MONITORING NETWORKS

• US 20090279433A1
• Filed: 06/26/2007
• Published: 11/12/2009
• Est. Priority Date: 06/26/2006
• Status: Active Grant

• Current Assignee: British Telecommunications PLC (BT Group PLC)
• Original Assignee: British Telecommunications PLC (BT Group PLC)
• Inventors: Briscoe, Robert J., Jacquet, Arnaud
• Granted Patent: US 8,259,578 B2
• Time in Patent Office: Days
• US Class Current: 370/235
• CPC Class Codes: H04L 43/00 Arrangements for monitoring or testing data switching networks
• CPC Class Codes: H04L 43/022 by sampling
• CPC Class Codes: H04L 43/026 using flow identification
• CPC Class Codes: H04L 43/16 Threshold monitoring
• CPC Class Codes: H04L 47/10 Flow control; Congestion control
• CPC Class Codes: H04L 47/11 Identifying congestion
• CPC Class Codes: H04L 47/12 Avoiding congestion; Recovering from congestion
• CPC Class Codes: H04L 47/18 End to end
• CPC Class Codes: H04L 47/22 Traffic shaping
• CPC Class Codes: H04L 47/26 using explicit feedback to the source, e.g. choke packets
• CPC Class Codes: H04L 47/28 in relation to timing considerations
• CPC Class Codes: H04L 47/32 by discarding or delaying data units, e.g. packets or frames
• CPC Class Codes: H04L 47/35 by embedding flow control information in regular packets, e.g. piggybacking

Abstract

Methods and systems for determining a correction factor for use in monitoring network traffic, said network traffic comprising a plurality of flows of data units, each flow having associated therewith a flow identifier, said data units having associated therewith a path characterisation metric; the method comprising the steps of: selecting a subset of flow identifiers from the overall set of flow identifiers; determining, in respect of flows having associated therewith flow identifiers from said selected subset of flow identifiers, which flows if any are persistently irregular flows; determining a first measure of the total of the accumulated path characterisation metrics associated with data units of said selected subset of flows; determining a second measure indicative of the proportion of said total measure contributed by said persistently irregular flows; and determining a correction factor in dependence on the first and second measures.

Claims

1. A method of determining a correction factor for use in monitoring network traffic traversing a network, said network traffic comprising a plurality of flows of data units, each of said flows having associated therewith a flow identifier from a set of flow identifiers, said data units having associated therewith a path characterisation metric;

said method

comprising the steps of;

selecting a subset of flow identifiers from said set of flow identifiers;

determining, in respect of flows having associated therewith flow identifiers from said selected subset of flow identifiers, which flows if any are of a first type and which flows if any are of a second type in dependence on an accumulated measure of the path characterisation metrics associated with data units of said flows, flows being determined to be of a first type in the event that their respective accumulated measure is within a first range, and flows being determined to be of a second type in the event that their respective accumulated measure is within a second range;

determining a first measure of the total of the accumulated path characterisation metrics associated with data units of said selected subset of flows; and

determining a second measure indicative of the proportion of said first measure contributed by flows of said second type;

and determining a correction factor in dependence on the first and second measures.

2. A method according to claim 1, wherein said path characterisation metric is a metric indicative of a characteristic of a downstream path.

3. A method according to claim 1, wherein said path characterisation metric is a metric indicative of a characteristic of an upstream path.

4. A method according to claim 1, wherein said path characterisation metric is a metric indicative of a characteristic of an end-to-end path.

5. A method according to claim 1, wherein said path characterisation metric is a metric indicative of congestion.

6. A method according to claim 1, wherein said path characterisation metric is a metric indicative of one or more of delay, number of hops, and capability of network elements.

7. A method according to claim 1, wherein said step of determining said second measure comprises determining said measure directly.

8. A method according to claim 1, wherein said step of determining said second measure comprises determining the proportion of said first measure contributed by flows of said first type, whereby to enable the proportion of said first measure contributed by flows of said second type to be derived therefrom.

9. A method according to claim 1, wherein said data units comprise data packets, frames or messages.

10. A method according to claim 1, wherein a flow is determined to be of a first type in the event that the respective accumulated measure is within a first range indicative that data units of said flow have associated therewith a path characterisation metric indicative of dishonest, malicious, accidental or uncontrolled behaviour, and a flow is determined to be of a second type in the event that the respective accumulated measure is within a second range outside said first range.

11. A method of controlling a capability of a network using a correction factor determined in accordance with claim 1, comprising controlling said capability in dependence on said correction factor.

12. A method according to claim 11, wherein said capability is selected from policing congestion control, routing, and providing differentiated quality of service.

14. Apparatus for controlling a capability of a network using a correction factor determined in accordance with claim 1, the apparatus comprising means for controlling said capability in dependence on said correction factor.

15. Apparatus according to claim 14, wherein said capability is selected from policing congestion control, routing, and the provision of differentiated quality of service.

13. Apparatus for determining a correction factor for use in monitoring network traffic traversing a network, said network traffic comprising a plurality of flows of data units, each of said flows having associated therewith a flow identifier from a set of flow identifiers, said data units having associated therewith a path characterisation metric;

said apparatus comprising;

means for selecting a subset of flow identifiers from said set of flow identifiers;

means for determining, in respect of flows having associated therewith flow identifiers from said selected subset of flow identifiers, which flows if any are of a first type and which flows if any are of a second type in dependence on an accumulated measure of the path characterisation metrics associated with data units of said flows, such that flows are determined to be of a first type in the event that their respective accumulated measure is within a first range, and flows are determined to be of a second type in the event that their respective accumulated measure is within a second range;

means for determining a first measure of the total of the accumulated path characterisation metrics associated with data units of said selected subset of flows; and

means for determining a second measure indicative of the proportion of said first measure contributed by flows of said second type; and

means for determining a correction factor in dependence on the first and second measures.