Network Performance Measurement

1
Network Performance Measurement

• Introduction
• Classification of Measurement.
• Tools and Techniques.
• Examples.
• Conclusion.

2
Introduction.

• Parameters which measured are
• Bandwidth Data transferred / time
• Delay - Time taken for data to transfer (App
  level)
• Packet Loss Affects Throughput and Apps.
• High Bandwidth.
• Small Delay
• Low Packet loss

3
Classification of Measurement

• LAN , Backbone , End-to-End, Application
• Network Measurements.
• Backbone
• MRTG
• End-To-End (Machine to Machine)
• Tcpdump
• Ping / Traceroute

4
Tools

• Multi Router Traffic Grapher.
• Measures
• load on network links (Edge-Routers).
• Network Traffic.
• System Load, Login Sessions, Modem availability
• Output.
• HTML,
• LIVE presentation.
• Graphical Images.

5
Tools.. (MRTG)

• Internal Design..
• Perl Reads Traffic Counters of Router.
• C Logs Traffic Data and Creates Output.
• SNMP Perl Scripts reads SNMP variables.
• Portability
• Unix (any) Windows NT.
• Default Sample Time 5 mins.

6
Techniques

• Tcpdump/Windump
• Packet Capture.
• Supported by PCAP / JPCAP APIs.
• Explained in Java Program.
• Filters..
• Protocol TCP/UDP, 802.3, ICMP etc.
• Count
• Boolean Expressions. Examples.
• Interface. eth0, hme0 etc.

7
TCPDUMP

• Examples
• tcpdump host host1
• To print all packets arriving at or departing
  from host1
• tcpdump host host1 and \( host2 or host3 \)
• To print traffic between host1 and either host2
  or host3
• tcpdump ip host host1 and not host2
• To print all IP packets between host1 and any
  host except host2
• More examples _at_ http//www.tcpdump.org/tcpdump_ma
  n.html

8
Java Program - Windump by Hung

• Application Architecture Hierarchies
• Application
• Java program which uses JPCAP methods and
  captures packets.
• Performs Analysis on the captured packets.
• Uses JDBC and stores results in mySQL database.

9
Java program 2

• Java Package JPCAP methods used.
• Provides an Interface and system for network
  packet capture.
• JPCAP uses windump utility.
• Constructor
• Jpcap(String device, int snaplen, Boolean
  promisc, int to_ms)
• device interface for capturing data
• snaplen Maximum of bytes captured per
  packet.
• promisc Allows network device to intercept
  and capture packet.
• to_ms Time out limit

10
Java program (Methods)3

• getDeviceList()
• Returns Name of Device (Interface).
• setFilter(String condition,Boolean optimize)
• Setting protocol/Expression for capturing packet.
• getPacket()
• Captures ONE packet at a time from Interface.
• loopPacket(int count, JpcapHandler handler)
• Count times capturing packet.

11
Java program .4

• Utility Windump.
• Tcpdump equivalent utility for Windows.
• Uses a low-level library winpcap for packet
  capture.
• Library Winpcap
• It is an architecture for packet capture and
  network analysis for Win32 platforms.
• It includes Kernel-Level packet filter, a
  Low-level DLL and High-level and
  system-Independent library (wpcap.dll).
• Kernel Windows Operating system.

12
Java program.5
Begin

Connect to mysql database
Select database use
check data tables.
1
create packet data table if needed
13
Java Program6
1
Get number of Packets.
Connect to database
End
Insert packet data into Database
Get packet Data
14
Java program.7

• Analysis
• TTL Values must be equal for packets with same
  S/D.
• Flow - of S/D pair of packets per unit time.
• Delay Time stamps of consecutive packets.

15
Java program.8

• Limitations
• Passive Monitoring.
• Non Client-Server Architecture.
• Improvements.
• User Given parameters More Flexible.
• Client-Server based network-as-a-whole
• TCPDUMP platform independent.
• GUI

16
Conclusion

• Network Performance can be measured at various
  levels.
• Net. Performance can be implemented in various
  ways..using various tools.