Transcript Network Performance Measurement

Network Performance Measurement
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Introduction
Classification of Measurement.
Tools and Techniques.
Examples.
Conclusion.
Introduction.
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Parameters which measured are:
Bandwidth – Data transferred / time
 Delay - Time taken for data to transfer (App level)
 Packet Loss – Affects Throughput and Apps.
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High Bandwidth.
Small Delay
Low Packet loss
Classification of Measurement
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LAN , Backbone , End-to-End, Application
Network Measurements.
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Backbone
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MRTG
End-To-End (Machine to Machine)
Tcpdump
 Ping / Traceroute
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Tools
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Multi Router Traffic Grapher.
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Measures…
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System Load, Login Sessions,
Modem availability
Output….
 HTML,
 LIVE presentation.
 Graphical Images.
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load on network links (EdgeRouters).
Network Traffic.
Tools.. (MRTG)
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Internal Design..
Perl – Reads Traffic Counters of Router.
 C – Logs Traffic Data and Creates Output.
 SNMP – Perl Scripts reads SNMP variables.
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Portability…
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Unix (any) & Windows NT.
Default Sample Time : 5 mins.
Techniques
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Tcpdump/Windump
Packet Capture.
 Supported by PCAP / JPCAP APIs.
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Explained in Java Program.
Filters…..
Protocol – TCP/UDP, 802.3, ICMP etc.
 Count
 Boolean Expressions. – Examples.
 Interface. – eth0, hme0 etc.
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TCPDUMP…
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Examples:
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tcpdump host host1
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tcpdump host host1 and \( host2 or host3 \)
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To print traffic between host1 and either host2 or
host3:
tcpdump ip host host1 and not host2
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To print all packets arriving at or departing from
host1:
To print all IP packets between host1 and any host
except host2:
More examples @:
http://www.tcpdump.org/tcpdump_man.html
Java Program - Windump
by Hung
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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.
Java program …2
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Java Package: JPCAP methods used.
Provides an Interface and system for network packet
capture.
 JPCAP uses windump utility.
 Constructor:
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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
Java program –(Methods)…3
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getDeviceList()
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setFilter(String condition,Boolean optimize)
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Setting protocol/Expression for capturing packet.
getPacket()
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Returns Name of Device (Interface).
Captures ONE packet at a time from Interface.
loopPacket(int count, JpcapHandler handler)
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Count times capturing packet.
Java program ….4
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Utility: Windump.
Tcpdump equivalent utility for Windows.
 Uses a low-level library “winpcap” for packet capture.
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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).
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Kernel: Windows Operating system.
Java program….5
Begin
Connect to mysql database
Select database use
check data tables.
create packet data table if needed
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Java Program…6
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Get “number” of
Packets.
Connect to database
Get packet Data
Insert packet data into Database
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Java program….7
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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.
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Java program….8
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Limitations…
Passive Monitoring.
 Non Client-Server Architecture.
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Improvements….
User Given parameters – More Flexible.
 Client-Server based – “network-as-a-whole”
 TCPDUMP – platform independent.
 GUI
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Conclusion…
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Network Performance can be measured at
various levels.
Net. Performance can be implemented in
various ways..using various tools.