EP0576122A2
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EP
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Packet network and method for congestion avoidance in packet networks
Assignee: NTT Inc
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Filing: 1993-04-26
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Granted: —
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Expires: 2013-04-26
Abstract
Abstract A packet network comprises source nodes (3,30,40), destination nodes (3,30,40) and intermediate nodes (2,20). Sending and receiving of packets is carried out between source nodes (3,30,40) and destination nodes (3,30,40) via intermediate nodes (2,20), and an upper limit is established for the packet transfer rate that is permissible at the aforementioned source nodes. An upper limit is set for the value that indicates the degree of increase in the packet transfer rate of the aforementioned source nodes (3,30,40).
Inventors
- 👤 Nobuyuki Tokura
- 👤 Yoshio Kajiyama
- 👤 Hideo Tatsuno
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-25 08:12
CPC Classifications
H; H04; H04L; H04L12/00; H04L12/54; H04L12/56; H04L12/5601; H04L12/5602; H04L2012/5629; H04L2012/5631; H04L2012/5636
Claims Analysis
Total Claims: 29
Claim 1
Independent Claim
82 words
A packet network comprising source nodes (3,30,40), destination nodes (3,30,40) and intermediate nodes (2,20), wherein sending and receiving of packets is carried out between source nodes (3,30,40) and destination nodes (3,30,40) via intermediate nodes (2,20), and an upper limit is established for the packet transfer rate that is permissible at the aforementioned source nodes, characterised in that an upper limit is set for the value that indicates the degree of increase in the packet transfer rate of the aforementioned source nodes (3,30,40).
Claim 2
Dependent Claim
36 words
A packet network according to claim 1, and wherein the value indicating the degree of increase in packet transfer is the rate of change with time (hereafter, referred to as the acceleration) in packet transfer rate.
Claim 3
Dependent Claim
38 words
A packet network according to claim 1, and wherein the value indicating the degree of increase in packet transfer rate is the ratio of change with time (hereinafter, referred to as the acceleration ratio) in packet transfer rate.
Claim 4
Dependent Claim
36 words
A packet network according to any of claims 1 to 3, and wherein a lower limit or an initial rate is established for the packet transfer rate of the source nodes (3,30,40) in the packet network.
Claim 5
Dependent Claim
72 words
A packet network according to any of claims 1 to 4, and wherein the intermediate nodes (2,20) or destination nodes (3,30,40) in the packet network have means (53) for predicting packet transfer rate after time t on the basis of: the packet transfer rate of transit packets or the packet transfer rate of incoming packets; and the aforementioned upper limit for the value indicating the degree of increase in packet transfer rates.
Claim 6
Dependent Claim
34 words
A packet network according to claim 5, and wherein intermediate nodes (2,20) or destination nodes (3,30,40) have means (25) for predicting, on the basis of the predicted packet transfer rate, that congestion will occur.
Claim 7
Dependent Claim
35 words
A packet network according to claim 6, and wherein intermediate nodes (2,20) or destination nodes (3,30,40) have means (25) for notifying source nodes (3,30,40) of the congestion prediction, when the occurrence of congestion is predicted.
Claim 8
Dependent Claim
116 words
A congestion prediction circuit (25) for packet networks, characterised in that: it is provided in a packet network wherein, for each destination address or path identifier of packets or circuit identifier of packets that are to be transmitted through the transmission lines (11), an upper limit has been stipulated for the value indicating the degree of increase in packet transfer rate; and it has means (54) for detecting the packet transfer rate of currently arriving packets, and means (55) for predicting the maximum packet transfer rate after time t, on the basis of this detected packet transfer rate and the aforementioned upper limit stipulated for the value indicating the degree of increase in packet transfer rate.
Claim 9
Dependent Claim
53 words
A congestion prediction circuit for packet networks according to claim 8, and which has a means (54,55) whereby the maximum packet transfer rate V(t) after time t is obtained by calculation using: where α i (i=1∼m) is the stipulated upper limit for packet acceleration and V Σ is the total current packet rate.
Claim 10
Dependent Claim
87 words
A congestion prediction circuit for packet networks according to claim 8, and which has a means (56,55) whereby the maximum packet transfer rate V(t) after time t is obtained by calculation using: where exp(β) is the upper limit stipulated for packet acceleration ratio; and there is a lower limit for packet rate; and transmission lines are divided into n groups; and exp(β) (i=1∼n) is the maximum acceleration ratio within each group, and V G1 ∼ V Gn are the current packet transfer rates of the various groups.
Claim 11
Dependent Claim
98 words
A congestion prediction circuit for packet networks according to claim 8, and which has a means (56,55) whereby the maximum packet transfer rate V(t) after time t is obtained by calculation using: where exp(β) is the upper limit stipulated for packet acceleration ratio and VI j (j=1∼s) is the initial packet transfer rate; and the transmission lines (11) are divided into n groups; and exp(β) (i=1∼n) is the maximum acceleration within each group, V G1 ∼V Gn are the current packet transfer rates of the various groups, and: is the total of all the initial packet transfer rates.
Claim 12
Dependent Claim
122 words
A source node (3,30) for a packet network comprising source nodes (3,30,40) which send and receive packets to and from destination nodes (3,30,40) via intermediate nodes (2,20), and which have an upper limit for the permissible packet transfer rate of packets that they transmit: the source node (3,30) comprising; means (35) for transmitting packets at transfer rates which are within the aforementioned upper limit for packet transfer rates, and which correspond to a value that indicates the degree of increase in packet transfer rate up to a prescribed value; and means (38,39) for decreasing packet transfer rate when a congestion prediction signal to the effect that congestion will occur, is received from either an intermediate node (2,20) or a destination node (3,30,40).
Claim 13
Dependent Claim
123 words
A source node (40) for a packet network comprising source nodes (3,30,40) which send and receive packets to and from destination nodes (3,30,40) via intermediate nodes (2,20); and which have an upper limit for the permissible packet transfer rate of packets that they transmit: the source node (40) comprising; means (45) for transmitting packets at transfer rates which are within the aforementioned upper limit for packet transfer rates, and which correspond to a value that indicates the degree of increase in packet transfer rate up to a prescribed value; and means whereby packet transfer rate is not decreased even when a congestion prediction signal to the effect that congestion will occur is received from an intermediate node (20) or a destination node (3,30,40).
Claim 14
Dependent Claim
131 words
A source node (3,30,40) which sends and receives packets to and from destination nodes (3,30,40) via intermediate nodes (2,20): the source node (3,30,40) comprising; means (35,45) for transmitting packets at transfer rates corresponding to a value that indicates the degree of increase in packet transfer rate up to a prescribed value; and means (45,38,39) whereby, at transfer rates below a stipulated value, packet transfer rate is not decreased even if a congestion prediction signal to the effect that congestion is predicted, is received from an intermediate node (2,20) or a destination node (3,30,40); and at transfer rates above the aforementioned stipulated value, packet transfer rate is decreased if a congestion prediction signal to the effect that congestion is predicted, is received from an intermediate node (2,20) or a destination node (3,30,40).
Claim 15
Dependent Claim
79 words
A source node (3,30) according to claim 12 or 14, and having a means (38,39) whereby, instead of the arrival of a congestion prediction signal when congestion is predicted, packet transfer rate is decreased by the non-arrival at the source node (3,30) of new packets or user packets sent from a destination node (3,30,40) to the source node (3,30)when a rise in receiving rate has been accepted, said packets indicating a packet transfer rate increase request to this effect.
Claim 16
Dependent Claim
85 words
A source node (3,30) according to claim 12 or 14 or 15, and having a means (38,39) whereby, when a congestion prediction signal is received, packets are transmitted at a transfer interval which is a multiple k (k>1) times the packet transfer interval corresponding to the packet transfer rate at that point in time; or at a rate obtained by decreasing the packet transfer rate at that point in time by a fixed rate, or by a fixed ratio, or by a constant exponential ratio.
Claim 17
Dependent Claim
38 words
A source node (3,30) according to claim 12 or in any of claims 14-16, and which has a packet transmission control circuit (35) which decreases the packet transfer rate on the basis of a received congestion prediction signal.
Claim 18
Dependent Claim
53 words
A source node (3,30,40) according to any of claims 12-17, and which has a packet transmission interval rate with elapsed time as the address for each packet period, and where the packet transmission interval becomes shorter exponentially; and which also has a packet transmission control circuit (35) which forwards packets using this table.
Claim 19
Dependent Claim
60 words
A source node (3,30) according to claim 18, and which has a packet transmission control circuit (35) which, when packet transfer rate rises to a stipulated packet transfer rate, returns to an elapsed time address corresponding to this stipulated packet transfer rate, and which then carries out packet transmission by resuming use of the packet transmission intervals in the table.
Claim 20
Dependent Claim
58 words
A source node (3,30) according to claim 18 or 19, and which has a packet transmission control circuit (35) which forwards packets by returning, when a congestion prediction signal is received from the network, to an address which has been decreased by a fixed number or a fixed ratio from the aforementioned elapsed time address in the table.
Claim 21
Independent Claim
190 words
A method of congestion avoidance in packet networks wherein sending and receiving of packets is carried out between source nodes (3,30,40) and destination (3,30,40) nodes via intermediate nodes (2,20), and wherein an upper limit is established for the packet transfer rate that is permissable at the aforementioned source nodes (3,30,40) characterised in that; said source nodes (3,30,40) forward packets within the range of the permissible packet transfer rates, and within the range of the upper limit for a value that indicates the degree of increase in packet transfer rate; said intermediate nodes (2,20) or destination nodes (3,30,40) predict the packet transfer rate after time t on the basis of the packet transfer rate of transit packets or the packet transfer rate of incoming packets, and also on the basis of the aforementioned upper limit for the value that indicates the degree of increase in packet transfer rate, and, when congestion is predicted, notify the aforementioned source nodes (3,30,40) that congestion is anticipated; and when this notification to the effect that congestion is expected is received, the aforementioned source nodes (3,30,40) decrease the packet transfer rate at that point in time.
Claim 22
Dependent Claim
163 words
An integrated network wherein: sending and receiving packets is carried out between source nodes (3,30,40) and destination nodes (3,30,40) by way of intermediate nodes (2,20); an upper limit is established for the packet transfer rate of all source nodes; source nodes include source nodes (30) which decrease the packet transfer rate and source nodes (40) which do not decrease the packet transfer rate, upon receiving notification that congestion is anticipated; and also source nodes (30,40) which decrease the packet transfer rate during transmission at above a stipulated rate, but which do not decrease the packet transfer rate during transmission at below the stipulated rate: and wherein a congestion avoidance method for integrated packet networks is provided, wherein the size of the decrease in rate at source nodes (30) which decrease their packet transfer rate when notification is received that congestion is anticipated, takes into account the predicted rise in rate associated with the inclusion of source nodes (40) that do not decrease rate.
Claim 23
Dependent Claim
30 words
A congestion avoidance method for packet networks according to claim 21 or 22, and wherein the value that indicates the degree of increase in packet transfer rate is an acceleration.
Claim 24
Dependent Claim
30 words
A congestion avoidance method for packet networks according to claim 21 or 22, and wherein the value that indicates the degree of increase in packet transfer is an acceleration ratio.
Claim 25
Dependent Claim
32 words
A congestion avoidance method for packet networks according to any of claims 21-24, and wherein packet transfer rate is decreased by a fixed value when notification is received that congestion is predicted.
Claim 26
Dependent Claim
32 words
A congestion avoidance method for packet networks according to any of claims 21-24, and wherein packet transfer rate is decreased by a fixed ratio when notification is received that congestion is predicted.
Claim 27
Dependent Claim
31 words
A congestion avoidance for packet networks according to any of claims 21-24 and wherein packet transfer is decreased by a constant exponential ratio when notification is received that congestion will occur.
Claim 28
Dependent Claim
45 words
A congestion avoidance method for packet networks according to any of claims 21-27, and wherein notification that congestion will occur is carried out by not transmitting to the source nodes a packet transfer rate increase request signal or a packet transfer rate increase request indication.
Claim 29
Dependent Claim
34 words
A congestion avoidance method for packet networks according to any of claims 23-28, and wherein a lower limit or an initial rate is established for the packet transfer rate of the source nodes (3,30,40).
References Cited (Backward Citations)
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