM), which will only be awarded if there is currently sufficient available throughput on the LAN to support the attended communication. Furthermore, first priority level applications are also given a maximum token holding time, thereby ensuring rapid circulation of the token, and controlling latency.
Inventors
- 👤 Peter Cripps
- 👤 Keith Barraclough
- 👤 Adrian Gay
- 👤 Alan Jones
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-06 13:08
CPC Classifications
H; H04; H04L; H04L12/00; H04L12/28; H04L12/42; H04L12/427; H04L12/433
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
222 words
A method of operating a token ring local area network, in which a plurality of nodes are arranged in a ring configuration, a node communicating by sending a transmission over the network when it has control of the token, the network supporting at least three priority levels of communication, designated first, second and third in decreasing order of importance, the network including a LAN segment resource manager (LSRM) for maintaining information about the first and second priority level communications currently in progress, the method including the steps of: assigning maximum throughput allocations to the three priority levels, and storing said allocations in the LSRM; sending a request from a node to the LSRM for permission to commence a first or second priority level communication, together with the desired throughput allocation; determining at the LSRM whether or not to award the requesting node the desired throughput allocation, dependent on the currently available throughput, and responding accordingly to the requesting node; determining at the LSRM, for first priority level communications, the maximum time for which the requesting node can retain control of the token for a single transmission before release of the token, and responding accordingly to the requesting node; recording at the LSRM any new allocation of throughput; and commencing communications at the requesting node in accordance with the response from the LSRM.
Claim 2
Dependent Claim
32 words
The method of claim 1, further comprising the step of sending a notification from a node to the LSRM when any first or second priority level communication for that node has completed.
Claim 3
Dependent Claim
39 words
The method of claim 1 or 2, further comprising the steps of the LSRM monitoring communications on the token ring, and comparing the results with the recorded throughput allocations to verify that nodes are adhering to their throughput allocations.
Claim 4
Independent Claim
51 words
The method of any preceding claim, further comprising the step of any node supporting first and/or second priority level communications in addition to third priority level communications maintaining two queues of data to be transmitted, one for first and/or second priority level communications, and the other for third priority level communications.
Claim 5
Independent Claim
25 words
The method of any preceding claim, wherein the LSRM reserves at least a certain portion of the total available throughput for priority level three communications.
Claim 6
Independent Claim
70 words
The method of any preceding claim, wherein each node transmitting first and/or second priority level communications includes a local segment access agent (LSAA) performing the steps of: assigning an identifier to each application at the node that has been granted a throughput allocation for first or second priority level communications; and monitoring outgoing first or second priority level communications to verify that they are associated with a correctly assigned identifier.
Claim 7
Dependent Claim
41 words
The method of claim 6, wherein the LSAA further performs the step of monitoring outgoing first priority level communications to ensure that any application at the node makes only one first priority level transmission within a predetermined maximum network latency period.
Claim 8
Dependent Claim
227 words
Apparatus for operating a token ring local area network, in which a plurality of nodes are arranged in a ring configuration, a node communicating by sending a transmission over the network when it has control of the token, the network supporting at least three priority levels of communication, designated first, second and third in decreasing order of importance, the apparatus including: a LAN segment resource manager (LSRM) for maintaining information about the first and second priority level communications currently in progress, means for assigning maximum throughput allocations to the three priority levels, and storing said allocations in the LSRM; means for sending a request from a node to the LSRM for permission to commence a first or second priority level communication, together with the desired throughput allocation; means for determining at the LSRM whether or not to award the requesting node the desired throughput allocation, dependent on the currently available throughput, and responding accordingly to the requesting node; means for determining at the LSRM, for first priority level communications, the maximum time for which the requesting node can retain control of the token for a single transmission before release of the token, and responding accordingly to the requesting node; means for recording at the LSRM any new allocation of throughput; and means for commencing communications at the requesting node in accordance with the response from the LSRM.
References Cited (Backward Citations)
No citation records indexed.
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