[OT] Pointers to online material on OSI Layer 2/3 Protocols

Hi,

I apologize for this slightly OT post. I am looking for detailed
information on Layer 2/3 protocols such as HDLC, SLIP, etc, as well as the
underlying hardware (switch, bridge).

Google showed up some results, but there was no particularly good Primer I
could find.

Any pointers/suggestions on the above (as well as a more appropriate
newsgroup to post to, if any) would be highly appreciated.

Thanks
Abhinav


Abhinav