GB2355160A

GB2355160A - Management system and method for monitoring and presenting stress levels in a network

Info

Publication number: GB2355160A
Application number: GB9917991A
Authority: GB
Inventors: David James Stevenson; Andrew Hunter Gray; Robert James Duncan; Alastair Hugh Chisholm; Vanessa Serra; Colin Tinto
Original assignee: 3Com Corp
Current assignee: 3Com Corp
Priority date: 1999-05-10
Filing date: 1999-07-30
Publication date: 2001-04-11
Anticipated expiration: 2019-07-30
Also published as: GB9910837D0; GB2355160B; GB9917991D0

Abstract

A stress value indicative of a monitored network parameter such as network speed, traffic volume, error rates in a network device, link or part is obtained by a network management system. The stress value is presented on a display as a graphical chart comprising a linear array of segments with highlighted segments representing the quantity of stress. The stress value may be raw data or normalised to a bounded range. The segments may be of various shapes and size and coloured differently according to the stress level zones. The array may be displayed continuously or intermittently and monitors the network in a live manner. Unacceptable levels of stress may be represented as high or low on the linear array.

Description

2355160 MANAGEMENT SYSTEM AND METHOD FOR MONITORING AND PRESENTING STRESS

LEVELS IN A NETWORK The present invention relates to the management of a communications system or network, and more particularly to the monitoring of "stress" in a network. The present invention especially concerns the presentation by display, printing or otherwise of a monitored stress level in a network.

The following description is concerned with a data communications system such as a local area network (LAN), that is an Ethernet network. However, the skilled person will appreciate that the present invention will have more general applicability to other types of managed networks including wireless networks.

A local area network (LAN) typically comprises a plurality of computers, computer systems, workstations and other electronic devices connected together by a common media such as twisted pair or coaxial cable or fibre optic cable. Data can be communicated between devices on the network by means of data packets (or frames) in accordance with a predefined protocol.

Computers and other devices connected to a network can be managed or unmanaged devices. A managed device has processing capability which enables it inter alia to monitor data traffic sent from, received at, and passing through the ports of the device. Monitored data associated with the ports of the network device is stored in memory on the network device. Unmanaged devices do not have this processing capability.

It is becoming increasingly common and necessary for an individual to be appointed to manage a network. The appointed network manager (or administrator) utifises a network management station which includes network management hardware and software. In particular, the network management station is able to access management data from managed network devices using an appropriate management protocol (e.g. the SNNT protocol) and display this data for use by the network manager.

Known network management systems simply read the management data from the managed network devices and present this data to the network manager, typically in the form of numeric text, substantially unchanged. The network manager is expected to interpret the data in managing the network.

One of the important tasks of a network manager is to assess the operational perfon-nance of the various network devices and links as well as the network as a whole.

The network manager needs to know when problems are arising within the network and which particular network devices are responsible for such problems etc.

Typical problems which may affect the performance of a network include:

1. slow operating speed of the network, and individual network devices, leading to slow movement of data traffic across the network, indicated by e.g. slow response time for a given network device; 2. high volumes of data traffic on the network due to e.g. over- utilisation of the network links, network devices and the network as a whole; and 3. high error rates in the transmission of data packets across the network, indicated by e.g. the loss of data packets in a network device and errors in received data packets.

The aforementioned problems which occur in the operation of a network contribute to the poor "health" of a network. The concept of the health of a network is well known in the field of network management. In the present description, however, it is more convenient to refer to the "stress" of a network (or network device or link) rather than its "health". It will be understood that a high level of stress equates to a low level of health and vice versa. Although the present invention is described as monitoring stress in a network, it will be appreciated that the present invention is equally applicable to monitoring health in a network.

Problems which affect the performance of a network, and therefore contribute to the level of " stress", may be of greater of lesser significance. For instance, a problem with the operating speed of an end station may be less significant than a problem with the operating speed of a central core device such as a switch. Thus, the level of stress of a network depends upon a number offactors including device type, network media type and the type of problem occurring. The network manager must take all such factors into account when interpreting the management data received from the managed network devices to establish whether the performance of the network is satisfactory.

It would be desirable for a network management system to monitor characteristics of network devices and links which are indicative of problems occurring in a network which contribute to " stress", (such characteristics are referred to herein as " stress metrics" or simply "metrics") and provide data to the network manager indicative of the level of stress which is easy to interpret. Furthermore, it would be desirable to determine a stress value indicating the overall performance of each network object (a "network object" is defined herein as a network device or link) on a network and/or the overall performance of parts of or all of the network so that the network manager would not be required to interpret the monitored data, but could immediately ascertain the performance of the network (or part thereof) from the value presented by the network management system.

Furthermore, it would be desirable to provide the data, indicating the level of stress in a network of part thereof for presentation in graphical form.

In accordance with a first aspect, the present invention provides a method for presenting the level of stress of a network, network object, or part thereof, in the form of a predefined graphical chart comprising a linear array of segments, each segment representing a defined quantity of stress in said network, network object, or part thereof, the method comprising:

obtaining a stress value for the network, network object, or part thereof, determining the number of segments in the graphical chart corresponding to the stress value, and providing image data to apparatus for presenting said graphical chart with the -4 determined number of segments highlighted.

In accordance with a second aspect, the present invention provides a computer readable medium having a computer program for carrying out the method of the first aspect of the present invention.

In accordance with a third aspect, the present invention provides network management apparatus for presenting the level of stress of a network, network object, or part thereof, in the form of a predefined graphical chart comprising a linear array of segments, each segment representing a defined quantity of stress in said network, network object, or part thereof, the apparatus comprising:

a processor for obtaining a stress value for the network, network object, or part thereof and determining the number of segments in the graphical chart corresponding to the obtained stress value, said processor providing image data to apparatus for presenting said graphical chart with the determined number of segments highlighted.

Accordingly, the network management system and method ofthe present invention provides a convenient way of presenting a stress value which provides a useful indication of the performance of a network, the network devices and links forming the network, or parts thereof, in a way which is easy for a network manager to interpret.

The stress value may be presented using any apparatus capable of producing graphical images, such as a visual display unit or printer. The display unit or printer may receive the image data via another application capable ofimporting and utilising graphical data. When presented on a display, advantageously the stress value may be displayed in a dynamic manner so that the displayed indication represents a "live" state of the performance of the network.

An embodiment of the present invention will now be described, by way of example, with the reference to the accompanying drawings, in which:

Figure I is a block diagram of a typical network having a network management station incorporating a preferred embodiment of the present invention; Figure 2a is a schematic view of the preferred manner of presentation of data in graphical form in accordance with the present invention; and Figure 2b is an example of the manner of data presentation of Figure 2a; Figure 3 shows the display of a network management station of the network of Figure I displaying data in graphical form in accordance with the example of Figure 2; and Figure 4 is a flow chart showing the steps carried out by a computer program for obtaining image data for presentation in a graphical form in accordance with a preferred embodiment of the present invention.

Figure I shows a typical network incorporating a network management system according to the present invention. The network includes a network management station 3A which incorporates the necessary application hardware and software for network management. In particular, the network management station includes a processor such as a CPU, a memory and a disk drive, and preferably also a MODEM for internet access, as well as user interfaces such as a keyboard and mouse, a visual display unit and a printer.

Network management application software in accordance with the present invention is loaded into the memory of management station 3A for processing data as described in detail below with reference to Figure 3. The network management station 3A is connected by the network media (e.g. Ethernet cable) 5 to a plurality of managed nQtwork devices including core devices such as network switch 7 and hubs I I and to end stations including personal computers 3 and workstations. The network may also include unmanaged devices, for example peripheral devices such as shared printers.

The network management station is capable of communicating with the managed network devices such as network switch 7 and hubs I I by means of a network management protocol (e.g. the SNMP protocol) in order to obtain network management data. In particular, the network management station 3A can periodically retrieve management data from each managed network device. The retrieved data relates to characteristics of the managed device which are indicative of stress, that is each type of data is a "stress metric" or simply a "metric" as previously defined. The network management station 3A may present the retrieved raw data for the stress metric in graphical form in accordance with the present invention.

However in apreferred embodiment, the network management station 3Aincludes a processor which processes the raw data for each metric for each type of network device and link to determine the appropriate perceived stress level. The thus determined stress level is preferably a normalised stress value, i.e. a stress value within a predefined range, for example 0 - 100. The processor ofthe network management station preferably further aggregates the normalised stress values for each device and link to provide a stress value for the device or fink as a whole, and similarly aggregates stress values for some or all of the devices and links to obtain an overall stress value for the whole or part ofthe network.

The manner in which the data is retrieved and processed by the network management station 3 A in accordance with the preferred embodiment is as described in our copending UK patent application (which claims priority from UK Patent Application No 9910838.3) entitled "Management System and Method for Monitoring Stress in A Network" filed simultaneously herewith and hereby incorporated by reference.

The network management station thus provides a normalised stress value for a particular measured metric for a particular network object. For example, the stress value may be normalised to a value within the range 0 - 100. In accordance with the present invention, the stress value is then mapped onto a predefined graphical chart or "stress bar" as illustrated in Figure 2. As shown in Figure 2a, the preferred form of stress bar includes three portions, a main portion 20, a secondary portion 24 and a third portion 26. The main portion 20 is formed by a linear array ofgenerally rectangular segments 22 extending horizontally. The total number of segments 22 in the main portion 20 of the stress bar typically represents at least the maximum stress value i.e. 100. A normalised stress value determined by the management station is mapped onto the stress bar by highlighting the corresponding number of successive segments from left to right. Thus, for example, ifthe main portion 20 ofthe stress bar includes 50 substantially equal segments for representing stress values between 0 and 100, each segment represents a stress quantity of 2, so that a normalised stress value of 50 will be represented by highlighting the first 25 successive segments from the left of the stress bar.

In one embodiment, the graphical chart is presented on the display screen of the network management station and the highlighting is achieved by illumination of segments 22. The network manager, using this embodiment, may initiate the display of the stress bar at periodic intervals to obtain "snap shot" views of the level of stress. Alternatively, the network manager may operate the embodiment for the continuous display ofthe stress bar. In this case, the stress value will be obtained automatically at regular time intervals and used to modify the stress bar, if necessary. For short time intervals, the segments 22 will be dynamically illuminated on the network management station display screen in response to changes in the periodically determined normalised stress value, to represent a "five" stress level.

In accordance with the present invention, the processor of the network management station 3A runs the computer program of the software application as shown in Figure 3. In step 10 1 the processor provides or otherwise obtains the stress value to be mapped onto the graphical chart and in step 102 using the stress value deternfines the number of segments in the graphical chart which represent the stress value. The processor then provides image data to the display or printer of the network management station or any other presentation apparatus in step 104, for presenting the graphical chart representing the stress value, as described above.

As shown in Figure 2, and in accordance with the preferred embodiment of the present invention, a secondary portion 24 of the stress bar is additionally provided, lying parallel to, and in alignment with, the main portion 20 of the stress bar. The stress bar and in particular the secondary portion is divided into three stress zones 24a-c. Each zone represents a range of stress values and in step 103 of the computer program illustrated in Figure 3, the program determines the zone into which the stress value falls and includes this in the image data provided in step 104.

The first zone 24a represents acceptable network performance. When the stress value is at a level within this zone (which has a predefined range for a given metric), only a small number of segments in the stress bar are highlighted, and the word "low" is presented in first zone 24a of the secondary portion of the stress bar. This is illustrated in Figure 2b and the stress bar labelled "Device One" in the enlarged view of Figure 3.

A stress value in the predefined range of the middle zone 24b represents performance which is marginal. When the number of segments highlighted in the main portion 20 of the stress bar falls within the predetermined range for the second zone 24b of the stress bar, the word "warning" is presented in the second zone 24b. This is illustrated by the stress bar labelled "Device Two" in the enlarged view of Figure 3. Finally, when the (non-nalised) stress value is maximum, it falls within the third zone 24c. This represents an unacceptable stress level. In this case, in one embodiment all of the segments in the main portion 20 of the stress bar 20 are highlighted and the word "high" is presented in the third zone 24c of secondary portion 24 of the stress bar- Alternatively, in another embodiment, the network management station further manipulates the raw data used to obtain the normalised stress value, to provide data which is indicative of the extent to which the stress level is above the unacceptable value (for example, by recalculating the stress value to be normalised with an increased range, say 0 to 125). This data is then mapped onto the stress bar so as to highlight a proportion of the segments in the high zone as shown by the stress bar labelled "Device Three" in the enlarged view of Figure 3.

As will be apparent from the above, and with reference to Figures 2 and 3, the stress level of the network or part thereof is indicated by the number of highlighted segments on the main portion 20 of the stress bar. The segments 22 may be presented in different colours as the stress increases and moves through the three zones. For instance, the segments corresponding to the first zone 24a may be presented in green, the segments corresponding to the second zone 24b may be presented in amber, and the segments corresponding to the third zone 24c may be presented in red. Alternatively, all the segments may be presented in the relevant colour, i.e. red, amber or green, depending upon the zone into which the stress value falls. This colour change may additionally or alternatively be represented in the colour illumination of the words "low", "warning" and "high" in the colours, green, amber and red respectively, in the appropriate zone of the secondary portion 24 of the stress bar. Further indications of the acceptability of the stress level, may be achieved using a third portion 26 of the stress bar between the main portion 20 and the secondary portion 24, as explained fimther below, to give the user both a positional and a colour cue that a problem has arisen.

Typically, the boundary between the warning and high zones in the secondary portion 24 represents a maximum normalised stress value, for example 100. This boundary is preferably always defined at a fixed point on the predefined stress bar for all metrics. Normalised stress levels for a plurality of metrics can be represented by a plurality of stress bars for different metrics as illustrated, for example, in a vertical stack on the display (i.e. with the stress bars in alignment) as shown in Figure 3. Suchavertical stack could equally be presented on paper or any other printed medium using a printer.

Because the stress levels for all metrics are normalised within the same range, it is possible to use substantially identical stress bars for mapping the stress level of each metric.

However, the boundary between the low and warning zones in the secondary portion 24 of the stress bar may be different for different metrics. This stress boundary is typically predefined within the network management system for each metric but may be adjusted by the user. In order to provide the network manager with an indication of the boundaries between the low, warning and high zones in portion 24, the third portion 26 of the stress bar may be used. For instance, the portion 26 may be highlighted using the three colours green, amber and red above the low, warning and high zones respectively, so that it is clear to the user where the boundaries he, and thus how close the stress level, represented by the highlighted segments 22, is to the relevant boundary. Since the boundaries are fixed, there will be no colour change in the portion 26 with time, and in the case of a "live" display of the stress bar, the portion 26 would be constantly illuminated. By providing the stress values in graphical form as a stack of parallel, horizontally extending bars, with each stress bar having the same stress boundary for maximum stress, the user can easily compare the different stress values side by side and determine which stress value, and therefore network object, requires the most urgent attention.

As the skilled person will appreciate, the described "Stress bar" provides the user with a useful graphical representation of the level of stress within a network. The network management system is able to automatically monitor the metrics at regular intervals to obtain "live" data for the network, and process this data for representation as a stress bar so that the user is able to monitor the performance of a network in a live manner.

Various modifications may be made the described embodiment. For instance, although the stress bar has been described with increasing stress represented from left to right, it would be possible for this to be from right to left. Furthermore, although the graphical chart has been illustrated and described as a bar extending horizontally on the display screen, it would equally be possible for the stress bars to extend vertically with the segments illuminated from bottom to top or top to bottom. The segments need not be rectangular, but could be any shape, including circular or square, provided that they can be arranged as a linear array. Furthermore, the size and shape of the segments need not be uniform but could vary along the length of the array, for instance by increasing in size to represent high levels of stress. It is intended to include all such variations and modifications which fall within the scope of the present invention as defined in the accompanying claims.

Claims

CLAIMS:

1. A method for presenting the level of stress of a network, network object, or part thereof, in the form of a predefined graphical chart comprising a linear array of segments, each segment representing a defined quantity of stress in said network, network object, or part thereof, the method comprising:

obtaining a stress value for the network, network object, or part thereof, determining the number of segments in the graphical chart corresponding to the stress value, and providing image data to apparatus for presenting said graphical chart with the determined number of segments highlighted.

2. A method as claimed in claim 1, wherein the segments of the graphical chart are highlighted by highlighting the determined number of successive segments from one end of the linear array.

3. A method as claimed in claim I or claim 2, wherein the graphical chart has a fixed number of segments representing a bounded range of stress values.

4. A method as claimed in claim 3, wherein said stress value is a raw data value, and the fixed number of segments is greater then or equal to the number of segments corresponding to a threshold stress value representing an unacceptable level of stress in said network, network object, or part thereof.

5. A method as claimed in claim 3, wherein the stress value is a data value within a predefined bounded range and the fixed number of segments is greater than or equal to the number of segments corresponding to the ma.,dmum value of the bounded range.

6. A method as claimed in any preceding claim, wherein each segment in the graphical chart represents the same quantity of stress in said network, network object, -12 or part thereof

7. A method as claimed in claim 6, wherein said segments in said graphical chart are of uniform size.

8. A method as claimed in claim 6 or claim 7, wherein said step of determining comprises dividing the stress value by the quantity of stress represented by each segment.

9. A method as claimed in any preceding claim, wherein the linear array of segments is divided into zones, each zone including a plurality of segments, wherein the segments in each zone are highlighted differently from the segments in other zones.

10. A method as claimed in claim 9, wherein the segments in each zone are highlighted in a predetermined colour.

11. A method as claimed in any preceding claim, wherein said graphical chart further includes a linear region lying parallel to said linear array of segments, said linear region having subregions, each subregion corresponding to a range of stress values, wherein when the stress value falls within the range of a subregion, the image data provided to the presentation apparatus includes said linear region with the respective subregion highlighted.

12. A method as claimed in claim 9, wherein the linear region includes three subregions, a first subregion representing low stress values and presenting the word "low" when highlighted; a second subregion representing moderate stress values and presenting the word "warning" when highlighted, and a third subregion representing unacceptably high stress values and presenting the word "high" when highlighted.

13. A method as claimed in claim I I or claim 12, wherein the linear array of segments is divided into zones, each zone including a plurality of segments corresponding to the stress values in the range of stress values for each subregion of said linear region.

14. A computer readable medium carrying a computer program for carrying out the method as claimed in any preceding claim.

15. A method as claimed in any one of claims I to 13, further including displaying said graphical chart on a display.

16. A method as claimed in claim 15, further comprising periodically updating said graphical chart on said display by periodically repeating said method, so that said graphical chart on said display represents a current level of stress ofthe network, network object, or part thereof

17. A method for presenting the level of stress of a network, network object, or part thereof, in the form of a graphical chart substantially as hereinbefore described, with reference to, and as shown in, the accompanying drawings.

18. Apparatus for presenting the level of stress of a network, network object, or part thereof, in the form of a predefined graphical chart comprising a linear array of segments, each segment representing a defined quantity of stress in said network, network object, or part thereof-, the apparatus comprising:

19. Apparatus as claimed in claim 18, wherein the segments of the graphical chart are highlighted by highlighting the determined number of successive segments from one end of the linear array.

20. Apparatus as claimed in claim 18 or claim 19, wherein the graphical chart has a fixed number of segments representing a bounded range of stress values.

21. Apparatus as claimed in claim 20, wherein said stress value is a raw data value, and the fixed number of segments is greater then or equal to the number of segments corresponding to a threshold stress value representing an unacceptable level of stress in said network, network object, or part thereof

22. Apparatus as claimed in claim 20, wherein the stress value is a data value within a predefined bounded range and the fixed number of segments is greater than or equal to the number of segments corresponding to the maximum value of the bounded range.

23. Apparatus as claimed in any one of claims 18 to 22, wherein each segment in the graphical chart represents the same quantity of stress in said network, network object, or part thereof

24. Apparatus as claimed in claim 23, wherein said segments in said graphical chart 15 are of uniform size.

25. Apparatus as claimed in claim 23 or claim 24, wherein said processor detern-dnes the number of segments by dividing the stress value by the quantity of stress represented by each segment.

26. Apparatus as claimed in any one of claims 18 to 25, wherein the linear array of segments is divided into zones, each zone including a plurality of segments, wherein the segments in each zone are highlighted differently from the segments in other zones.

27. Apparatus as claimed in claim 26, wherein the segments in each zone are highlighted in a predetermined colour.

28. Apparatus as claimed in any one of claims IS to 27, wherein said graphical chart further includes a linear region lying parallel to said linear array of segments, said linear 30 region having subregions, each subregion corresponding to a range of stress values, wherein when the stress value falls within the range of a subregion, the image data provided to the presentation apparatus includes said linear region with the respective subregion highlighted.

29. Apparatus as claimed in claim 28, wherein the linear region includes three sub regions, a first subregion representing low stress values and presenting the word "low" when highlighted; a second subregion representing moderate stress values and presenting the word "warning" when highlighted, and a third subregion representing unacceptably high stress values and presenting the word "high" when highlighted.

30. Apparatus as claimed in claim 28 or claim 29, wherein the linear array of segments is divided into zones, each zone including a plurality of segments corresponding to the stress values in the range of stress values for each subregion of said linear region.

31. Apparatus as claimed in any one of claims 18 to 30, farther including a display for receiving said image data from said processor and displaying said graphical chart.

32. Apparatus as claimed in claim 3 1, wherein said processor is adapted to periodically obtain a current stress value for the network, network object, or part thereof, determine the number of segments in the graphical chart corresponding to the current stress value, and provide image data to said display for displaying an updated graphical chart on said display.

33. Apparatus as claimed in any one of claims 18 to 32, ffirther including a printer for receiving said image data from said processor and printing said graphical chart.

34. Apparatus for displaying the level of stress of a network, network object, or part thereof, in the form of a graphical chart substantially as hereinbefore described, with reference to, and as shown in, the accompanying drawings.