EP0544452A2
Expired / Lapsed
EP
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Packet switching networks
Assignee: Cray Communications Ltd
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Filing: 1992-11-19
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Granted: —
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Expires: 2012-11-19
Abstract
Abstract A system in which core information, for example in the form of a core block or blocks (C), is transmitted in a core packet (PC), and at least some enhancement information, for example, in the form of enhancement blocks (E), is transmitted in an enhancement packet (PE) which is separate from the core packet (PC) and is discardable to relieve congestion. Preferably, the core and enhancement packets have headers (H) which include a discard eligible marker (DE) to indicate whether or not the associated packet can be discarded. The enhancement blocks (E) may be distributed between the core packet and enhancement packet in accordance with congestion conditions, or the enhancement blocks may be incorporated only in the enhancement packet, and the actual number of enhancement blocks included are varied depending on congestion conditions.
Inventors
- 👤 Jason Barry Brent
- 👤 Edward Hatala
- 👤 John Timms
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-01 05:23
CPC Classifications
H; H04; H04Q; H04Q11/00; H04Q11/04; H04Q11/0428; H04Q11/0478; H04L; H04L12/00; H04L12/54; H04L12/56; H04L12/5601; H04L12/5602; H04L49/00; H04L49/20; H04L49/205; H04L49/206; H04L49/50; H04L49/505; H04L2012/5614; H04L2012/5616; H04L2012/5629; H04L2012/5631; H04L2012/5632; H04L2012/5635; H04L2012/5636; H04L2012/5638; H04L2012/5646; H04L2012/5651; H04L2012/5652; H04L49/30; H04L49/501
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
80 words
A method of controlling congestion in a packet transmission system in which information to be transmitted is formatted into blocks according to whether it is core information or enhancement information so that the enhancement information can be discarded to relieve congestion, characterised in that the core information is transmitted in a core packet and at least some of the enhancement information is transmitted in an enhancement packet which is separate from the core packet and is discardable to relieve congestion.
Claim 2
Dependent Claim
18 words
A method as claimed in claim 1 in which the enhancement packet includes all of the enhancement information.
Claim 3
Dependent Claim
24 words
A method as claimed in claim 2 in which the amount of enhancement information included in the enhancement packet is reduced under congestion conditions.
Claim 4
Dependent Claim
41 words
A method as claimed in claim 1 in which each core packet further includes some enhancement information under conditions of non-congestion, at least some of said enhancement information being transferred from the core packet to the enhancement packet under congestion conditions.
Claim 5
Dependent Claim
37 words
A method as claimed in claim 1 in which each core packet further includes some enhancement information under conditions of non-congestion, at least some of said enhancement information being discarded from the core packet under congestion conditions.
Claim 6
Dependent Claim
23 words
A method as claim in claim 1 in which each packet has an indicator field which indicates whether or not it is discardable.
Claim 7
Dependent Claim
29 words
A method as claimed in claim 1 in which the packets are transmitted in a frame relay format with a standard header for all packets and variable length frames.
Claim 8
Dependent Claim
29 words
A method as claimed in claim 1 in which the packet transmission system is a packet switching network comprising a plurality of nodes each of which can experience congestion.
Claim 9
Dependent Claim
100 words
Apparatus for controlling congestion in a packet transmission system comprising encoder means which formats information to be transmitted into blocks according to whether it is core information or enhancement information so that the enhancement information can be discarded to relieve congestion, and packet assembler means which assembles said blocks into packets, characterised in that said packet assembler assembles the core information into a core packet and assembles at least some of the enhancement information into an enhancement packet which is separate from the core packet and is marked with a marker to indicate that it is discardable to relieve congestion.
Claim 10
Dependent Claim
48 words
Apparatus as claimed in claim 9 which includes means to monitor congestion conditions in the packet transmission system and which controls the packet assembler to transfer enhancement information, which is in the core packet under non-congestion conditions, from the core packet to the enhancement packet under congestion conditions.
Claim 11
Dependent Claim
47 words
Apparatus as claimed in claim 9 which includes means to monitor congestion conditions in the packet transmission system and which controls the packet assembler so that enhancement information, which is assembled into enhancement packets only, is reduced under congestion conditions so as to shorten the enhancement packet.
Claim 12
Dependent Claim
22 words
Apparatus as claimed in claim 9 including a packet switching network to which the packets are transmitted by the packet assembler means.
References Cited (Backward Citations)
No citation records indexed.
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