🚀 go-pugleaf

In article <663@starfire.MN.ORG> john@starfire.MN.ORG (John Lind) writes:
   SLIP and PPP are inherently ASYNC protocols, but you have picked a
   SYNC physical transport system.

You're right, SLIP is typically used only on systems where each end
thinks it's talking async.  But one of the design goals of PPP was
that the same protocol be usable over either sync or async
connections.  This goal introduces some schizophrenia, of course...
PPP addresses some deficiencies of SLIP by (e.g.) being able to work
through non-transparent async modems, such as those using XON/XOFF
flow control.  And while the high-speed sync router vendors still
support their own proprietary sync inter-router framing, they also
typically support PPP for interoperability with routers from other
vendors (and non-router boxes that can speak sync PPP, such as UNIX
systems running our PPP product) that may be lurking at the other end
of the wire.

   ...sync connections tend to be dedicated, while async connections
   are dial-up... Since you are talking CSU/DSU, you aren't talking
   async or dialup at all.

You point out some exceptions, such as that some sync connections have
dialup attributes (e.g. ISDN); others have described CSU/DSUs with
async DTE interfaces.  But yes, in general most dedicated lines run
sync PPP and most dialup lines run async PPP.

   With your synchronous dedicated line, there ISN'T anything quite
   like PPP or SLIP that will use it, 

How about running synchronous PPP?

   You don't need PPP and you don't need SLIP to use that line.  You
   need bridge/router software/hardware.

Routers typically talk sync PPP to other routers.  If you can talk
sync PPP on your box, the router won't be able to discern that you're
not another router.

   And, in case you haven't looked at bridge/routers lately, they have
   a lot more horses under the hood than your 486 box in most cases,
   and sophisticated dedicated hardware to assist in their complex and
   time-critical job besides.

For a small network (e.g. a home), a machine with the horsepower of a
PC/XT (or that much leftover horsepower on some other machine) can
manage the packets-per-second requirements, and keep a 56K line full.

   You can get bridge/router cards to plug into your 486 PC/ISA/EISA
   bus, I hear, but I don't know of them and I haven't used any.

Earlier inquirers on this newsgroup have searched for sync PPP
software for a DOS system, and the accompanying hardware interface.  I
don't know what they turned up, but I recall they were disappointed.

At least two companies (Brixton Systems and Morning Star Technologies)
sell PPP software for UNIX systems that can be run async over the
native serial ports, or sync over the hardware they'll sell you.  But
neither company (so far as I know :-) makes a DOS PPP (yet :-), nor a
sync DOS PPP, nor the hardware you'd need to run sync PPP on a PC.