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EP0600683A2 Expired / Lapsed EP ⏱️ 0.0 years remaining

Packet network interface

Assignee: AT&T Inc
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Filing: 1993-11-26
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Granted: —
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Expires: 2013-11-26
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Abstract

Abstract A packet switch interface (14), which may be an asynchronous transfer mode (ATM) layer interface chip, may be connected to the inputs or the outputs of a packet switch. The interface chip modifies the virtual parth and the virtual channel identifier in packets directed to and from the switch. The interface chip also manipulates routing tags for the packets which are used for internal routing purposes in the switch. The interface chip includes a local interface (42) through which packets may be extracted from or added to a packet stream flowing between a main input (11) and a main output (17) of the interface. The interface chip polices different communications channels handled in the interface chip by detecting whether traffic in those channels exceeds certain network usage parameters. The interface is also capable of gathering certain statistical information about the traffic in certain communications channels to allow evaluation of network performance. These operations are performed in hardware on a single integrated circuit chip involving a single table look up. This table look up involves addressing a content addressable memory (32) with a predetermined portion of the header of a packet. Finding a match between the predetermined portion of the packet header and the content of the content addressable memory causes the memory to produce an address signal which acts as a pointer to a location in a random address memory (34) containing a parameter block having data used to perform the operations of the interface.

Inventors

  • 👤 Vijay P Kumar
  • 👤 Horng-Dar Lin
  • 👤 Jay Henry O'neill
  • 👤 Philippe Oechslin
  • 👤 Edward Joseph Ouellette Iii

Bibliographic Details

Application Number —
Jurisdiction EP
Data Source google_patents
Last Synchronized 2026-11-02 08:28
CPC Classifications
H; H04; H04L; H04L49/00; H04L49/30; H04L49/3081; H04L49/309; H04L12/00; H04L12/54; H04L12/56; H04L12/5601; H04L49/3009; H04L49/50; H04L49/501; H04L49/503; H04Q; H04Q11/00; H04Q11/04; H04Q11/0428; H04Q11/0478; H04L2012/5619; H04L2012/5629; H04L2012/5631; H04L2012/5636; H04L2012/5638; H04L2012/5646; H04L2012/5652; H04L2012/5685; H04L49/25; H04L49/55; H04L49/555

Claims Analysis

Total Claims: 25
Claim 1
Independent Claim 50 words
A packet network interface, comprising: an input for receiving a packet; a content addressable memory responsive to a selectable and predetermined part of the packet for producing an address signal; and a random access memory responsive to the address signal for producing at least one parameter relating to the packet.
Claim 2
Dependent Claim 16 words
The interface of claim 1, in which the parameter comprises a new header for the packet.
Claim 3
Dependent Claim 16 words
The interface of claim 1, in which the parameter comprises a local header for the packet.
Claim 4
Dependent Claim 20 words
The interface of claim 1, in which the predetermined part of the packet comprises a header portion of the packet.
Claim 5
Dependent Claim 25 words
The interface of claim 4, in which the predetermined part of the packet comprises a virtual path identifier in the header portion of the packet.
Claim 6
Dependent Claim 26 words
The interface of claim 5, in which the predetermined part of the packet also comprises a virtual circuit identifier in the header portion of the packet.
Claim 7
Dependent Claim 41 words
The interface of claim 6, in which the parameter comprises a new virtual channel identifier and a new virtual path identifier to be substituted for the virtual path identifier and the virtual channel identifier in the header portion of the packet.
Claim 8
Dependent Claim 14 words
The interface of claim 1, in which the parameter comprises a network usage parameter.
Claim 9
Dependent Claim 15 words
The interface of claim 8, in which the usage parameter comprises a bandwidth usage parameter.
Claim 10
Dependent Claim 14 words
The interface of claim 8, in which the usage parameter is a burstiness parameter.
Claim 11
Dependent Claim 21 words
The interface of claim 8, further comprising: a means for determining if there has been a violation of the usage parameter.
Claim 12
Dependent Claim 20 words
The interface of claim 11, in which the means for determining comprises a means for effectuating a leaky bucket process.
Claim 13
Dependent Claim 48 words
The interface of claim 12, in which the effectuating means comprises: a means for defining a leak rate and a bucket size; and a means for determining a level of a bucket in response to the leak rate and an arrival of a packet received by the interface.
Claim 14
Dependent Claim 23 words
The interface of claim 11, further comprising: a means for dropping the packet in response to a violation of the network usage parameter.
Claim 15
Dependent Claim 25 words
The interface of claim 11, further comprising: a means of marking the packet as droppable in response to a violation of the network usage parameter.
Claim 16
Dependent Claim 25 words
The interface of claim 11, further comprising: a means for shaping traffic output from the interface in response to a violation of the usage parameter.
Claim 17
Dependent Claim 22 words
The interface of claim 1, further comprising: a means for modifying a predetermined part of the packet in response to the parameter.
Claim 18
Dependent Claim 26 words
The interface of claim 1, further comprising: a means for selecting a predetermined portion of the packet to determine a match in the content addressable memory.
Claim 19
Dependent Claim 14 words
The interface of claim 17, in which the modifying means comprises a modification mask.
Claim 20
Dependent Claim 14 words
The interface of claim 18, in which the selecting means is an identification mask.
Claim 21
Independent Claim 92 words
A method of interfacing communications paths to a packet switch in communications network, comprising the steps of: connecting an interface between a communications path and a packet switch in a network; receiving a packet in the interface; identifying in the interface a predetermined portion of the packet received by the interface representing a virtual circuit to which the packet belongs; modifying a predetermined portion of the packet in the interface; detecting in the interface if the packet violates a network usage parameter; and directing the packet to an output of the interface.
Claim 22
Dependent Claim 43 words
The method of claim 21, further comprising the step of: detecting routing information in the packet; and selectively directing the packet to one of a main output of the interface and a local output of the interface in response to the detecting step.
Claim 23
Independent Claim 88 words
A method of interfacing communications paths to a packet switch in a communications network, comprising the steps of: connecting an interface between a communications path and a packet switch in a communications network; receiving a packet in the interface; identifying in the interface a predetermined portion of the packet received by the interface; gathering statistical information in the interface about a communications channel to which the packet belongs in response to the identification step; and directing the packet to an output of the interface after the gathering step.
Claim 24
Dependent Claim 33 words
The method of claim 23, further comprising the step of: determining a number of packets which have been lost by the communications network in response to the statistical information gathered by the interface.
Claim 25
Dependent Claim 27 words
The method of claim 24, further comprising the step of: determining, in response to the statistical information, a location in the network where packets have been lost.

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