David,
There are plenty of books describing how IP packets are encapsulated in
Ethernet frames or ATM cells, or PPP frames. But I have not seen a book
describe how IP packets be carried in DS1, Fractional DS1, DS3, Fractional
DS3 signals. These signals are point to point, byte streams. I think IP
packets should be directly put on those TDM time slots and send from one end
point to the other. Can somebody answer my question or point out a book, web
site, or a standard so I can find the answer.
Sorry if I'm stating the obvious, but you can't just carry IP packets over
point-to-point links without some sort of framing, so you can tell where
one packet ends and the next begins. In addition to various
vendor-proprietary framing methods for IP over serial links developed over
the years, there have been two major methods standardized in the IETF to
frame IP packets over point-to-point links, SLIP (RFC 1055) and PPP (RFCs
1661 and 1662). SLIP is actually a "non-standard standard" (see the RFC
for more info). PPP was developed to address SLIP's deficiencies, some of
which are discussed in the SLIP RFC itself.
Cheers,
Andy