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EP0717532A1 Expired / Lapsed EP ⏱️ 0.0 years remaining

Dynamic fair queuing to support best effort traffic in an ATM network

Assignee: International Business Machines Corp
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Filing: 1994-12-13
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Granted: —
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Expires: 2014-12-13
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Abstract

Abstract A traffic control apparatus implemented in a virtual path ATM communication system comprising a plurality of hops interconnected by physical links which comprise virtual paths including a plurality of virtual channels. A connection between two hops is defined as the combination of a physical link, a virtual path, and a virtual channel. Said connections are shared between a reserved bandwidth service and a best effort service. ATM data cells conveyed on said best effort service are routed from hop to hop by analyzing their virtual connection identifier. This is done by managing a pool of free queues being able to store ATM data cells, each of said queues storing all the incoming ATM data cells having the same virtual channel identifier.

Inventors

  • 👤 Jean Calvignac
  • 👤 Fabrice Verplanken
  • 👤 Daniel Le Dauphin Bleu Orsatti

Bibliographic Details

Application Number —
Jurisdiction EP
Data Source google_patents
Last Synchronized 2026-11-06 17:14
CPC Classifications
H; H04; H04L; H04L12/00; H04L12/54; H04L12/56; H04L12/5601; H04L12/5602; H04L47/00; H04L47/10; H04L49/00; H04L49/30; H04L49/3081; H04L2012/5619; H04L2012/5629; H04L2012/5631; H04L2012/5632; H04L2012/5635; H04L2012/5678; H04L2012/5679

Claims Analysis

Total Claims: 10
Claim 1
Independent Claim 246 words
Traffic control apparatus implemented in a ATM communication system, said communication system comprising a plurality of hops (50) interconnected by links (501), each of said link defined by a link identifier comprising a plurality of virtual paths (503), each of said virtual path defined by a virtual path identifier VPi comprising a plurality of virtual channels (502), each of said channel being defined by a virtual channel identifier VCi, the combination of said identifiers defining a virtual connection, wherein said hops route incoming data cells (51) conveyed by a virtual connection to downstream hops, said data cells being identified by a virtual path identifier CVPi, and a virtual channel identifier CVCi, said routing being performed with regard to said virtual path identifier CVPi, said apparatus comprising at each hop (50): - identifying means (500) for identifying said CVPi and said CVCi for each incoming data cell (51), said apparatus being characterized in that it comprises managing means including : - a pool of free queues (510) for storing ATM data cells, and - means for leasing a queue (520), from said pool of free queues, corresponding to the virtual connection on which said incoming data cell is conveyed if said queue does not already exist, and queuing said incoming data cell into said leased queue, and - means for queuing (540) an incoming data cell in the queue corresponding to the virtual connection on which said incoming data cell is conveyed, if said queue already exists.
Claim 2
Dependent Claim 50 words
Traffic control apparatus according to claim 1, wherein said managing means comprise: - a round robin scheduler (560) for scheduling said queues, and - inserting means (570) for inserting a queue in said round robin scheduler, and - desinserting means (580) for desinserting said queue from said round robin scheduler
Claim 3
Dependent Claim 44 words
Traffic control apparatus according to claim 2, wherein said managing means comprise: - dequeuing means (550) for dequeuing a cell of a scheduled queue, and - means for releasing (530) said scheduled queue in said pool of free queues if said queue becomes empty.
Claim 4
Dependent Claim 36 words
Traffic control apparatus according to claim 2 or 3 wherein said managing means are able to stop routing data cells conveyed by a particular virtual connection in response to a first request from a downstream hop.
Claim 5
Dependent Claim 70 words
Traffic control apparatus according to claim 4, wherein in response to said first request : - if the queue corresponding to said particular virtual connection exists, said managing means desinsert said queue from said round robin scheduler (560), and - if the queue corresponding to said particular virtual connection does not exist, said managing means lease a queue from said pool of free queues (510), for said particular virtual connection.
Claim 6
Dependent Claim 37 words
Traffic control apparatus according to any of claims 2 to 5, wherein said managing means are able to restart routing data cells conveyed by a particular connection in response to a second request from a downstream hop.
Claim 7
Dependent Claim 66 words
Traffic control apparatus according to claim 6 therein in response to said second request : - if the queue corresponding to said particular virtual connection is not empty, said managing means insert said queue in said round robin scheduler (560), and - if the queue corresponding to said particular virtual connection is empty, said managing means release said queue in said pool of free queues (510)
Claim 8
Dependent Claim 86 words
Traffic control apparatus according to any of the preceding claims characterized in that said managing means of a hop comprise: - counting means (590) for counting the number of queues leased in said hop, and - a high threshold and a low threshold, said high threshold being greater than said low threshold and set so that the extra number of queues above said high threshold, in said pool of free queues, is greater than the aggregate round trip delay of the upstream hops of said hop.
Claim 9
Dependent Claim 57 words
Traffic control apparatus according to claim 8 characterized in that when the value of said counting means becomes greater than said high threshold and said upstream hops are not already backpressured, said hop sends backwards on each incoming link (501) to said upstream hops, a stop request, in order to stop the traffic from said entering links.
Claim 10
Dependent Claim 57 words
Traffic control apparatus according to claim 8 or 9 characterized in that when the value of said counting means becomes lower than said low threshold and said upstream hops are backpressured, said hop sends backwards on each incoming link (501) to said upstream hops, a restart request in order to restart the traffic from said entering links.

References Cited (Backward Citations)

EP0272939A2 Cited
EP0430570A2 Cited
US5231633A Cited

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