Transcript Transferring packets of data through TCP and UDP

Transmitting and Tracking
Packets of Data Through
The TCP and UDP
Network Protocols
Todd Deshane
Ashwin Venkatraman
McNair Program
Clarkson University
Overview

Transmission Control Protocol (TCP)

User Datagram Protocol (UDP)

Research questions and methodology

Data analysis and conclusions
Internet Protocols
user X
English
user Y
e-mail client
SMTP
e-mail server
TCP/UDP server
TCP/UDP
TCP/UDP server
IP server
ethernet
driver/card
IP
IEEE 802.3 standard
electric signals
IP server
ethernet
driver/card
CS454 (Computer Communication)
Clarkson University, Summer 2002
Transmission Control
Protocol (TCP)

Handshaking



Connection-oriented
service!
Reliable data transfer
Flow Control
Congestion Control
User Datagram
Protocol (UDP)

No Handshaking!



Connectionlessoriented service!
No Reliable data transfer
No Flow Control
No Congestion Control
Research Questions

TCP



Elegant Protocol
Lots of nice features
Slower

UDP



Barebones Protocol
Lacks reliability
Faster
How much do we pay to use TCP?
How do we measure performance?
What causes the differences in performance?
Measuring Network Traffic

Basic terminology:



Network data represented in packets
Packet sizes represented in bytes
Things to measure:


Elapsed Time
Total data sent … Total received


Effective Throughput (data received/time)
Efficiency (Percent received)
Procedure
Transmitter
(Client)



Method
Start Server
Send data to Receiver
Record Statistics
Receiver
(Server)
PCATTCP
Software Utility

Created by Printing Communications
Associates, Inc. (PCAUSA)




Windows version of Test TCP (TTCP)
Bench-marking tool for TCP and UDP
Command-line based
Modified to:



Automate the testing process
Use handshakes between trials
Enhance UDP transfers
Different PCATTCP Trials
Same LAN
(inside Clarkson)
Same Host
(same computer)
Same Switch
(same lab)
LAN to Internet (Clarkson
to a Roadrunner service)
LAN to
LAN
(Clarkson
to SUNY
Potsdam)
Note: LAN stands for “Local Area Network”
Results
LAN to LAN
Percent Received vs. Packet Size
140
120
100
80
60
40
20
0
TCP
UDP
0
2000
4000
6000
8000
Percent Received (%)
Effective Throughput
(Mbit/sec)
Effective Throughput vs. Packet Size
100
90
80
70
60
50
40
30
20
10
0
TCP
UDP
0
10000
2000
4000
6000
8000
10000
Packet Size (bytes)
Packet Size (bytes)
LAN to Internet
Percent Received vs. Packet Size
140
120
100
80
60
40
20
0
TCP
UDP
0
5000
Packet Size (bytes)
10000
Percent Received (%)
Effective Throughput
(Mbit/sec)
Effective Throughput vs. Packet Size
100
90
80
70
60
50
40
30
20
10
0
TCP
UDP
0
2000
4000
6000
Packet Size (bytes)
8000
10000
Results
Same Switch
Percent Received vs. Packet Size
140
120
100
80
60
40
20
0
TCP
UDP
0
5000
Percent Received (%)
Effective Throughput
(Mbit/sec)
Effective Throughput vs. Packet Size
100
90
80
70
60
50
40
30
20
10
0
10000
TCP
UDP
0
2000
Packet Size (bytes)
4000
6000
8000
10000
Packet Size (bytes)
Same LAN
Percent Received vs. Packet Size
140
120
100
80
60
40
20
0
TCP
UDP
0
5000
Packet Size (bytes)
10000
Percent Received (%)
Effective Throughput
(Mbit/sec)
Effective Throughput vs. Packet Size
100
90
80
70
60
50
40
30
20
10
0
TCP
UDP
0
2000
4000
6000
Packet Size (bytes)
8000
10000
Conclusion

Performance of TCP vs. UDP?


UDP has higher effective throughput in many
common environments (6x better in the same
LAN; 2x better LAN to LAN)
TCP sometimes beats UDP though! (Same
switch, LAN to RoadRunner at large packet sizes)


Why? Lack of flow control in UDP
Outside a single LAN, UDP loss rates are
substantial (60% or worse)
Conclusions (con’t)



Within a single LAN is a sweet spot for UDP,
drop rates not excessive and lack of flow
control not a big deal (6x over TCP)
Outside same LAN, UDP can still perform
better than TCP but receive < 10% of packets
sent (i.e. flooding network to accomplish the
goal)
TCP is in all ways better on a single switch!
Future Plans



Use larger data sets (instead of 8 MB, 1 Gig)
Use our PCATTCP software on Wireless
technology
Port our PCATTCP version from Windows to
UNIX

Test across platforms
Acknowledgements



Ronald E. McNair Scholars Program
Dr. Jeanna Matthews, Clarkson University
The Computer and Technology Services at
SUNY Potsdam
Questions?
LAN to Internet
Effective Throughput
(Mbit/sec)
Effective Throughput vs. Packet Size
5
4
3
TCP
2
UDP
1
0
0
5000
Packet Size (bytes)
10000