lmt filecopy

© 2009 www.thetechfirm.com

ExaminingA File Copy Comparison

Tony FortunatoNetwork Performance Specialist

The Technology Firm


Why???????

Many applications use different protocols to transfer data and you may need to explain why one is more efficient than others

For example, the latest version of the software may use a different protocol for a signature file update

The most common example of this methodology is when you have several choices to copy data and want the ‘fastest’ or more efficient option

When you need to document the behavior of a protocol or application, 2 laptops or desktops will do fine.

If performance was the goal, then you need similar hardware

Before you start capturing, you should establish naming conventions and directory structure, so you don’t have to figure it out as you got along. For example, the filename will be named after the protocol used for that test ftp, tftp, http – original trace files ftp_xfer, tftp_xfer, http_xfer – trace files of just the data transfer


Lab Setup

10.44.10.105 10.44.10.106

Server

HTTP

FTP

TFTPClient

Throughput BASELINE

In this example we ran IPERF and got 94.4 Mbps up and 96.3 Mbps down

This helped understand and illustrate if the PC’s, cabling and switches are working optimally

You now have a throughput baseline to compare against the protocols

100 Mbps 100 Mbps


Setting Up Wireshark To avoid getting other data in my trace I used the IP of the server as my capture filter


HTTP Copy

I always try to figure out the syntax to access what I want to test directly from the Start->Run command prompt

In this example, typing in the specific URL, will avoid generating traffic from my default home page, etc…

If there are prompts or logins, I capture the screen and ideally, the corresponding packet numbers, to properly understand delay

You would want to note which web browser you used, or if the transfer was handled by an application


TFPT CLIENT Various TFTP clients have different options available. I like this client since you can define the BLOCK Size to simulate what other clients

may be doing and left it at 512 Bytes, which is a common tftp client default.


FTP Client

I always try to use the command prompt since I get more control and know that response codes will be displayed back

Try to automate the process if you can As you dig deeper into any protocol you would want to note specific application

behavior For example;

Active or Passive List of commands sent, but not supported Does client try to log in with account defaults before using the client credentials Does software use multiple TCP connections


NOW WHAT!!!!!!!!!!!!!!!!!!!!!!!!!

OK, so you have 3 trace files of various lengths and characteristics Since this is the first (or possibly more) in the next series of Examining or baselining,

I will start with the basics Clean up trace files – Display filters Compare and explain Statistics Screen

The most important tip I can give is to have a plan or goal before you start the process

Resist the urge to capture packets ‘just because someone asked me to sniff the app’


Display Filter

1. I opened the FTP trace file

2. Went to Statistics -> Conversations and selected the TCP tab

3. I clicked on the Bytes Colum header to identify the port number used for the transfer

4. Right-Click on the first line Apply As Filter->Selected->A<->B

5. Now you have a filtered Trace File

6. Repeat the same steps with the other traces, keeping in mind that the tftp will be UDP, not TCP


Statistics Summary

I usually use all the following info under the Displayed header to start my comparison


Summarizing your Summary data

I find the most helpful way to compare anything is to use a table and/or chart

FTP HTTP TFTPPackets 1,554 2,138 4,086 Avg, Packet Size 726 543 302 Bytes 1,128,936 1,161,121 1,232,986

Copy Comparison

-

500

1,000

1,500

2,000

2,500

3,000

3,500

4,000

4,500

Pac

kets

& a

vg P

acke

t S

ize

1,060,000

1,080,000

1,100,000

1,120,000

1,140,000

1,160,000

1,180,000

1,200,000

1,220,000

1,240,000

1,260,000

Byt

es

Packets Avg, Packet Size Bytes

Packets 1,554 2,138 4,086

Avg, Packet Size 726 543 302

Bytes 1,128,936 1,161,121 1,232,986

FTP HTTP TFTP


Next….

If you found this helpful, let me know via the Comment Area, or email me at [email protected] with your suggestions

Possible next topics More detailed analysis between all three protocols HTTP protocol analysis FTP protocol analysis TFTP protocol analysis TCP Protocol analysis Calculating application read/write block sizes Using the;

IO Graphs Round Trip Time Graph Sequence Graph

How to make your own Graphs from a trace file


Thank You

ExaminingA File Copy Comparison

Tony FortunatoNetwork Performance Specialist

The Technology Firm

lmt filecopy

Technology

ftp trace file

xfer trace files

filtered trace file

http original trace

common tftp client default

data transfer

test ftp

common example