Solved

Need to determine flow of network traffic between 2 WinXP computers

Posted on 2007-12-02
11
236 Views
Last Modified: 2010-04-21
If I have a mapped network drive on PC1 pointing to PC2, then I download and select that mapped drive as the target how will the network traffic actually flow?

Will:
1. The router be smart enough to direct download staright to PC2?
2. Or...will PC1 still play a part in constantly having to direct traffic to PC2?

I'm basically making sure my network is as efficient as possible, so I can make proper workflow adjustments depending which one is the case.
0
Comment
Question by:exhaust
11 Comments
 
LVL 87

Accepted Solution

by:
rindi earned 500 total points
ID: 20394044
PC1 doesn't really care where the data goes. It just send out the data to the LAN. PC2 then checks what data on the LAN is meant for it and what data isn't. If you are using a switch, it will send the data to the PC on the switch that should also receive the data, while a HUB sends it to all attached PC's. That's what makes a switch more efficient than a HUB. Whether your router uses a switch or a HUB you'd have to check with the manufacturer.
0
 
LVL 19

Expert Comment

by:SteveH_UK
ID: 20394056
The computer initiating the download performs the connection to the outside world, through the router.  Then the file is downloaded to a local temporary folder on the same computer.  Once it has been fully downloaded, it is then copied over to the target system.

This is assuming that you are using Internet Explorer.  If you are using a different downloader then it is possible to save the file onto the networked computer as it is downloaded, but it is still the initiating computer that receives the traffic from the Internet.

In any case, the router does not have any decision-making part in this.  The computer makes the connection and starts downloading.
0
 
LVL 19

Expert Comment

by:SteveH_UK
ID: 20394057
So your (2) is the answer, except that PC2 is normally not involved until the download has completed.
0
 
LVL 7

Expert Comment

by:avatar-e
ID: 20394060
In fact, when you download anything with IE, the file always will pass trough the pc1. You can monitor actual network traffic from:

Start / run: perfmon.msc
0
 
LVL 6

Expert Comment

by:CasUK
ID: 20394106
I agree with avatar-e.

To clarify, if you have computers connected to a router, then any computer will download it itself first, regardless of where you are saving it.

If you download on PC1, Internet Explorer will download the file into the temporary files folder first. Once the download is completed, Windows will copy the file to the location that it is destined for, whether it be a mapped network drive or a local folder.

In fact, the easiest way to see this in action is to just download a large file (100MB or more).

Personally, when I want to download a large file, I always download to the local computer system first. If the file fails to copy across the network for whatever reason - IE isn't smart enough to realise that there has been a problem, and you have to start all over again.
0
Too many email signature updates to deal with?

Do you feel like you are taking up all of your time constantly visiting users’ desks to make changes to email signatures? Wish you could manage all signatures from one central location, easily design them and deploy them quickly to users? Well, there is an easy way!

 
LVL 3

Expert Comment

by:mhs85
ID: 20394110
1. The router be smart enough to direct download staright to PC2?  
The only involvement the router has in this process is transmitting the TCP Handshake and then the request to download certain data from PC1 to PC2.
2. Or...will PC1 still play a part in constantly having to direct traffic to PC2?
PC1 just hears the request from PC2 over the network from a certain IP address, and then it sends the TCP/IP packets over the network to the IP address that requested them.

So to answer your question, PC1 is not doing any "traffic directing." Rather, it is responding to a request made by PC2, which was transmitted to it via the router.
0
 
LVL 19

Expert Comment

by:SteveH_UK
ID: 20394127
mhs85, I'm not sure you are answering the question being asked. I believe that exhaust is trying to download a file from the Internet using PC1, but trying to save the file directly to PC2.

This is an issue at the application level, not layers 2/3, and so TCP handshake issues are really not relevant here.
0
 
LVL 3

Expert Comment

by:mhs85
ID: 20394136
Or, a more fun version: (I got a little bored...)

PC2: Hey everyone, I want to download stuff from some guy named PC1
Router: Okay, calm down PC2, I know that PC1's IP address is xxx.xxx.xxx.xxx, I will send your request to him.
Router sends following message to PC1: Yo PC1, listen, PC2 wants to download certain files from you.  His IP Address is aaa.bbb.ccc.ddd.
PC1: <Receives incoming message from Router>
PC1: Okay, so this guy at IP Address aaa.bbb.ccc.ddd wants these files. I will send the files over the network to that IP address.
Router: <Recieves incoming data from PC1, destination address=aaa.bbb.ccc.ddd>
Router: Sends following message to PC2: Yo, PC2, PC1 is sending you some stuff, prepare to receive the following stream of data
PC2: <Receives incoming datastream from network>
PC2 sends following message to PC1: Hey bro, thanks for the files, i got them
Router forwards message to PC1
PC1: <Receives incoming message>
PC1 sends following message to PC2: No problem bro, i'll talk to you later
Connection Terminated

Have a great night!
0
 
LVL 3

Expert Comment

by:mhs85
ID: 20394243
Oh wow. I completely mis-read the question, as evidenced by my last post.  My apologies!  My answer was with reference to 2 PCs communicating on the same LAN.  

You guys were right...PC1 would still be involved.  The router would never know to send the file directly to PC2 because you have given that directive on an application level, not on the IP/MAC level.
0
 
LVL 29

Expert Comment

by:Alan Huseyin Kayahan
ID: 20394360
Hi exhaust
     Application layers (Application,Presentation,Session): File transfer starts here. You open up internet explorer, request the file, presentation checks if data is readable, and session says "Start" between two hosts. In this case, remote host is where you download from and your local host is PC1. To learn why, you should get deeper.
     Network Layers: Here is where all communication with your destination which you will download from occurs. PC1 is the one who sends SYN not PC2, and the source IP is PC1's IP which is NATed through internet modem/router not PC2. PC1 is source in address translation/session state in modem/router not PC2. That would be spoofing if PC1 stated PC2's values as packets source. So "The router be smart enough to direct download staright to PC2" statement will be wrong. This is not about being smart or not.
    When you choose a mapped drive as destination, the file being downloaded will take a temporary resource from PC1 which means PC1 originally hosts the file, doesnt matter if it is downloaded via IE or not. The relation between PC1 and PC2 is just a file copy operation, which is another connection that has PC1 as source and PC2 is destination. And from this point, please follow rindi's useful post to learn what is going on between PC1 and PC2 in LAN.

Regards
0
 
LVL 3

Author Closing Comment

by:exhaust
ID: 31412274
Short, sweet and to the point.
0

Featured Post

Too many email signature changes to deal with?

Are you constantly being asked to update your organization's email signatures? Do they take up too much of your time? Wouldn't you love to be able to manage all signatures from one central location, easily design them and deploy them quickly to users. Well, you can!

Join & Write a Comment

For both online and offline retail, the cross-channel business is the most recent pattern in the B2C trade space.
Possible fixes for Windows 7 and Windows Server 2008 updating problem. Solutions mentioned are from Microsoft themselves. I started a case with them from our Microsoft Silver Partner option to open a case and get direct support from Microsoft. If s…
This video Micro Tutorial explains how to clone a hard drive using a commercial software product for Windows systems called Casper from Future Systems Solutions (FSS). Cloning makes an exact, complete copy of one hard disk drive (HDD) onto another d…
Get a first impression of how PRTG looks and learn how it works.   This video is a short introduction to PRTG, as an initial overview or as a quick start for new PRTG users.

743 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question

Need Help in Real-Time?

Connect with top rated Experts

10 Experts available now in Live!

Get 1:1 Help Now