Getting Connected with ISDN
You can now get on the Internet faster with an ISDN connection from BCTel.
You can either have a permanent connection, or a dialup connection,
operating at up to 128kbps. To do this trick you need an ISDN modem or router.
One possibility is the P-25 or P-50 from Ascend.
The setup looks like this:
Anything with a configurable Ethernet port should work - DOS/Windows with
tcp/ip stack, X-Terminal, Unix, WinNT, etc. The kit consists of an Ascend Pipeline 50 (P-50)
router, cables and power supply. The P-50 combines the functions of a
network termination, modem and ip router, so that it can be used to connect a
small business or home LAN to the Net. The P-25 is similar, but has no routing capability.
The P-50 acts as a gateway for various protocols, including IPX and TCP/IP, so
that it may be used to connect Novell LANS as well as IP based LANS. The
bandwidth is guaranteed, so that using a pair of these routers to temporarily
connect two branches of an organization for conferencing or data sharing may
be a better bet than relying on the vagaries of the Internet.
The P-50 may come pre-configured, but to check operation and possibly to fix
problems a terminal or emulator may be connected to its DB9 serial port.
When configured for dialup, the modem dials in about 1 second when there's
a request. Once connected, it stays up until there's no activity, then
times out after 30 seconds (configurable). When there's no connection, ip packets
from outside cannot open a connection, though the ISP can dial through
and reconfigure the modem (and access your machine if you let them).
Configuration
For single-platform use, you set up a little LAN with 2 members, and the modem defined as a gateway,
like so:
eth0 inet addr nnn.nnn.nn.77 Bcast nnn.nnn.nn.79 Mask 255.255.255.252
Destination Gateway Genmask Flags Metric Ref Use Iface
nnn.nnn.nn.76 * 255.255.255.252 U 0 0 0 eth0
127.0.0.0 * 255.0.0.0 U 0 0 0 lo
default nnn.nnn.nn.78 * UG 0 0 2 eth0
with appropriate DNS addresses, etc. as supplied by the ISP.
The ISDN phone jack is a regular 4-pin modular jack using only the inner
pair - just like a normal line. Installing the jack yourself and letting
BCTel hook up the demarc box may not save you any money, but may be easier on
your schedule. It does, however, have 2 phone numbers - one for each B
line. One test possible with the P-50 (if you have the password) is
a loopback from one line to the other.
Performance
It's not Ethernet. It is, however,
about as fast as international Internet, so for running Netscape to the US
the throughput is comparable to a platform on a T1-connected LAN. For a dialup
connection, the ISP may not want
people to tie up lines (by doing a continuous ping, for instance), so
if you are in a Telnet session and stop to think for a bit there's a bit
of a delay before the system reconnects. If I leave an idle Telnet session up
for a long time the far end disconnects it after a while, so edits, etc.
should be closed if you step out for more than a few minutes.
The X-11 performance is pretty good, considering:
Server Client xStones Transport Server Software
------ ------ ------- --------- ---------------
NCD hmx SunOS 307647 ethernet NCDhmx V3.2
NCD SunOS 131323 ethernet NCD 11.3002
486-66 SunOS 92016 ethernet XFree86 11.2100
486-66 Linux 27564 ISDN XFree86 11.2100
486-?? Irix 16212 ethernet PC-Xview 11.313
486-?? Irix 15406 ethernet StarNet 11.5000
486-33 Linux 4989 PPP, 14.4 XFree86 11.2100
These are from the xbench suite.
This kind of performance makes it feasible to run X-11 based
applications on a remote machine without frustrating delays, though of
course a client-server based application (like Netscape and
a Web server) will offer better performance, assuming you can run it
on your home platform.
NFS
Since the addresses are static, it is possible (and quite effective) to use
NFS to mount remote disks. I have not tried editing remote disks extensively,
but rather copy to a local directory, edit, then copy back. I have
successfully used wnewmail (biff with more detail) to check a remote
mail spool every half-hour or so. With Linux there seems to be a
problem where a file recently copied across NFS is marked "busy" and
won't execute for some time. It may be copied and renamed, though.
Mail
As someone with full-time mail on another machine, getting mail to work
is not a priority with me. I gather
that sendmail will queue mail properly and ping can be used
to open a connection occasionally. I presume POP mail will also work.
With something like sendmail running, you can have separate email addresses
for the whole family including the dog.
Connecting LANs
This is what the P-50 is designed for. Now there's no need to get rid
of obsolete home computers - just network them. Old 286's can be print servers
or act as a terminal in the garage. With something like the P-50, you can
have an Internet node in every room. Of course, additional ISP charges
may apply as you need extra ip addresses. With one machine configured
as a firewall, that shouldn't be a problem.
Overall Impressions
For editing, reading mail, reading Usenet (via Telnet), etc., it's no
faster than a 14.4 modem, because you are limited in how fast you can
read and type. However, it's much more reliable than an analog modem,
and the dial-on-demand feature makes the actual connect time much more
productive - it's simple to do something, get a coffee, do some more,
have a meal, edit some more, etc. without feeling guilty about tying up
a modem line for 5 hours (or having line noise drop your connection).
For Web browsing, it's much faster - about 10x faster than
14.4. The P-50 initially uses one B line (64kbps), then opens the second one
as demand kicks in, for a total throughput of 128kbps. Viewing pages
with 60k inline images become tolerable.
See also
Other Technologies
See cable TV and Satellite TV for other up-and-coming
ways of getting online faster. For telecommuting, though, if the workplace provides the
dialin service, the overall performance will probably be much better from an ISDN link, as the packets
go direct, rather than via Toronto or San Francisco, fighting with people getting the latest Netscape
or hot GIF.
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