Network Card Activity

Hi all

Here's a basic question about all network cards.

At what point of time, after a PC has booted up, does the network cards on that PC become active.

What I am looking for is whether it becomes active i.e is it just after the BIOS has finished it's work and handed control over to the boot loader, or is it when basic I/O files of the OS has been invoked by the OS loading up itself?

My view is that a NIC becomes active only after certain basic services of the OS has started running after PC boot up, but not before that.

Reason for my query is that, someone has alleged that he managed to RDP/VNC to a computer which was stuck on bootup sequence trying to decide whether it wanted to boot from an USB device or the default HDD. I have refuted his claim, but will need to strengthen my argument for my opinion.

Cheers

Hi,

Yes, that someone is right.

Read the following although it is not give much info but it will solve your doubts.

Remote Installation Services boot disk

Updated: January 21, 2005

Applies To: Windows Server 2003, Windows Server 2003 R2, Windows Server 2003 with SP1, Windows Server 2003 with SP2

Remote Installation Services boot disk

The Remote Installation Services (RIS) boot disk is used with client computers that do not have a remote boot-enabled ROM. The boot disk simulates the Pre-Boot eXecution Environment (PXE) boot process for computers that lack a formal remote boot ROM. For more information about the PXE boot process, see PXE architecture.

The boot disk is analogous to a boot ROM, which uses the floppy drive to install the operating system from the RIS server. The remote boot disk-generating utility (Rbfg.exe) is located in the following folder:

\\Server_name\REMINST\Admin\I386\Rbfg.exe

The boot disk must be placed before the hard disk in the boot sequence in order for the boot disk to work.

To use the remote boot disk on a client computer that does not have a remote boot-enabled ROM, insert the disk into the disk drive and start the client computer. The client computer must have a Peripheral Component Interconnect (PCI)-based network adapter from the list of specific adapters supported. To determine which network adapters RIS supports, use the boot disk-generating utility. For more information, see Create a remote boot disk.

technet.microsoft.com/en-us/library/cc784106%28WS.10%29.aspx

Regards,

Rizin

This is an interesting question. I've seen some machines where the lights on the NIC are lit and flashing when the machine itself is switched off but still connected to the supply. And, if you think about it, the NIC must be active in some way when the computer is off otherwise Wake On LAN could never work

Hi rizin,

Went through the entire technet document.

Only one catch to this explanation. That PC is running Windows XP SP 2

Also, the catch is since this PC has a valid OS running, with a operational conventional ROM. This means that this PC stuck on trying to find a valid boot drive, has not loaded any drivers whatsoever, and is looking for a valid source. This would imply that device drivers for networking etc would not be loaded.

Bishop, WOL works on the principle of an active network card looking for a 'magic packet' which triggers the card to send a 'wake' signal to the system board. So the NIC is always active.

The situation I described was where the PC could not detect a valid drive which houses a valid OS. On a different note, I confirmed that WOL was not enabled on that PC as the motherboard does not support it.

Cheers

My view is that a NIC becomes active only after certain basic services of the OS has started running after PC boot up, but not before that.

versus:

Bishop, WOL works on the principle of an active network card looking for a 'magic packet' which triggers the card to send a 'wake' signal to the system board. So the NIC is always active.

For clarity, I suppose the difference here is whether the NIC, BIOS and motherboard support WOL and, if they do, whether it is enabled. The meaning of 'active' is also key; In the first quote I think you're saying you mean active in terms of the network drivers and protocol stack being loaded up so that the NIC functions fully as an addressible network endpoint. And in the second quote the NIC is active because it has power and is sitting waiting for a specially crafted MAC frame, but no more than that.

Have I got it?

Hi Bishop

The term 'active' in both context is that:
1) network card has power
2) network card has protocol stack loaded
3) network card is in a position to accept data and decipher it, and is able to take action based on packet content.

Cheers.