A question about netwrok traffic | Tech Off

Shrage
Let's Tallk

If a network card has 1 Gb per second capebility, and i send a 2 gb file, will the transfare take 2 sec? my question is will the system use the full capacity of a network card when transfering? because i have never seen my netwrok trafic percentage should go up, only when transfaring multiple files, but never on a single file.

PerfectPhase
"This is not war, this is pest control!" - Dalek to Cyberman

Network card speed is measured in gigabits

File is in gigabytes.

Therefore a 2 Gigabyte file will take close to 16 seconds (plus a bit extra for the IP+TCP+SMB overhead).

Also depends a lot on you disk, for example an average SATA-2 7200rpm drive has a Media transfer rate of about 800Mbit/s so it would not be able to flood a 1Gb card, espically if it's doing something else at the same time.

julianbenjamin
Giggity

Gigabits per second (what the network card speed is measured in) and Gigabytes per second are different measures. The first is about 10 times slower than an actual Gigabyte. For example, a 10Mb/s card will support 100k transfer per second.

That being said, you'd need cabling that supports the gigabit over ethernet (cat6), and at most, you'll get 100 Megabytes per second.

julianbenjamin
Giggity

damn! posted a little late

koorb

I think four seconds because network cards normally run in full duplex mode so half the bandwidth is reserved for sending and the other half is reserved for receiving. Although I am no network expert so I could be wrong.

mrsith

   Where are you sending the file to? Are you going over the local network or the Internet? Are you using xcopy, FTP, HTTP, ssh, etc? What is the speed of the Internet connection (if going over the Internet) or the network card of the receiving machine? What kind of network is on the receiving end? All of these questions (and more) effect the transfer rate over a network. If you are sending locally and over TCP/IP then you have the Ethernet protocol overhead, the TCP and IP overhead, and any overhead from the application layer protocol you are using for transfer (Windows file sharing, FTP, HTTP, etc) as well as the overhead of your switch if you have one.
   If you are going over the Internet then you have the added overhead of all of the routers and the links between those routers.
   Additionally, any bottleneck on the receiving side (network card speed, internal network configuration, hard drive speed, etc.) could slow down your transfer as well. That doesn't even include the possibilities of packet collisions on an Ethernet network which if you have a busy network could be extremely detrimental to transfer speed.

cheong

Network protocol does matter. Even if you use xcopy throught Network Shares, two PCs connecting through IPX/SPX(the protocol used in NT4) will have higher transfer rate than TCP/IP on a reliable network. (Due to larger packet size and smaller header overhead) Smiley

mrsith

Actually, IPX/SPX was primarily used when talking to a Novell Netware server or client. It was not the primary protocol on NT4. TCP/IP and/or NetBEUI with NetBIOS were the most widely used protocols on NT4. TCP/IP was used for routed networks and NetBEUI for unrouted networks (since it isn't a routable protocol).

W3bbo
The Master of Baiters

julianbenjamin wrote:
Gigabits per second (what the network card speed is measured in) and Gigabytes per second are different measures. The first is about 10 times slower than an actual Gigabyte. For example, a 10Mb/s card will support 100k transfer per second.

That being said, you'd need cabling that supports the gigabit over ethernet (cat6), and at most, you'll get 100 Megabytes per second.

I've got a 2Mbps internet connection and get 250KBps downstream, so you're a little off there Wink

In my experience, your top throughput speed is about 75% the advertised speed, in my case it's mostly 66%.

My home LAN is 1 Gbps, over Cat5e cable I get about 66-70% throughput to other Gigabit clients, and about 60-66% throughput to 100mbps clients.

Shrage
Let's Tallk

Thanks all,
My main question was, if there is such a think as buffer, which will not allow to transfare the whole file at once. For example Internet Explorer will never upload files using the full capacity of the card, it has a very litle bufer size by default.

cheong

Shrage wrote:
Thanks all,
My main question was, if there is such a think as buffer, which will not allow to transfare the whole file at once. For example Internet Explorer will never upload files using the full capacity of the card, it has a very litle bufer size by default.

All reliable network protocol have some buffers by design, because you just won't know "when there'll be traffic congestion on the other end of network". When the sender received certain signal that the other end has reached it's speed limit, the transfer rate slows down and data begin to queue in the buffer.