t1's wan

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From: Steve Fabac <smfabac@att.net>
Subject: Re: dumb terminals connection to remote host via dsl?
References: <7juo7to7i90u4tj1ma4u0hltjhnll31o9a@4ax.com> <20010203174128.34363@tegan.com> 
Date: Mon, 05 Feb 2001 01:51:50 +0000

Tom Parsons wrote:
> 
> kewl enscribed:
> | a client's remote office connects to his home office unix server using
> | dumb terminals, multiplexers and a leased land line.  very expensive.
> | I've switched his smaller remote offices over to pc networks, and have
> | them connecting via dsl using telnet.  however, this last office has
> | many dumb terminals, and he doesn't want to switch to pc's all at
> | once.
> 
> So you replaced that with windoze pc's, probably connected bare-assed
> naked to the Internet and transmit company data and passwords unencrypted
> across the Internet?
> 
> Cheaper?  Maybe and maybe not for long.
> 
> | is there a device that will allow me to connect 6 or 8 dumb terminals
> | to a LAN which has a dsl internet connection, so the dumb terminals
> | can connect to the host in the home office? any recommendations?
> 
> Shouldn't be difficult to find, several prominent companys sell portservers.
> Digi, Specialix, Equinox for starters.
> --
> ==========================================================================
>  Tom Parsons            tom@tegan.com
> ==========================================================================

I have just moved a client from a 56K leased line with mux's and
dumb terminals and printers to a ADSL based VPN + Chase (Perle) IOLAN8+
terminal server ($1100). 

The VPN is provided by a pair of Watch Guard SOHOtc ($600 ea). 

The local (main office) network is 192.168.111.x with the Watch Guard
at 192.168.111.251. The remote network is 192.168.10.x with the
remote watch guard at 192.168.10.251. 

The IOLAN8+ is at 192.168.10.249. The Watch Guard routes all traffic 
for the 192.168.10.0 network over the VPN pipe to the remote office.

The IOLAN8+ has a daemon named ioland that is configured with a 
command iconfig to assign ttypXX's to ports on the IOLAND+ terminal
server. Iconfig creates /etc/ioland.cf containing the port associations
with the pseudo ttypXX's. 

On the client's system ports 2 and 3 are used for dumb terminals and
ports 5 and 6 are assigned to serial printers with hardware flow
control. 

# cat ioland.cf
-m -F chaseio 10005 ptyp60 ttyp60
-m -F chaseio 10006 ptyp59 ttyp59
-m -F chaseio 10002 ptyp62 ttyp62
-m -F chaseio 10003 ptyp61 ttyp61
#
 
>From /etc/inittab:
i61:2345:respawn:/etc/getty ttyp61 9600
i62:2345:respawn:/etc/getty ttyp62 9600

and lpstat -t | grep devices:
device for stl_raw_gencom: /dev/ttyp59
device for stl_matrix1: /dev/ttyp60

Running iconfig and choosing the "A" add function allows you to set up
printers or terminals on any of the IOLAN8+'s ports. The first ttypXX
port assigned is the highest ttypXX port on the system. Each port added
after that is the next lower ttypXX port. Since telnet ports are 
assigned from the bottom up, having the fixed ttypXX from the top down
insures that there is no overlap. 

In addition to the two dumb terminals and printers, the client added
two new Windows 98 pc's  at the remote office. I am using VisionFS to
provide Windows file sharing and the pc's mount the "Quotes on UNIX"
share as drive E: allowing me to set Excel and Word to default to the
E: drive for document storage. This keeps the quotes and customer 
contact letters on the UNIX server to be backed up at night. 

Equipment cost: $1240 for the two Watch guard SOHOtc's, $1100 for the
IOLAN8. $79/each end for SW Bell Enhanced ADSL with fixed IP addresses.

This replaces a 56K AT&T leased line at $1000/month for 2yr contract or
$1260/month for month by month. (Because of the delays in installing the
SW BELL DSL at both locations, we passed the leased line renewal date
and converted to the month by month so that the line could be terminated
once the DSL based VPN was running.)

The performance is good. The operators on the dumb terminals complained
because that have to adjust for the greater character delay with the
VPN then the lightning fast response of the terminals on the 56K stat
mux. But the delay is not worth $9600/year for the 56K leased line.

The only problem to date has been performance issues caused by a router
on the SW Bell backbone in St. Louis MO (it may not physically be in 
St. Louis but it identifies itself as: sbc-stlouis.130meg.ipcc.wcg.net
(64.200.228.14) when I ran traceroute). Running:
while true
do
date >>  /tmp/logping
ping  -q -c 60 -s 1000 64.200.228.14 >> /tmp/logping 2>&1
done
 
and letting that run overnight resulted in 0 to 100% packet loss
minute by minute over nine hours. The majority of the losses were in 
the range of 10 to 36%.  This problem persisted for two weeks before
SW Bell was able to fix it. 


                                       Steve Fabac
                                        S.M. Fabac & Associates
                                         816/765-1670

My Unix/Linux Troubleshooting Book

My Hard Truths about Easy Money Book

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