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 standard

electric signals

English

CS454 (Computer Communication) Clarkson University, Summer 2002

Transmission Control Protocol (TCP)

What is it? A protocol for data exchange Establishes a connection between two hosts

(computers) on a network Delivers data in order and retransmits lost data

Transmission Control Protocol (TCP)

Handshaking Reliable data transfer Flow Control Congestion Control

Hi thereHey there, I am ready for data

Here it isI got it. Ready for more!

User Datagram Protocol (UDP)

What is it? A protocol that allows for fast data transfer Does not establish connection (connectionless) Makes a “best effort” to transfer data

Not very reliable!

User Datagram Protocol (UDP)

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

Sending data!Sending data!

TCP vs. UDP

Stream-oriented Connection established

Good network citizen Congestion control Flow control

Reliable

Datagram-oriented Connectionless

Blasts Away No congestion control No flow control

Best-effort

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)

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”

Results

Percent Received vs. Packet Size

0102030405060708090

100

0 2000 4000 6000 8000 10000

Packet Size (bytes)

Per

cen

t R

ecei

ved

(%

)

TCP

UDP

Effective Throughput vs . Packet Size

020406080

100120140

0 5000 10000

Packet Size (bytes)

Eff

ecti

ve T

hro

ug

hp

ut

(Mb

it/s

ec)

TCP

UDP

Same Switch

Effective Throughput vs . Packet Size

020406080

100120140

0 5000 10000

Packet Size (bytes)

Eff

ecti

ve T

hro

ug

hp

ut

(Mb

it/s

ec)

TCP

UDP

Percent Received vs . Packet Size

0102030405060708090

100

0 2000 4000 6000 8000 10000

Packet Size (bytes)

Per

cen

t R

ecei

ved

(%

)

TCP

UDP

Same LAN

Results

Effective Throughput vs . Packet Size

020406080

100120140

0 2000 4000 6000 8000 10000

Packet Size (bytes)

Eff

ecti

ve T

hro

ug

hp

ut

(Mb

it/s

ec)

TCP

UDP

LAN to LAN

Effective Throughput vs . Packet Size

020406080

100120140

0 5000 10000

Packet Size (bytes)

Eff

ecti

ve T

hro

ug

hp

ut

(Mb

it/s

ec)

TCP

UDP

Percent Received vs . Packet Size

0102030405060708090

100

0 2000 4000 6000 8000 10000

Packet Size (bytes)

Per

cen

t R

ecei

ved

(%

)

TCP

UDP

LAN to Internet

Percent Received vs . Packet Size

0102030405060708090

100

0 2000 4000 6000 8000 10000

Packet Size (bytes)

Per

cen

t R

ecei

ved

(%

)

TCP

UDP

Conclusion

TCP in common environments Sometimes much slower (LAN to Roadrunner) Sometimes slightly slower (same LAN)

UDP lacks flow control Two hosts on the same switch Faster transfer

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