Transcript Document
Network Traffic Management LtCdr Samit Mehra (05IT 6018) Guided By Dr. SK Ghosh 31/08/05 Network Traffic Management 1 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 31/08/05 Network Traffic Management 2 Ever since the internet has become popular, both the transmission speed and the response time remain a crucial problem…. 31/08/05 Network Traffic Management 3 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 31/08/05 Network Traffic Management 4 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 31/08/05 Network Traffic Management 5 General Process of Traffic Management TRAFFIC MEASUREMENT TRAFFIC ANALYSIS MANAGEMENT TECHNIQUES RESULT EVALUATION Feedback FINAL RESULT 31/08/05 Network Traffic Management 6 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. 31/08/05 Network Traffic Management 7 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. 31/08/05 Network Traffic Management 8 Performance Metrics Basic performance metrics : 1.Packet loss 2.Delay 3.Throughput 4.Availability 31/08/05 Network Traffic Management 9 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 31/08/05 Network Traffic Management 10 31/08/05 Network Traffic Management 11 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. 31/08/05 Network Traffic Management 12 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. 31/08/05 Network Traffic Management 13 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 31/08/05 Network Traffic Management 14 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). 31/08/05 Network Traffic Management 15 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. 31/08/05 Network Traffic Management 16 Measurement Tools 31/08/05 Network Traffic Management 17 Traffic Analysis 31/08/05 Network Traffic Management 18 Traffic Analysis 31/08/05 Network Traffic Management 19 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 31/08/05 Network Traffic Management 20 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. 31/08/05 Network Traffic Management 21 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) 31/08/05 Network Traffic Management 22 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. 31/08/05 Network Traffic Management 23 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. 31/08/05 Network Traffic Management 24 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/ 31/08/05 Network Traffic Management 25 Thank You. 31/08/05 Network Traffic Management 26