Patent US3862698A successfully refreshed from Google Patents.
EP0785652A1
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Variable band communication network
Assignee: NTT Inc
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Filing: 1996-07-02
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Granted: —
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Expires: 2016-07-02
Abstract
Abstract When bandwidth in an ATM network is controlled so as to increase in accordance with a user request, there is a considerable delay from the occurrence of the request until the bandwidth is actually changed, and there is therefore a need to control the traffic flowing in ATM network transmission paths faster and more flexibly. There is also a need to decrease the probability of overbooking occurring when deciding whether or not to accept a bandwidth change request. Route information that includes information relating to residual bandwidth is therefore collected in advance by subscriber switches that serve terminals. In response to a request from a user, a subscriber switch alone replies rapidly. During this process, account is taken of the fact that there are a plurality of bandwidth change requests within the same residual bandwidth measurement period, and a portion of the measured residual bandwidth is held for other bandwidth change requests. This enables the aforesaid delay to be shortened. In addition, it is sufficient if the functions corresponding to the plurality of protocols employed by users are provided at and only at the subscriber switches which directly serve those users, whereby the hardware configuration of the transit switches etc. can be simplified. In addition, bandwidth can be allocated with high precision.
Inventors
- 👤 Haruhisa Hasegawa
- 👤 Naoaki Yamanaka
- 👤 Kouhei Shiomoto
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-06 17:01
CPC Classifications
H; H04; H04L; H04L12/00; H04L12/54; H04L12/56; H04L12/5601; H04L12/5602; H04Q; H04Q11/00; H04Q11/04; H04Q11/0428; H04Q11/0478; H04L2012/5619; H04L2012/5629; H04L2012/5631; H04L2012/5632; H04L2012/5634; H04L2012/5635; H04L2012/5636
Claims Analysis
Total Claims: 25
Claim 1
Independent Claim
125 words
A variable-bandwidth network comprising a plurality of subscriber switches, a plurality of physical transmission paths that connect these plurality of subscriber switches with each other, and transit switches interposed among these plurality of physical transmission paths; wherein routes are set among the aforesaid plurality of subscriber switches; the aforesaid subscriber switches having means which supports the protocols by which users perform adaptive flow control between themselves and the network; said variable-bandwidth network being characterised in that a source-side subscriber switch comprises: means for collecting route information that includes information relating to the residual bandwidth of a route that has been set between said source-side subscriber switch and a destination-side subscriber switch; and means for performing the aforesaid flow control in accordance with this route information.
Claim 2
Dependent Claim
84 words
A variable-bandwidth network as set forth in Claim 1, wherein the aforesaid means which collects route information is provided in a source-side subscriber switch and includes means which outputs, to each aforesaid route, cells for the purpose of collecting the route information of said route, and wherein the aforesaid transit switches and subscriber switches have means which, when these cells have arrived, loads route information into their data field and forwards the cells in accordance with the routing information recorded in their address field.
Claim 3
Dependent Claim
43 words
A variable-bandwidth network as set forth in Claim 1, wherein the destination-side subscriber switch and the aforesaid transit switches have means for addressing and sending cells to a source-side subscriber switch, said cells bearing route information relating to VPs pertaining to these switches.
Claim 4
Dependent Claim
77 words
A variable-bandwidth network as set forth in Claim 1, wherein a centralised controller is provided in the network, and the aforesaid subscriber switches and transit switches have means for sending cells bearing the aforesaid route information, said cells being addressed to this centralised controller; said centralised controller comprising means for reading and collecting the route information from these cells that have arrived, and means for notifying the aforesaid subscriber switch of the contents of this collecting means.
Claim 5
Dependent Claim
45 words
A variable-bandwidth network as set forth in Claim 1, wherein the aforesaid sending means has means which, when congestion has occurred in a VP pertaining to its subscriber switch or its transit switch, sends cells bearing route information that includes information relating to this congestion.
Claim 6
Dependent Claim
75 words
A variable-bandwidth network as set forth in Claim 1, wherein an aforesaid subscriber switch includes a residual bandwidth table which stores information relating to the bandwidth utilisation of the aforesaid routes, and means which, when there has been a bandwidth change request from a terminal served by said subscriber switch, decides for or against the bandwidth change of that terminal by making a comparison with the residual bandwidth stored in the aforesaid residual bandwidth table.
Claim 7
Dependent Claim
46 words
A variable-bandwidth network as set forth in Claim 6, wherein the aforesaid subscriber switch includes means which monitors the minimum residual bandwidth on routes through which its connections pass, by periodically transferring operations and maintenance cells to the other subscriber switches connected via the aforesaid routes.
Claim 8
Dependent Claim
72 words
A variable-bandwidth network as set forth in Claim 6, wherein the aforesaid means which decides for or against a bandwidth change includes means which takes account of the fact that there are a plurality of bandwidth change requests in the same residual bandwidth measurement period, and which reserves a portion of the residual bandwidth of each route measured by the aforesaid measuring means, said portion being reserved for other bandwidth change requests.
Claim 9
Dependent Claim
46 words
A variable-bandwidth network as set forth in Claim 8, wherein the aforesaid reserving means includes means whereby a residual bandwidth measured by the aforesaid measuring means is multiplied by a preset safety factor for that route, and the result is taken as the allocatable residual bandwidth.
Claim 10
Dependent Claim
61 words
A variable-bandwidth network as set forth in Claim 8, wherein the aforesaid reserving means includes means whereby a residual bandwidth measured by the aforesaid measuring means is multiplied by a safety factor determined by the intervals at which bandwidth change requests for that route have occurred up to the present time, and the result is taken as the allocatable residual bandwidth.
Claim 11
Dependent Claim
40 words
A variable-bandwidth network as set forth in Claim 8, wherein the aforesaid reserving means includes means which obtains the allocatable residual bandwidth on the basis of the changes to date in the residual bandwidth measured by the aforesaid measuring means.
Claim 12
Dependent Claim
62 words
A variable-bandwidth network as set forth in Claim 8, wherein the aforesaid reserving means includes means which takes as the allocatable residual bandwidth the sum of (i) the value obtained by multiplying the residual bandwidth measured by the aforesaid measuring means the previous time by a smoothing coefficient α, and (ii) the value obtained by multiplying the newly-measured residual bandwidth by 1-α.
Claim 13
Dependent Claim
79 words
A variable-bandwidth network as set forth in Claim 1, wherein the aforesaid subscriber switch comprises means for collecting and recording new route information relating to a plurality of routes that can be set between a source-side subscriber switch and another subscriber switch which constitutes the destination-side subscriber switch, irrespective of whether there is a connection request; and means which, when there is a connection request, selects a route for that user on the basis of this recorded route information.
Claim 14
Dependent Claim
67 words
A variable-bandwidth network as set forth in Claim 13, wherein the aforesaid recording means includes means which sends to each route cells for the purpose of collecting route information, and the aforesaid transit switches and subscriber switches have means which, when these cells have arrived, loads route information into their data field and forwards the cells in accordance with the routing information recorded in their address field.
Claim 15
Dependent Claim
45 words
A variable-bandwidth network as set forth in Claim 14, wherein the aforesaid route information is information relating to VPs pertaining to the aforesaid transit switches and subscriber switches, and the aforesaid forwarding means forwards the aforesaid cells after addressing them to the source-side subscriber switch.
Claim 16
Dependent Claim
55 words
A variable-bandwidth network as set forth in Claim 13, wherein the aforesaid route selecting means selects, from among the aforesaid plurality of routes, and from among routes which have more residual bandwidth than the bandwidth requested by the user, the route with the least residual bandwidth or the route with the smallest residual bandwidth ratio.
Claim 17
Dependent Claim
52 words
A variable-bandwidth network as set forth in Claim 13, wherein the aforesaid route selecting means selects, from among the aforesaid plurality of routes, and from among routes which have more residual bandwidth than the bandwidth requested by the user, the route with the largest utilised bandwidth or the largest utilised bandwidth ratio.
Claim 18
Dependent Claim
75 words
A variable-bandwidth network as set forth in Claim 13, wherein a centralised controller is provided, and the aforesaid subscriber switches and transit switches have means which outputs cells bearing route information and addressed to this centralised controller, and the aforesaid centralised controller comprises means which reads and collects route information from these cells when they have arrived, and means which notifies the aforesaid subscriber switches of the content collected by this reading and collecting means.
Claim 19
Dependent Claim
44 words
A variable-bandwidth network as set forth in Claim 14, wherein, when congestion has occurred in a VP pertaining to its transit switch or its subscriber switch, the aforesaid means which outputs cells outputs cells bearing route information and containing information relating to that congestion.
Claim 20
Dependent Claim
66 words
A variable-bandwidth network as set forth in Claim 1, wherein the aforesaid subscriber switch has means which communicates congestion information to the terminals it serves, and this communicating means includes means which independently forms cells into which are written requests for increased or decreased cell rate, the allowed cell rate, and congestion information, and which transmits these cells to the terminals served by its subscriber switch.
Claim 21
Dependent Claim
141 words
A variable-bandwidth network as set forth in Claim 1, wherein each of the aforesaid subscriber switches and transit switches comprises: a table in which is recorded information relating to the allocated bandwidth (Bi, where i=1, ..., n) of routes pertaining to that switch, or of partial paths comprising VPs on those routes; means for calculating the allocatable bandwidth by referring to said table when there has been a setup request for a requested bandwidth (Ri) on a given route (the i th route) pertaining to that switch, or for a partial path comprising a VP on that route; means for reserving the result of this calculation in said table; and means which sets this reserved value as the new allocated bandwidth of the route in question (the i th route) or of the partial path comprising a VP on that route.
Claim 22
Dependent Claim
206 words
A variable-bandwidth network as set forth in Claim 21, wherein the aforesaid subscriber switch on the source side has: means which outputs a management packet already bearing the aforesaid requested bandwidth (R) to the route which it is desired to set up, or to the partial path comprising a VP on that route, said management packet being output prior to the use of that route or partial path comprising a VP on that route, and said outputting means recovering this management packet after it has passed through that route which it is desired to set up, or through the partial path comprising a VP on that route; and means which recognises, from this recovered management packet, the new allocated bandwidth for that route which it is desired to set up or for the partial path comprising a VP on that route; wherein, when this management packet arrives at each of the aforesaid subscriber switches and transit switches, the aforesaid requested bandwidth (R) which was loaded into this management packet at that source-side subscriber switch is given to the aforesaid calculating means as the requested bandwidth (Ri) of the route in question (the i th route) or of a partial path comprising a VP on that route.
Claim 23
Dependent Claim
86 words
A variable-bandwidth network as set forth in Claim 22, wherein each of the aforesaid subscriber switches and transit switches has: means which compares the aforesaid requested bandwidth (R) carried in the management packet which has arrived, and the new allocated bandwidth that was calculated by the aforesaid calculating means, and which reserves the smaller of these in the aforesaid table of the switch; and means which forwards that management packet after substituting the new allocated bandwidth reserved in this table for the aforesaid requested bandwidth (R).
Claim 24
Dependent Claim
72 words
A variable-bandwidth network as set forth in Claim 21, wherein the aforesaid calculating means includes calculating means which averages the weighting of the allocated bandwidth relative to the requested bandwidth by minimising the evaluation function: F(B)=(1/n)· i=1 to n Σ[(Bi/Ri)-(1/n)· i=1 to n Σ(Bj/Rj)] 2 where Bi is the allocated bandwidth, Ri is the requested bandwidth (i=1, 2, ..., n), and n is the number of routes multiplexed in an output VP.
Claim 25
Dependent Claim
24 words
An ATM network as set forth in Claim 21, wherein the new allocated bandwidth Bj is updated as follows: Bj←Bj-αj·(n·(Bj/Rj)- i=1 to n Σ(Bi/Ri))·((n-1)/Rj).
References Cited (Backward Citations)
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