Transcript TraceQoS

10th TF-NGN meeting, Rome, February 6th-7th 2003
TraceQoS
A tool for locating QoS failures on an
Internet path
Chris Welti, Network Engineer, SWITCH
2003 © SWITCH
Outline
•
•
•
•
•
Introduction
What is TraceQoS?
Demonstration
Implementation
System requirements
2003 © SWITCH
2
Introduction
- Use of Internet for transfer of real-time processed
data (e.g. video streams)
- Depend on certain QoS of underlying network (e.g.
max. dv)
- Difficult to locate end-2-end QoS performance
problems in IP networks
- Crossing management domains
- Network operators claim their networks work
flawlessly
- No common tool for measuring one-way metrics
segment by segment over an end-2-end path
2003 © SWITCH
3
What Is TraceQoS?
• Active one-way measurement system for locating
QoS „failures“ on an IP path from source to
destination
• On demand tests
• TraceQoS measures OWD, OWDV, OWPL segment
by segment over end-2-end path
• Concurrent measurements on the subpaths
• Dynamically displays results while test is in
progress
-> Helps to locate segments on the investigated path
where QoS performance is not sufficient
2003 © SWITCH
4
A Sample TraceQoS Scenario
Source
Router
1
Link 1
Link 2
Router
2
Link 3
Router
3
Link 4
Destination
TS1
tsr2
rts2
tsr1
rts1
mp2
mp1
mp3
TS2
LEGEND:
TS = TraceQoS server
rts = link from router to TS
tsr = link from TS to router
mp = measurement path
2003 © SWITCH
5
TraceQoS User Interface
• TraceQoS client
• Perl Script
• User Parameters:
–
–
–
–
–
–
Destination host
Test port
Preferred address family (IPv4/IPv6)
Number of packets to send
Packet size
Packet rate
2003 © SWITCH
6
TraceQoS Result Viewer
•Dynamic display of current test traffic while in progress
(OWD, OWDV, packet loss)
2003 © SWITCH
7
TraceQoS Result Viewer (2)
•Result visualisations of the test
session (qosplot)
•Can be displayed in a webbrowser.
2003 © SWITCH
8
TraceQoS
LIVE DEMO
2003 © SWITCH
9
Implementation
• TraceQoS servers connected to routers on the path to be
investigated
• TraceQoS client:
-
Traceroute to destination
Looks for matching TraceQoS servers along the path found
Sends test requests to the TraceQoS servers found
Polls packet traces from the TraceQoS servers involved
Generates statistics and displays them to the user
2003 © SWITCH
10
Control protocol
•
•
-
Tests are initiated through HTTP (CGI)
Perl-scripts on TraceQoS servers to:
Start a sender test session
Start a receiver test session
Get current packet-trace
Stop a test session
2003 © SWITCH
11
TraceQoS operating sequence
Web Server
(TS0)
User
1
traceQoS.cgi
(TM)
2
launchTest.cgi
(TSC)
launchReceiver.cgi
(TRC)
Web Server
TS1
Web Server
TS2
traceQoS.cgi
(TM)
traceQoS.cgi
(TM)
launchTest.cgi
(TSC)
launchTest.cgi
(TSC)
3
getResults.cgi
(TDA)
launchReceiver.cgi
(TRC)
launchReceiver.cgi
(TRC)
getResults.cgi
(TDA)
getResults.cgi
(TDA)
6
8
4
TestSender.C
(TTC)
9
TestSender.C
(TTC)
7
TestReceiver.C
(TTS)
TestReceiver.C
(TTS)
Disk
Disk
5
TestReceiver.C
(TTS)
TestSender.C
(TTC)
Disk
2003 © SWITCH
12
TraceQoS Test Traffic
•
•
•
•
C programs to generate and receive test traffic
Fixed size UDP packets
IPV4 or IPV6
Sent in poisson-distributed time intervals to avoid
synchronization effects
• Packets contain:
-
Test ID
Sequence number
Timestamp of sending
Padding data
2003 © SWITCH
13
Interesting Test Results
NTP time drift
2003 © SWITCH
14
Interesting Test Results (2)
Busy router CPU
2003 © SWITCH
15
System Requirements For The Prototype
• TraceQoS server:
- Well-connected Linux machine
(lightly loaded, short & fast connection to router)
- Clock synchronization (GPS or NTP) for OWD
measurements
- Must be able to accept & send packets at least on
UDP port 34671 (test traffic) and TCP port 80 (HTTP,
control protocol)
- Software: Web Server with CGI (preferrebly Apache
1.3)
- Perl 5 and some Perl-libraries (libwww, file-tail, etc.)
2003 © SWITCH
16
THE END
Thank you for your attention!
For more information about
TraceQoS contact me: [email protected]
2003 © SWITCH
17