1. Chapter 6 Network Performance Measurement

2. Introduction Classification of Measurement. Tools and Techniques.

3. Introduction. Parameters which measured are: High Bandwidth.
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

4. Classification of Measurement
LAN , Backbone , End-to-End, Application
Network Measurements.
Backbone
MRTG
End-To-End (Machine to Machine)
Tcpdump
Ping / Traceroute

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

6. Tools.. (MRTG) Internal Design.. Portability…
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.

7. 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.

8. 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

9. 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.

10. 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

11. 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.

12. Java program ….4 Utility: Windump. Library: Winpcap
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.

13. Java program….8 Limitations… Improvements…. Passive Monitoring.
Non Client-Server Architecture.
Improvements….
User Given parameters – More Flexible.
Client-Server based – “network-as-a-whole”
TCPDUMP – platform independent.
GUI