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NetworkTraffic

ManagementLtCdr Samit Mehra (05IT 6018)

Guided By Dr. SK Ghosh

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What is a Computer Network?

A computer network is a data communications system which

interconnects computer systems at various different sites. A network may be composed of any combination of

LANs, or WANs.

Ref: http://largebande.gc.ca/pub/technologies/bbdictionary.html

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Ever since the internet has become popular, both the

transmission speed and the response time remain a

crucial problem….

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What is Network Traffic?

1. Density of data present in the network.

2. Communication devices access resources and also get requests to carry out some work.

3. So a lot of request, response and control data.

4. Load on the network.

5. Other devices may get delayed in their requirements.

Electric Signal – Bit –Byte- Frame – Packet – Message- Session – Application Data

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Traffic Management

Controlling network traffic requires limiting bandwidth to certain

applications, guaranteeing minimum bandwidth to others, and marking traffic with high or low priorities. This exercise

is called traffic management.

Ref: The Traffic Management Handbook – Allot Communications

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General Process of Traffic Management

TRAFFIC MEASUREMENT

TRAFFIC ANALYSIS

MANAGEMENT TECHNIQUES

RESULT EVALUATION

FINAL RESULT

Feedback

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Organizational Requirements for managing Network Traffic?

1. To guarantee maximum bandwidth to mission critical applications.

2. To block music or video downloads.

3. To block music file sharing and avoid copyright infringement liability.

4. To delay investments in additional network capacity.

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5. Service monitoring - making sure things keep working.

6. Cost recovery - session times and traffic volumes can provide billing data.

7. Research - an improved understanding of what's happening should allow us to

8. Improve network performance.

Organizational Requirements for managing Network Traffic?

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Performance Metrics

Basic performance metrics :

1.Packet loss

2.Delay

3.Throughput

4.Availability

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Where should we manage traffic?1. Usually deployed at the WAN edge of an

enterprise site.

2. The LAN-WAN juncture is also where both Internet and Intranet traffic enters and exits the enterprise.

Traffic Management

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Approaches for Traffic Measurement1. Server Logs:

• Web servers configured to record information about all client requests.

• Eg – most servers have a log file ‘access’ where requests and responses are saved.

• Each line of the access log contains information on a single request for a document.

• An example is:

cs.fudan.edu.cn – [15/Aug/1999:14:50:05 - 0600] "GET/HTTP/1.1" 200 1200

• This data can be used to characterize web traffic.

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Approaches for Traffic Measurement

2. Passive Measurement:

•Choose an appropriate site and passively capture every IP packet through it.

• Ideal site would be one through which many connections pass.

Eg a major gateway site.

•Many monitoring platforms. One such platform is TCPDump based WinDump.

•Users can build complicated Boolean expressions to decide which data packets to catch.

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Approaches for Traffic Measurement

3. Active Measurement:

Users or providers are directly related to the activities of measurement in the following ways:1. Injection of probes into network by users and providers2. Ping and Traceroute

a) Path connectivityb) Round-trip delay

3. User-application performance as seen from hostsa) Lossb) Delay c) Throughput

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Processes for Traffic Management

Once a problem of traffic management has been identified, the following tasks should be worked through in detail:

1. Decide what is to be measured.

2. Decide where to put traffic meters.

3. Decide how data will be read from the meters and consolidated into a central database.

4. Decide what reports will be generated, and how they will be published (e.g. on demand via a web page).

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Types of Measurement Tools• Local Systems:

•NETSTAT,TCPDUMP,ETHEREAL,NTOP

Remote End Systems:

•MIBS, IF-MIB, SNMP, MRTG

Routers:

•NETFLOW(CISCO), LFAP(ENTERASYS)

Measurement Limits: Experiments have shown that these tools can currently handle up to several gigabits.

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Measurement Tools

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Traffic Analysis

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Traffic Analysis

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Traffic AnalysisLAN Traffic: Consecutive years of monitored LAN traffic has shown it to be self similar in nature.

Ref: http://www.acm.org/sigs/sigcomm/ccr/archive/1995/jan95/ccr-9501-leland.pdf

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Traffic Analysis

Traffic on the WAN has been found to follow three models.

1. Random Traffic

2. Poisson Model: Earlier traffic was also found to be distributed as per the Poisson’s equation however further research has shown this model to be a failure.

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Query Responses per Second (Rochester)

3.Bursty Traffic: Study of P2P system related traffic, like Gnutella have shown to be bursty in nature.

Traffic Analysis Contd..

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Network Traffic Management

Here it is evident how traffic management has increased the available bandwidth for Mission Critical Applications, thus ensuring that the most important functions of an organization do not have to wait.

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Conclusion

1. Traffic management is the key for quality of service.

2. Complex networks need the support of detailed measurement.

3. Measurement and Models play a crucial role

• Constructing a real time network wide view.

• Detecting, diagnosing and fixing problems.

4. Traffic Management can drastically increases the available bandwidth for mission critical applications, thus benefiting the organization tremendously.

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References.

1. http://largebande.gc.ca/pub/technologies/bbdictionary.html

2. The Traffic Management Handbook – Allot Communications

3. Measurement and analysis of IP network traffic - Cen Zhiwei Gao Chuanshan Cong Suo Han Liangxiu. Dept. of Computer Science, Fudan University, Shanghai 200433, China

4. http://www.acm.org/sigs/sigcomm/ccr/archive/1995/jan95/ccr-9501-leland.pdf

5. http://www.csd.uch.gr/

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Thank You.