Cisco's AIP vs HSSI

Tue Oct 15 18:15:37 UTC 1996

> 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.

Quite believable.

> --Kent
> 
> We return to our regularly scheduled ATM tweaking program now in 
> progress.
> :-)

:)

Avi