🚀 go-pugleaf

In <1992Aug7.224514.12152@parc.xerox.com> jellinek@Xerox.com (Herb Jellinek) writes:


>Hi,
>	After much running around and many meetings with 'experts,' I am still without a clue as to the best way to connect a 486 PC at my home to the Ethernet here at work.  I know that I want to run PPP, and I know that I want to run it as fast as I can.  The phone line decision is made: a PacBell 'ADN' DS-0 circuit, running at 56Kbps.  Similarly, I've identified a few likely CSU/DSU vendors that'll handle 56Kbps sync from/to a data source/sink.  From my perusing the literature, FTP Software will soon begin se



l

Care to give us the details on the DS-0 circuit, Installation cost,
ongoing cost. How about the CSU/DSU vendors? Names, prices, etc.

>ling a PPP package that also supports Novell protocols, which is also a requirement of ours.  (I assume it does some sort of IP tunneling.)

I believe that the just released 2.1 generic kernel includes a ppp
packet driver and the associated stack.

>	Here are my questions, which no one I've found seems able to answer.  What sort of serial hardware will I need on the home 486, if I want to talk to the CSU/DSU (and thus the phone line) at 56K, synchronously?  Will the normal sort of PC comm port do the trick?  (Is there such a thing?)  (I'm a Sun/Unix guy starting the painful transition to PC's and Windows.  Forgive my naivete, please.)  I would ask these questions of the people at FTP, for instance, if only we were permitted to speak with someone who 



h
>as, shall we say, some technical background.

Try jamie@ftp.com, he has helped me with some sticky slip porblems in
the past.

The FTP packet driver is called ppp16550, which leads me to believe
that they are expecting to drive a standard RS232 interface. The 16550
likely refers to the NS 16550 AFN Uart which has internal fifos which
cut down interrupt frequency. You only really need this is you are
running a multitasking environment such as Windoze or DesqView[/X]..
Look for a serial card with a 16550AFN on it or a socketed one so you
can order the chip and then install it yourself. Note, FTP inc. have
told me that some portion of el-cheapo async pc cards don't have the
necessary signal lines to toggle the 16550afn fifo's. There are some
utils on simtel and it's mirrors to test the 16550afn and to toggle it
on and off. It is much cheaper to retrofit an async card with a
16550afn than to but one specially equipped..

PK
--
Phil Kemp, Systems Engineer         Voice:(403)-233-2815
CONVEX Computer Canada Ltd.           Fax:(403)-261-2029
Calgary, Alta.                  Internet:kemp@convex.com

In article <1992Aug7.224514.12152@parc.xerox.com>, jellinek@Xerox.com (Herb Jellinek) writes:
> 
(first off, please limit your output to lines of less that 80 characters
if you want all possible people reading it to bother answering) 

The existing ASYNC port on any pc is a darn site cheaper than any SYNC
one you might have to buy, and you won't have software hassles. 

That port can easily go to 57.6kb or 115.2kb ASYNC, and will do so
reliably if you use the National NS-16550-AFN uart in your serial i/o
card. The uart will cost $10 - $15, just DO IT. 

On a DDS-II (aka BDS, or in CA it is called ADN) circuit you normally
only get 56kb sync. There are MANY CSU/DSUs out there that can do ASYNC
as a side benefit, but most stop at 19.2, a few go to 38.4, and even
fewer go to 57.6 (with the async start + stop bits stripped the
remaining real data easily fits on the 56kb sync channel). 

Earlier generations of CSU/DSUs all ran ONLY at whatever line speed you
ordered. Newer ones can often rate adapt to lower speeds from higher
ones. In many areas, a DDS line is the same price regardless of speed,
but to change the speed costs hundreds of dollars or even a whole new
circuit install (try $1000 for both ends of a LOCAL DDS install in NYC).

Getting a CSU/DSU that works at the fastest (56kb or 64kb) rate
available, but that will rate adapt downward and/or convert to async is
the best strategy. 

One company claims to have a 57.6kb async CSU/DSU. The also have a pricy
adapter for any SYNC CSU/DSU to make it run ASYNC at 57.6. In fact their
ASYNC CSU/DSU is really a classic (generations *old*) Case-DATATEL - NOW
known as Dowty - CSU/DSU that they oem and stuff their card into. They
also claim a patent on their strategy - if anyone really cares, I cam
probably dig out the number. 

They want $1500. OUCH!! And that CSU/DSU they oem is old enough so that
it runs at the speed you ordered the line at ONLY. I won't even bother
you with their name. 

One of the highest tech manufacturers is Adtran. You almost never hear
of them because they mostly sell to telcos and OEM customers. Their CSU
II AR does all sort of tricks, even does switched 56 dial backup!, but
only does 19.2 ASYNC rate adapting down from 56 (or from a 19.2 SYNC DSS
line, of course). It does all the lower speeds, 19.2, 38.4, 56, and 64
in sync mode and can support secondary channel for all speeds except
64kb where there is none possible. They support all speeds on v.35 and
rs232 connections. The sec channel has its own rs232 port. This unit
lists at $729. It is a *SUPER* unit.

They have a newer model in the works that has more features but has been
reengineered (a new ASIC cuts out a daughter card), and with competition
out there, may not cost any more than the current model. The new one
definitely does 57.6 ASYNC and does so without any patent violations. 

Their new one is actually in production for some unnamed OEM customer (I
suspect NEC - see below - but am not sure). The version of it with their
own name on it is probably a few months away. Adtran is at 800-726-8663
- so says the back of a manual. 

BAT has some very low cost CSU/DSUs. They have one that does 38.4 async.
If you get discouraged when you first see one, realize that they do work
well and are used in some very reputable networks. I think styling was
not an important issue with them... 

NEC has a new model N6450 (boxed) I6450 (card cage 1 unit per card)
I6452 (2 per card) CSU/DSU that claims 57.6 async. That boxed one has a
list of $995. 1.800.222.4NEC ext 1277. 

At the lower speeds (not 57.6) there are assorted traditional
SYNC<->ASYNC adapters out there. Several brands are all probably made by
RAD, but there are others. This is not the route I personally would go,
but it may be of interest to someone. 

Want an inexpensive termial server that speaks SLIP/TCP-IP/LAT ? Look at
DEC's new DS700. Even in the 16 port version with less than full modem
leads, I think it has more modem lead type functionality than the cisco
MGS box sized Trouters I have seen. The 8 port version has FULL modem
lead control. This DEC box does 57.6 and 115.2kb. That makes it a good
choice for modem connections running 4:1 compression on top of 14.4 or
higher, where 38.4 wastes speed. 115.2 is even fast enough for
compression on top of the coming v.fast modems. 

The 16 port one lists for 3995 I think, but a dealer here in Cambridge
claimed to have some new ones at $2400 (Eli's for those that care). 

If anyone knows of other CSU/DSUs at good prices that do 38.4 or better
57.6, please let me know. 

(no affiliation with any of above)

In article <1992Aug11.031705.39985@camb.com> bruce@camb.com (Barton F. Bruce) writes:
>Want an inexpensive termial server that speaks SLIP/TCP-IP/LAT ? Look at
>DEC's new DS700. Even in the 16 port version with less than full modem
>leads, I think it has more modem lead type functionality than the cisco
>MGS box sized Trouters I have seen. The 8 port version has FULL modem
>lead control. This DEC box does 57.6 and 115.2kb. That makes it a good
>choice for modem connections running 4:1 compression on top of 14.4 or
>higher, where 38.4 wastes speed. 115.2 is even fast enough for
>compression on top of the coming v.fast modems. 
>
>The 16 port one lists for 3995 I think, but a dealer here in Cambridge
>claimed to have some new ones at $2400 (Eli's for those that care). 
>

FYI:

The new Cisco 16 port terminal server ( 516-CS ) supports full modem
control and lists for $3995. It does telnet,rlogin and tn3270. Supports
PPP/CSLIP/XRemote and full routing. You can get an option for LAT. 
However, the top speed is 38400 . The ASM model does 57600.

I think the Livingstone PortMaster (sp?) is another cheap terminal
server with most of these features. It lists less than the Cisco

--pushpendra

In article <kemp.713460871@convex.convex.com>, kemp@convex.com (Phil Kemp) writes:
> In <1992Aug7.224514.12152@parc.xerox.com> jellinek@Xerox.com (Herb Jellinek) writes:
> 
> 
> >Hi,

Well, I was going to include quotes from the original article, but I ran
into a line-length problem.  Not to pick on you, Herb, but how can a
fellow who is a Unix-type person treat news like a word processor?

Anyway, as I understand it, you have made incompatible decisions.  SLIP
and PPP are inherently ASYNC protocols, but you have picked a SYNC
physical transport system.  Boom!  Barking up the wrong tree.

Though nothing enforces this approach, the general way things have been
done is that sync connections tend to be dedicated, while async connections
are dial-up.  There are exceptions, and most of us have seen or own 2400bps
and 1200bps modems that will do synchronous over dial-up, or which will
do async over leased lines, but in the really high-speed world, the
SYNC/dedicated ASYNC/dial grouping is essentially the unwritten law.
Since you are talking CSU/DSU, you aren't talking async or dialup at all.

Now that we move into the WAN world, the separations become even
stronger, though there is no inherent technical reasons for them.
Let me state that more clearly.  It is not a trivial change.  There
are inherent technical reasons why an async protocol won't work on
a sync line and vice versa, but there are no inherent technical reasons
that a given protocol had to be implemented for a given serial link
type -- they just tended to follow the modem industry lead: dialup
is async (and intermittant connectivity), dedicated is sync (and
fully connected).  With your synchronous dedicated line, there ISN'T
anything quite like PPP or SLIP that will use it, without putting a
stat mux or some similarly ridiculously complex and hardware intensive
solution on both ends.

You don't need PPP and you don't need SLIP to use that line.  You need
bridge/router software/hardware.  Either that or scrap the synchronous
connection and go dial dialup V.42bis.  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.

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.  These cards
pretty much just use the bus and enclosure for cooling and power.
You would STILL need some sort of network connection to talk to the
bridge/router.

Let's draw a picture:

Ethernet at work: ~============o============o===============oT
Cable taps*:                   |            |               |
	 		     -----        -----           -----
MAU/AUI*:                    |MAU|        |MAU|           |MAU|
			     -----        -----           -----
Transciever cables*:           |            |               |
                       --------------  -----------------  ----------
		       | Bridge or  |  | HOST 1        |  | HOST 2 |
		       | Router or  |  | w/SLIP or PPP |  ----------
		       | both       |  -----------------
		       --------------    |  Async line/standard port      
	V.35 or RS232 sync line |      ---------
			   ---------   | Async |
			   |CSU/DSU|   | modem |
			   ---------   ---------
	leased/dedicated line ||          ||     PSTN (Public Switched
			      ||          ~~     Telephone Network)
			   ---------      ||     I.e. dialup
                           |CSU/DSU|   ---------
			   ---------   | Async |
	V.35 or RS232 sync line |      | modem |
		       -------------   ---------
		       | Bridge/   |     | Async line
		       | Router    |   -----------------------------------
		       -------------   | Home System 1 running TCP/UDP   |
	Transciever cable* |           | via SLIP or PPP routing through |
			 -----         | HOST 1 for all other access     |
	MAU/AUI*	 |AUI|         -----------------------------------
			 -----
	Tap*		   |
	Ethernet at home  To====oT
	Tap*                    |
			      -----
	MAU/AUI*	      |MAU|
			      -----
	Transciever cable*      |
	      ---------------------------------------
	      | Home System 2 w/ethernet controller |
	      | for TCP/IP communicating as a peer  |
	      | with HOST 1, HOST 2, and other IP   |
	      | devices locally and at work.        |
	      ---------------------------------------

* These items may be bundled into the network device, almost certainly
  for 10baseT, and often for ThinNet.  For 10baseT though, you need
  a hub.  Tradeoffs, always tradeoffs!

For Home System 2, the WAN link is "transparent" if the Bridge/Routers
are strictly bridges, or routed if they are routers.  Some savings are
clearly possible if the work network already has a router or bridge
with a serial line/WAN port available.

We just installed a setup much like "Home System 2" for a client,
except that they also had a LAT/IP gateway on the "home" side, so the
local LAN had three devices rather than the trivial two shown here.

I wish you all the luck in the world.  If you find what you are looking
for, such information would be very enlightening to me, obviously.
-- 
		   John Lind, Starfire Consulting Services
E-mail: john@starfire.MN.ORG		USnail: PO Box 17247, Mpls MN  55417

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.