On Tue, 19 Mar 1996, Hume Smith wrote:

> > As long as your not expecting to get the look & feel of a 56k leased line
> > by bonding two 28.8k modems together, then it should be possibly.. But
> > keep in mind, a 56k leased line will be MUCH quicker than two bonded
> > 28.8k analog modem lines..
> 
> why so?  less protocol overhead?  fewer glitches and retries?
> how does it (usually) compare in cost-second/bit ? :)
> 
The deal is basically somethign like this. Bonding and load balancing 2 
28.8 links will give you a THEORETICAL thruput of 56kbps, however, there 
are several differences between 56kbps leased line and bonded modems. It 
has mostly to do with the signalling methods employed in the frame relay 
spec (frame relay being what I consider 56k leased line). Frame relay 
uses purely digital transmission to send data. This dramatically speeds 
things up because you are talking straight digital vs. the 
digital->analog->digital that you get with a modem connect. The use of 
digital signalling lowers the line latency to bring it into the range of 
milliseconds instead of the seconds of latency that you can get with an 
analog transmission scheme. I'm not much of an authority on this one, so 
please, correct me if I'm wrong. I'm learning this all right now 
(actually reading a very good book on frame relay that i picked up today. 
it's "The Basics Book of Frame Relay" from Motorola/Codex 
Press...EXCELLENT little 50page book, the whole series is great 
actually). Hope that helps you a little. Maybe I can offer something a 
bit more substantial in a few days after I have gotten a little more 
reading done on the topic.

rob

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