Where is the buffer in mac layer?

If I send data to other node.

================================================== =======
data => TCP packet => IP packert => MAC FRAME => PHY

||
V
internet

||
V

destination

================================================== ===

in this case, I want to know who control the mac frame.
1) if ip packet is divided into mac frames, where is the mac frames' buffer?
OS or NIC device driver?


--

-------------------------------------
What I believe is what I can do.

http://opal.kaist.ac.kr/
Choonho Son @ Programming Language Lab. KAIST

"Choonho Son" <(E-Mail Removed)> wrote in message news:<c67tcd$ufq$(E-Mail Removed)>...
> If I send data to other node.
>
> ================================================== =======
> data => TCP packet => IP packert => MAC FRAME => PHY
>
> ||
> V
> internet
>
> ||
> V
>
> destination
>
> ================================================== ===
>
> in this case, I want to know who control the mac frame.
> 1) if ip packet is divided into mac frames, where is the mac frames' buffer?
> OS or NIC device driver?

If I understand your question -- where is the physical/wire framing
performed? -- you'll see that it has to be at the driver/interface
layer as the above layers have no knowledge of the _kind_ of hardware
running at the physical level. That's the whole point of the TCP/IP
stack -- seperate the upper layers from the hardware (ethernet, token
ring, FDDI, ATM, HDLC, ISDN, frame relay, PPP, etc.).

Each lower layer encapsulates what the upper layer handed to it, then
passes it on to the next lower layer. Finally, a device driver
"drives" the hardware that places the _signal_ on the wire (sometimes
it is a "frame" and sometimes it's a "cell" and sometimes it's
something else).

"Buffers" at the lowest levels will depend on the operation at hand --
tx'ing or rx'ing -- and the kind of hardware/protocol on the wire.

This is a _very_ general explanation of what goes on.

hth,
prg
email above disabled