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Network
Traffic
Management
LtCdr Samit Mehra (05IT 6018)
Guided By Dr. SK Ghosh
31/08/05
Network Traffic Management
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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
Feedback
FINAL RESULT
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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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Organizational Requirements
for managing Network Traffic?
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.
5.
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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.
2.
Usually deployed at the WAN edge of an
enterprise site.
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 Measurement
1. 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 providers
2. Ping and Traceroute
a) Path connectivity
b) Round-trip delay
3. User-application performance as seen from hosts
a) Loss
b) 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 Analysis
LAN 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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Traffic Analysis Contd..
3.Bursty Traffic: Study of P2P system related traffic, like
Gnutella have shown to be bursty in nature.
Query Responses per Second
(Rochester)
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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/ccr9501-leland.pdf
5. http://www.csd.uch.gr/
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Thank You.
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