Cisco has generally good docs.
http://www.cisco.com/univercd/cc/td/doc/cisintwk/ito_doc/atm.htm
There's also some ciscopress books about ATM that probably explain it
in more detail.
Just because you're rooted in a corporate, ethernet/IP network
background, doesn't make that a "normal" network :) Ethernet is just
one of many, not the first, not the last. Its certainly the most
common in a corporate/home environment for networking now-a-days though.
ATM is sometimes referred to as layer 1.5. It is closest to being on
the same level as Ethernet (yes, you can have a pure ATM only switch
or a combination ATM & ethernet switch, or an ATM to Ethernet router).
ATM is transported over many types of media. There's an ancient copper
transport at 25Mbps. You can do it over T1/E1, T3/E3, SONET speeds.
You can run IP over ATM, but the switches can make more intelligant
decisions than Ethernet switches generally can.
Now-a-days, its not so much as everybody trying to fit any and every
network protocol into ATM, but more technology developed to use ATM.
Alternative view: Aside from its use between ADSL "modem" and DSLAM, and
some use between DSLAM and ISP, ATM is dead as a doornail.
For LANs, ATM *is* dead as a doornail. RIP.
Steinar Haug, Nethelp consulting, sth...@nethelp.no