Apparatus for quality of service evaluation and traffic measurement

• US 6,563,796 B1
• Filed: 03/15/1999
• Issued: 05/13/2003
• Est. Priority Date: 03/18/1998
• Status: Expired due to Fees

• Current Assignee: Nippon Telegraph and Telephone Corporation
• Original Assignee: Nippon Telegraph and Telephone Corporation
• Inventors: Saito, Hiroshi
• Primary Examiner(s): TON, DANG T
• Application Number:
  US09/267,768
• Time in Patent Office: 1,520 Days
• Field of Search: 370/389, 370/399, 370/229, 370/230, 370/231, 370/428, 370/411, 370/412, 370/395.21, 370/695.3, 370/395.4, 370/395.41, 370/395.42, 370/395.61, 370/351, 370/352, 370/400, 370/401, 370/503, 370/507, 370/508, 370/509, 370/516, 370/517, 370/518, 370/519, 370/252, 370/169, 370/465, 370/469, 709/232
• US Class Current: 370/252
• CPC Class Codes: H04L 12/5601 Transfer mode dependent, e.g. ATM
• CPC Class Codes: H04L 2012/5625 Operations, administration and maintenance [OAM]
• CPC Class Codes: H04L 2012/5628 Testing
• CPC Class Codes: H04L 2012/5636 Monitoring or policing, e.g. compliance with allocated rate, corrective actions
• CPC Class Codes: H04L 2012/5638 Services, e.g. multimedia, GOS, QOS
• CPC Class Codes: H04L 2012/5649 Cell delay or jitter
• CPC Class Codes: H04L 2012/5651 Priority, marking, classes
• CPC Class Codes: H04L 2012/5681 Buffer or queue management
• CPC Class Codes: H04L 41/145 involving simulating, designing, planning or modelling of a network
• CPC Class Codes: H04L 43/00 Arrangements for monitoring or testing data switching networks
• CPC Class Codes: H04L 43/106 using time related information in packets, e.g. by adding timestamps
• CPC Class Codes: H04L 43/55 Testing of service level quality, e.g. simulating service usage
• CPC Class Codes: H04L 49/205 Quality of Service based
• CPC Class Codes: H04L 49/30 Peripheral units, e.g. input or output ports
• CPC Class Codes: H04L 49/3009 Header conversion, routing tables or routing tags
• CPC Class Codes: H04L 49/55 Prevention, detection or correction of errors
• CPC Class Codes: H04Q 11/0478 Provisions for broadband connections

Abstract

The present invention concerns an apparatus for evaluating the quality of service in a network. The QoS evaluation apparatus includes an arrival detection section to provide a timestamp to a specific processing unit included in a packet that arrives at an attention point in the network and is branched off by duplicating from a switching system. An estimation section estimates the arrival times of the plurality of processing units arriving at the attention point, and a simulation section simulates arrival times corresponding to the estimated arrival times at the attention point, produced by the arrival time estimation section, according to a pre-determined logic equation.

Claims

1. A quality of service evaluation apparatus comprising:

an arrival detection section for accepting a packet duplicated and branched from packets passing through an attention point in a switching system, and assigning a timestamp of arrival time to a specific processing unit included in said packet;

an estimating section for estimating arrival times of said processing units included in said packet at said attention point on a basis of said timestamp for said specific processing unit given by said arrival detection section; and

a simulation section for simulating arrival time of said packet at said attention point actions of said attention point according to a simulation logic in which arrival time to correspond to said estimated arrival time at said attention point obtained by said estimating section was pre-set.

2. An apparatus according to claim 1, wherein said switching system is an ATM switching system, and said attention point is an output-line buffer in said ATM switching system.

3. An apparatus according to claim 1, wherein said processing unit is a cell and said specific processing unit is a first cell in an object packet.

4. An apparatus according to claim 2, wherein said processing unit is a cell, and said specific processing unit is an individual cell in an object packet.

5. An apparatus according to claim 3, wherein said estimating section includes a processing section for estimating an arrival time of an (i)th. cell in said packet according to a relation:

[a timestamp of said first cell+(i−

1)×

(cell length/input-line speed)].

6. An apparatus according to claim 3, wherein said estimating section includes a processing section which calculates an estimated arrival time of an (i)th. cell including in said packet from a relation:

[an estimated arrival time of the first;

cell+(i−

1)×

(cell length/input-line speed)],

where said estimated arrival time of the first cell is given by a sum of a base time and an estimated value of a time interval required for cells output between a reference time and a timestamp of the first cell to arrive at said attention point;

wherein

when cells are output from a switching system without creating an idle interval between the first cell of a preceding packet and the first cell of said object packet, then said base time is equal to an estimated arrival time of the first cell of the preceding packet, and said reference time is equal to a timestamp of the first cell of the preceding packet; and

when there is an idle interval between the first cell of a preceding packet and the first cell of said object packet, then said base time is equal to a reference time so as to indicate a time when a most recent idle interval becomes non-idle.

7. An apparatus according to claim 3, wherein said estimating section is provided with a table that records estimated cell arrival rates at each instant of time, and is provided with a computing section to read out an estimated value “

a”

corresponding to a time indicated by a timestamp of a packet, and

if “

a”

≧

1, an estimated arrival time t(1) for the first cell of an object packet is calculated from a relation;

[an estimated arrival time t′

(1) of the first cell of a preceding packet]+[(the object packet timestamp t)−

(the preceding packet timestamp t′

)]/(estimated cell arrival rate “

a”

); and

if “

a”

<

1, an estimated arrival time t(1) for the first cell of an object packet is calculated from a relation;

(an arrival time of the of the first cell of the object packet)+(a waiting time of the first cell of the object packet)=(transmitting time of the first cell of the object packet)=(a timestamp t of the object packet).

8. An apparatus according to claim 1, wherein said switch system is a router and said attention point is a network interface section connected to output-line in the router.

9. An apparatus according to claim 8, wherein said processing unit is a packet, and said estimating section includes a processing section to calculate an estimated arrival time for an (i+1)th. packet so that:

when an (i)th. completion time of packet transmission is followed continually with an (i+1)th. starting time of packet transmission, a relation is used such that;

[(i)th. packet estimated arrival time+(i+1)th. starting time of packet transmission]/2, where said (i+1)th. starting time of packet transmission is obtained by subtracting a value of (packet length of (i+1)th. packet)/(output-line speed) from the timestamp of (i+1)th. packet; and

when an (i)th. completion time of packet transmission is not followed continually with an (i+1)th. starting time of packet transmission, a relation is used such that;

(i+1)th. packet estimated arrival time=an (i+1)th. starting time of packet transmission, where said (i+1)th. starting time of packet transmission is obtained by subtracting a value of (packet length of (i+1)th. packet)/(output-line speed) from the timestamp of (i+1)th. packet.

10. A traffic measuring apparatus comprising:

a low layer processing section for performing protocol processing of lower level functional layers residing adjacently below an attention protocol layer in a network for transferring information using a specific processing unit;

an object condition discrimination section for deciding whether or not measurement conditions specified by an API, are satisfied in a data unit that has been subjected to processing in said low layer processing section; and

an measuring operation section for carrying out measuring actions specified by said API for a data unit that has been judged to satisfy said measurement conditions; and

an application section for computing desired contents of traffic measurement by manipulating raw data output from said measuring operation section.

11. A traffic measuring apparatus according to claim 10, wherein said traffic measuring apparatus further includes an API conversion section for converting upper level APIs that determine user-friendly parameters to a general purpose API for purposes of taking traffic measurements, wherein said parameters may include conditions for an object to be measured, measurement items and measurement methods, represented by terms such as addresses or protocol types in each protocol layer, protocol data units in each protocol layer;

and said object condition discrimination section and said measuring operation section use said general purpose API in place of said API.

12. A traffic measuring apparatus according to claim 10, wherein an API used by said measuring operation section is a logic equation based on bit values and time information contained in data units.

13. A traffic measuring apparatus according to claim 11, wherein an API used by said measuring operation section is a logic equation based on bit values and time information contained in data units.

14. A traffic measuring apparatus according to claim 10, wherein said API is an upper level API for determining user-friendly measurement parameters including conditions for an object to be measured, measurement items and measurement methods, represented by terms such as addresses or protocol types in each protocol layer, protocol data units in each protocol layer.

15. A computer program product containing a computer program recorded on a computer usable medium for causing a computer to evaluate a quality of service based on a packet that propagate through an attention point of an switching system, said computer program effecting the steps of:

assigning a timestamp of arrival time to a specific processing unit included in inputted said packet;

estimating arrival times of said processing units included in the packet using said timestamp assigned to said specific processing unit; and

simulating an arrival time said processing units at said attention point and actions of said attention point according to a simulation logic in which time corresponding to said estimated arrival time at said attention point was pre-set.

16. A computer program product containing a computer program recorded on a computer usable medium for causing a computer to carry out traffic measurements in a network using data units that have been processed for lower level functional layers residing immediately below an attention protocol layer for transmitting information using a specific processing unit, said computer program effecting the steps of:

deciding whether or not one of said data units satisfies object conditions specified by an API;

carrying out measurement actions on those data units that have been judged to satisfy object conditions, according to conditions specified by said API; and

calculating desired contents of traffic measurement by manipulating raw data produced by measurement actions.