While this is certainly true, HDLC is a point-to-point protocol
and not a network protocol, like frame relay, SMDS or ATM. And
HDLC itself isn't quite enough, IMHO, you really need PPP.
We run PPP on all non-frame-or-smds and less-than-DS3 links so that
the customer (or ourselves, if it came to it) could switch to non-
Cisco gear instantly.
But we usually leave most cisco-cisco high-speed links at HDLC.
My impression is that HDLC was the same efficiency - or moderately
more so - than PPP.
For what do feel that one *really* needs PPP?
Or, to put it another way, maybe we're talking about different things.
I'm talking about the HDLC *point-to-point* *network* protocol, as
implemented by Cisco, not HDLC the low-low-level point-to-point protocol.
And the efficiency lost to ATM is not 40% as often claimed on this
list, but rather it is 12% less efficient than PPP for TCP.
10% is the cell header overhead and 2% is due to modulo 48 padding,
given actual traffic at FIX West as measured by kc at NLANR.
We return to our regularly scheduled ATM tweaking program now in