SORRY response time was so long, someday I need to do a survey of
how many sys admins per # of unix systems.
Here we have 2 for 9 servers 150 workstations
27 sgi's and 15 HP's 15 xterms and 20 diskless
clients.
ORIGINAL QUESTION was:
A polling question for the group, and will summarize.
If you had 200 sun-sparc workstations and 7 servers with no ALM boards,
and 20 phone lines available for dialin purposes, how would you put
a communication system together?
Our problem:
We have 4 extremely old "bridge" communication servers,
which we are now attaching 9600 baud modems to. Previously with
< 9600 baud modems we let the bridge with two 8 line rotaries
auto-baud auto-parity with connections to all 7 servers which where
supported by kermit. With the 9600 baud modems we have been trying to
get data-compression supported, but are running into trouble.
We have put zmodem on the sun servers and procomm-plus on the pc
side with both modems set at all sorts of baud rates and configs
and have been unable to transfer any binary files. We always get
"BAD CRC" when sending from sun to pc, ascii files have even at
times been flacky. Never have been able to do an upload.
A direct connect to a Sun server appears to down load any file
correctly with data compression.
We have a few pennys to spend to purchase whatever - and I am extremely
interested in what other have done by way of setting up serial line
support to unix systems, for pc's, mac's ...
Summary:
15 votes for Xylogics Annex III
2 votes for Magma Products
1 vote each for misc advise
We do have a temporary fix.
ANSWERS WERE:
buy a cheap ethernet based terminal server (You may want to make
sure the terminal server accepts/supports X protocol) I would STRONGLY suggest
that you do not direct-connect a modem to any server class machine. (We've
done it in the past and they are a nightmare to administer.)
The terminal server concept also buys you dual password protection
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dal@gcm.com
I would say go with an annex 3. We just got one and it seems to be a
good box.
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blymn@mulga.awadi.com.AU (Brett Lymn)
Get some annex terminal servers to handle the modems, they are robust,
run at 38400 and are very nice to maintain. We use them here for our
modem pool without problem (they also support slip and ppp)
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We use Xylogics (formerly Encore) Annex network terminal servers.
The Annex-III has full modem control and hardware flow control on the
serial ports (older models only had one set of control lines). We
attach the modems to the serial ports on the annex at a fixed baud
rate (38400) and let the modems do speed conversion. We have not had
any major problems with the Annex communicating with the Suns over
TCP/IP.
The Annex also supports [compressed] SLIP and PPP. There is a
lot of flexibility for security control.
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I'd go for a xylogics terminal server.....they don't load down your Sun(s),
they are self-contained for up to 128 ports, they operate at many speeds
for both inbound/outbound, they have SNMP, they have PPP, and you can put
hooks in for security authentication (e.g SecurID).
if you have problems with your ALM's you'll have to knock machines down,
get patches, schedule outages, etc. ...with the terminal server you can almost
do wahtever you whenever you want....
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ed@magma.COM (Ed Romascan)
Both uunet and NLnet use our MAGMA 16 Sp 16 port SBus
serial boards to connect to high speed v.32/v.42 modems.
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fabrice@pure.com
For Macintoshes, our solution is a GatorLink with AppleTalk Remote Access.
This is an incredibly simple yet powerful setup. For the Unix systems, we
are getting a second-hand Cisco terminal server. I have been very satisfied
with previous Cisco products and would recommend them for your application,
although I don't know their latest terminal server products.
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<rackow@mcs.anl.gov
I'd get an Annex terminal server. They come in several flavors,
so you can find one to match your budget AND possibly give you
some room for growth. We have been very happy with ours for
six or seven years now.
I think the new "sun" terminal server is just an annex with a
sun logo-label put on it.
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We have had many similar experiences. The problem resolves down to the following:
the terminal server / "Bridge Communication Server" (CS-2100???) is
improperly buffering the data between the modem and the Sun.
Xylogics also failed the test, BTW.
We complained to 3Com (who marketed the "Bridge" CS-2100), and to Xyplex,
all to no avail.
We replaced them with Xylogics Annex III terminal servers, and we're
quite happy now.
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bsmart@verdix.com
In the past we have used Xylogics Annex terminal servers. They have worked very
well, have a very 'Unix like' interface. We are now also using Telebit Netblazer
terminal server/routers. Not quite as Unix-like but they have very good PPP
support and we have both Async and 56K lines coming into the same box. Both
have been very reliable. We initially went with a stand alone terminal server
instead of serial ports on the server because it meant we could upgrade servers
without having to worry about disrupting our dialins ( or our internal terminal
lines) it also reduces the critical failure points as we have two terminal
servers and multiple servers. It also gives us a little extra security as we
have a periodicly changing terminal server password that a user must enter
after dialing in. then they do a telnet or rlogin to the server of their choice
where they use their account password. I will say the Annex does the access
password better than the Netblazer.
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<Gregory.A.Parmer@acenet.auburn.edu
We've just been going through similar upgrades for our system. Leaving
Kermit, E-7-1, and ALM2 board behind. It still has a few bugs, but is
working pretty well overall.
SPARCstation end
Serial Ports:
We bought 2 8-port MAGMA cards (MAGMA, San Diego, CA 92121) which
plug into Sbus slots. They also have 16-port models I believe, but
we liked the flexibility of 2 8s. Speeds up to 115.2kbaud supported.
Having 8 serial ports/server available for login eases maintenance by
keeping logins somewhat localized but loads are still distributed.
Modems:
Telebit Worldblazer modems support PEP, MNP, and the preferred
standards of v.42bis etc at speeds up to 115.2kbaud also.
(Haven't tested >38.4k over rural Alabama phone lines. Skeptical.)
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Buy one or two CoAlm boards from CoSystems for serial data interface, then
dedicate a Sun system to act as a dialback server, put the CoAlm board(s)
in this system, buy or write the appropriate dialback software (a number of
commercial packages are available, or you could write your own as we have),
and have it handle all serial off-site data.
We have about the same setup - 230 workstations, 10 main file servers, and
already have six 16-port terminal servers and a Micom port selector for access
to every office in the building. Using modems that have dialback builtin is
not acceptable, since dialback on the same phone line is not considered secure.
We are in the process of upgrading from our old dialback system to a new one
using a Sun System running dialback software, CoAlm serial boards (which run
a lot better and faster than Sun Alm boards, for less), and a modem pool of
off-the-shelf high-speed modems (v.32, v.32bis, v.42, V.42bis, MNP5, etc).
--------------------------------------------------------------------------------
If you have a CS-200 series bridge, put FCF & FCT settings to
follow:
CS-200 communication server:
FlowControlFrom = ( CTS_RTS )
FlowControlTo = ( CTS_RTS )
If they are something else, you get always CRC error with other
protocols than kermit. (Kermit compiles non-printable chars to
between 32-127).
Line isn't 8-bit wide, even you all hardware is set to 8N1.
I have two Sun's own SPC/S 8 line extension card in IPC and
dial-in and out lines go thru bridge.
PC -> Sun binary sending, still not work, because there are
bridges "escape charater" and rzszunix.tar's zmodem not compile
non-printable characters. I have hear rumours at there are
zmodem version which can do it, but I dont have see it.
Maybe escape character can eliminate, but that's is secure
option. (You can escape jammed lines to other shell, if you
first login shell don't receive any characters, deft !)
Sun -> PC work's great:
Sun -> LAN -> CS-200 -> 19.2 baseband -> my home PC.
Second point is performance.
SPC/S port has 158 k/bit limit. which means at you can connect
8 * 19.2 modem's, but every modem which runs higher rates will
eat speed for others. That's why you must check card's maximum
comminication rate before you buy it.
There are maybe other card with poor performance.
I can recommered SPC/S card. Ask manpage if you are
interesting.
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<geertj@ica.philips.nl>
There are pretty cheap 16-port Sbus boards available these days. They use
one Sbus slot, have 16 RJ45's, have hardware flow control, and seem to
work (I have one, not installed yet).
A brand I remember is 'magma'. Mechanically not the soundest, but
it is reasonable OK. I have to look up the address if need be.
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bilker@pluto.crd.ge.com
gwolsk@netcom.com
have similar problems or were interested in the answers:
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Temporary Fix was
We set baud rates on modems to 9600 we enable hardware handshaking - RTS/CTS
which we had not done previously, we turned off auto-parity and auto-baud
selection on the Bridge 100's and everything appears to be okay. The speed
has tripled and we do not appear to have transfer problems.
We will be purchasing the Xylogics Annex III next year. Primarily because
we are bringing up ppp on our unix servers and it is supported thru this
communication server.
This archive was generated by hypermail 2.1.2 : Fri Sep 28 2001 - 23:08:16 CDT