US 4,538,147 A · Bandwidth allocation in a token controlled loop communications network

Abstract

A method of allocating available bandwidth between stations configured in a write token controlled loop communications network. When a station desires to reserve additional bandwidth to itself, it captures the write token and transmits a bandwidth allocation token which includes a field indicating the originating station's amount of currently reserved bandwidth. Each station on the loop adds to the field the amount of its currently reserved bandwidth. When the allocation token arrives back at the originating station, the write token is regenerated and transmitted. If the total amount of currently reserved bandwidth indicated in the allocation token plus the desired additional bandwidth sought to be reserved is less than the allocatable bandwidth, then the reservation is granted. The additional bandwidth desired is then added to the total reserved by the originating station.

Claims20

Dependent claims

A method of allocating bandwidth in a logical loop communications network, said network including a bus connected set of stations on a broadcast medium wherein a logical ordering of said stations is enforced by passing a write token from one of said stations to another in a predictable order with the last station in the order passing the write token to the first station in the order, each of said stations having associated with it at least one identifier address, said method comprising the steps of:

allocating to a number of said stations a portion of the bandwidth available on said logical loop;
and
reserving for each one of said number of said stations that desires to reserve bandwidth for itself a portion of the allocated bandwidth, wherein the sum of the portions of the allocated bandwidth reserved by all of said number of said stations does not exceed the allocated bandwidth.

The method in accordance with claim 2 wherein one of said number of said stations desiring to reserve an additional portion of the allocated bandwidth performs the following steps:

that one of said number of said stations captures the write token;
that one of said number of said stations generates a bandwidth allocation token, the generated bandwidth allocation token including first and second information fields specifying the identifier address of that one of said number of said stations and the portion of the allocated bandwidth currently reserved by that one of said number of said stations, respectively;
and
that one of said number of said stations transmits the generated bandwidth allocation token onto the logical loop.

1 more element

A method of allocating bandwidth in a loop communications network, said network including a loop-connected set of stations providing data flow unidirectionally from one of said stations to the next, each of said stations having associated with it at least one identifier address, the right of each of said stations to source new data onto the network controlled by passing a write token from one of said stations to another, said method comprising the steps of:

allocating to a number of said stations a portion of the bandwidth available on said loop;
and
reserving for each one of said number of said stations that desires to reserve bandwidth for itself a portion of the allocated bandwidth, wherein the sum of the portions of the allocated bandwidth reserved by all of said number of said stations does not exceed the allocated bandwidth.

A method of allocating bandwidth in a loop communications network, said network including a loop-connected set of stations providing data flow unidirectionally from one of said stations to the next, each of said stations having associated with it at least one identifier address, a number of said stations being of a Class 1 priority, the right of each of said stations to source new data into the network controlled by passing a write token from one of said stations to another, said method comprising the steps of:

allocating to the number of said stations including all of said Class 1 priority stations a first portion (ALLOC) of the bandwidth available on said loop;
and
reserving for each one of said Class 1 stations that desires to reserve bandwidth for itself a portion of the ALLOC bandwidth, the reservation of portions of the ALLOC bandwidth done in accordance with a bandwidth allocation procedure, wherein the sum of the ALLOC bandwidth reserved by all of said Class 1 stations does not exceed the ALLOC bandwidth, and wherein one of said Class 1 stations desiring to reserve and additional amount of the ALLOC bandwidth performs the following steps:
that one of said Class 1 stations captures the write token;
that one of said Class 1 stations generates a bandwidth allocation token, the generated bandwidth allocation token including first and second information fields specifying the identifier address of that one of said Class 1 stations and the amount of the ALLOC bandwidth currently reserved by that one of said Class 1 stations, respectively;
and
that one of said Class 1 stations transmits the generated bandwidth allocation token onto the loop.

4 more elements

Dependencies are inferred from the claim text.

Bandwidth allocation in a token controlled loop communications network

Life of this patent

Bandwidth allocation in a token controlled loop communications network

Life of this patent

Abstract

Claims20