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

e-mail client

TCP/UDP server

IP server

ethernetdriver/card

user X

SMTP

TCP/UDP

IP

e-mail server

TCP/UDP server

IP server

ethernetdriver/card

user Y

IEEE 802.3 standardelectric signals

English

CS454 (Computer Communication) Clarkson University, Summer 2002

Transmission Control Protocol (TCP)

Handshaking Reliable data transfer Flow Control Congestion Control

Hi thereHey there, I am ready for data

Sending DataI got it. Ready for more!

Connection-oriented service!

User Datagram Protocol (UDP)

No Handshaking! No Reliable data transfer No Flow Control No Congestion ControlSending data!

Sending data!Sending data!

Connectionless-oriented service!

Sending data!

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)

ProcedureTransmitter (Client)

Receiver (Server)Method

Start Server Send data to Receiver Record Statistics

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 Host (same computer)

Same Switch (same lab)

LAN to LAN

(Clarkson to SUNY Potsdam)

LAN to Internet (Clarkson to a Roadrunner service)

Same LAN (inside Clarkson)

Note: LAN stands for “Local Area Network”

ResultsEffective Throughput vs. Packet Size

020406080

100120140

0 2000 4000 6000 8000 10000

Packet Size (bytes)

Effe

ctiv

e Th

roug

hput

(M

bit/s

ec)

TCP

UDP

LAN to LAN

Effective Throughput vs. Packet Size

020406080

100120140

0 5000 10000

Packet Size (bytes)

Effe

ctiv

e Th

roug

hput

(M

bit/s

ec)

TCP

UDP

Percent Received vs . Packet Size

0102030405060708090

100

0 2000 4000 6000 8000 10000

Packet Size (bytes)

Perc

ent

Rec

eive

d (%

)

TCP

UDP

LAN to Internet

Percent Rece ived vs. Packet Size

0102030405060708090

100

0 2000 4000 6000 8000 10000

Packet Size (bytes)

Perc

ent

Rec

eive

d (%

)

TCP

UDP

ResultsPercent Rece ived vs . Packet Size

0102030405060708090

100

0 2000 4000 6000 8000 10000

Packet Size (bytes)

Perc

ent

Rec

eive

d (%

)

TCP

UDP

Effective Throughput vs . Packet Size

020406080

100120140

0 5000 10000

Packet Size (bytes )

Effe

ctiv

e Th

roug

hput

(M

bit/s

ec)

TCP

UDP

Same Switch

Effective Throughput vs. Packet Size

020406080

100120140

0 5000 10000

Packet Size (bytes)

Effe

ctiv

e Th

roug

hput

(M

bit/s

ec)

TCP

UDP

Percent Received vs . Packet Size

0102030405060708090

100

0 2000 4000 6000 8000 10000

Packet Size (bytes)

Perc

ent

Rec

eive

d (%

)

TCP

UDP

Same LAN

Conclusions Effective Throughput

UDP is usually higher 6 times better on same LAN 2 times better LAN to LAN

TCP is sometimes better 2 times better on same switch Slightly better from LAN to Road Runner (large packet sizes)

Efficiency TCP always has 100% UDP

Usually near 100% on same switch and LAN Usually less than 50% from LAN to LAN Usually less than 10% from LAN to Road Runner

Discussion Causes of lower throughput with UDP

UDP does not retransmit lost packets Minimal on same switch and same LAN Significant from LAN to LAN and LAN to Road Runner

UDP lacks flow control Has minimal effect on same LAN and switch Has significant effect from LAN to LAN and LAN to

Road Runner UDP has IP fragmentation

Has significant effect on same 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 vs. Packet Size

0

1

2

3

4

5

0 5000 10000

Packet Size (bytes)

Effe

ctiv

e Th

roug

hput

(M

bit/s

ec)

TCP

UDP