Newsgroups: bit.listserv.big-lan
Date:         Wed, 18 Nov 1992 23:01:36 EST
From:         BIG-REQ@SUVM.BITNET
Subject:      BIG-LAN Digest, Volume 4, Number 77, Wednesday, November 18, 1992

BIG-LAN DIGEST         Wednesday, 18 November 1992     Volume 4 : Issue 77

Today's Topics:

                       Re: 10BaseT wiring practices
                       Re: 10BaseT wiring practices
                         Re: Daisy chain Ethernet
                                 question
                           Question on routing
                       Re: 10BaseT wiring practices
                       Re: 10BaseT wiring practices
                         10baseT hubs as IRL's ?
                     TCP/IP Name Servers for Big LANs
               who is using both single & multi mode fiber

Moderated by John Wobus, Syracuse University

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----------------------------------------------------------------------

Date: 13 Nov 92 15:45:51 U
From: "Dave Clark" <dave_clark@pdxml2.mentorg.com>
Subject:      Re: 10BaseT wiring practices

        Reply to:   RE>10BaseT wiring practices

Subject:      RE: 10BaseT wiring practices

> Since 10BaseT requires 2 pair and since a typical level 4 or level 5 cable
> contains 4 pair, is it legal or acceptable to run 2 10BaseT applications in
> the same 4 pair cable?  What about 1 10BaseT and 1 or 2 serial applications
> such as 9600 baud serial printing?  How many pairs does it take to run CDDI?
> If the answer is 2, then what are the answers to the first two questions if
> we're running CDDI instead of 10BaseT?

We looked into this when we installed our cable plant at our new facility.
Here's the scoop: you can run any number of balanced signals (differential
drivers) inside the same bundle of twisted pair wire. You only get in trouble
if you run balanced (10baseT, CDDI, Localtalk/PhoneNET) and unbalanced (RS232)
in the same wire bundle.

- -Dave Clark -- Sr. Network Engineer -- Mentor Graphics Corp.

- -------------------------------------------------------

End of BIG-LAN Digest
*********************

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Date: Fri, 13 Nov 92 21:07:35 EST
From: dan@foghorn.pass.wayne.edu (Daniel Cwiertniewicz)
Subject:      Re: 10BaseT wiring practices

Mike Rackley <rackley@CC.MsState.Edu> said:
>..is it legal or acceptable to run 2 10BaseT applications in
>the same 4 pair cable?

I ran into that same question a while back.  Not being one to always
believe the documentation I tried to run various other protocols in
the same sheath with 10BaseT.  No luck.  The signal is too strong
and the interaction with protocols like AppleTalk makes both unusable.
The only thing we have been able to run in the same sheath is
AppleTalk and 3270 traffic.

-------------------------------------------------------

Date: 14 Nov 92 04:27 GMT
From: KEE@AppleLink.Apple.COM (Radiant Enterprises, K Nethery,PAS)
Subject:      Re: Daisy chain Ethernet

>Have anyone tried using IBM type 1 cable in Local talk network for Macintosh.
>I tried this cable using Farallon star controller and the results are good.
>I want to ask if there any specifications for the cable used for Local talk
>networks?

I have seen LocalTalk run through left over coax, through braided speaker wire,
you name it. Distances were reduced but it worked.

>Also I want to know if I can run 10-Base-T in Daisy chain configuration for
>Macintosh networks?

Can you use 10-Base-T wiring for LocalTalk, yes.
Can you use 10-Base-T wiring and daisy chain ethernet nodes together with it,
there are no products that do this that I know of.

Kee@applelink.apple.com

-------------------------------------------------------

Date: Sat, 14 Nov 1992 22:27 PDT
From: Kuang-Yang Huang <KHUANG@SCU.BITNET>
Subject:      question

Hi,

    I am a new user.  I saw a lot of mail which mentioned about CompuServe.
Is there anyone tell me what it is, what's that for?  Thanks a lot.

Sincerely yours,
Kuang-Yang Huang
khaung@scuacc.scu.edu

-------------------------------------------------------

Date: Sun, 15 Nov 92 22:26:28 -0500
From: messingr@Kodak.COM (Rich Messinger x24361 B83, Rm 1146, RL, 02203)
Reply-To: messingr@Kodak.COM
Subject:      Question on routing


Netlanders,
        I have a question about routing that I am seeing on my
        extended LAN here at Kodak.
        I have several subnets that are seem to be running properly using
        in.routed and proxyarp to connect to our network here.
        The subnets are each using a one's broadcast on the inside but the
        network they are connected to is doing a zero's broadcast. (I know
        that one's may be better than zeros but the change is not possible
        at this time.)

        I am seeing arp packets coming from the routers for these
        subnets in response to a zero's broadcast as if they are
        thinking that the zeros address is a node's address that they
        need to resolve.  Is this "normal" behavior or is it possible
        that we have something misconfigured on these routers (These are
        SUN's running 4.1.x)?

        Would it be better to run gated instead and if so, do I still need
        proxyarp with gated for the pings to work?

        Any help is appreciated.

Rich Messinger
Eastman Kodak

-------------------------------------------------------

Date: 16 Nov 92 07:16:45 U
From: "Dave Clark" <dave_clark@igppqm.ucsd.edu>
Subject:      Re: 10BaseT wiring practices

        Reply to:   RE>BIG-LAN Digest, Volume 4, N
Mike Rackley <rackley@CC.MsState.Edu> writes:
>Since 10BaseT requires 2 pair and since a typical level 4 or level 5 cable
>contains 4 pair, is it legal or acceptable to run 2 10BaseT applications in
>the same 4 pair cable?  What about 1 10BaseT and 1 or 2 serial applications
>such as 9600 baud serial printing?  How many pairs does it take to run CDDI?
>If the answer is 2, then what are the answers to the first two questions if
>we're running CDDI instead of 10BaseT?
While the electrical specs of cabling are somewhat blackbox to me, I do know
that at least one cabling system, the AMP ACO system, integrates two 10bT, two
CDDI, one 10bT and one serial circuit on a single 4-pair UTP bundle.  I have
spec'd 8 UTP pairs and 4 MM fibers to each of 150 desktops for a new
retrofitted network in my department at UCSD and if CDDI (requires 2 pairs)
catches on my level 5 should handle it.

Dave Clark
IGPP Network Operations
University of California San Diego
La Jolla, CA 92093-0225
(619) 534 1753
internet: dclark@ucsd.edu

-------------------------------------------------------

Date: Mon, 16 Nov 1992 09:08 CST
From: Larry Owen <OWEN@DUCVAX.AUBURN.EDU>
Subject:      Re: 10BaseT wiring practices

Mike Rackley <rackley@CC.MsState.Edu> asks:

>Since 10BaseT requires 2 pair and since a typical level 4 or level 5 cable
>contains 4 pair, is it legal or acceptable to run 2 10BaseT applications in
>the same 4 pair cable?  What about 1 10BaseT and 1 or 2 serial applications
>such as 9600 baud serial printing?  How many pairs does it take to run CDDI?
>If the answer is 2, then what are the answers to the first two questions if
>we're running CDDI instead of 10BaseT?

I don' know nothin' 'bout no steenkin' CDDI, but 2 10BaseT connections
in the same cable poses no problem; we do it all the time.  We also do
pretty much all combinations of serial, 3270 (w/coax baluns), 5250
(w/twinax baluns), token ring, PhoneNet, and 10BaseT over the same cables.
About the only problems we see from this are due to poor connections in
the splitters we use, normally caused by someone repeatedly slamming a
chair or desk drawer into them.

Since a serial connection is going to take a minimum of 3 wires (tx, rcv,
and ground), you're only going to be able to run *1* serial application
with a 10BaseT connection (and then only if you don't need much in the
way of control signals -- we've got some printshare devices (grrr!)
around that we've not been able to operate with less than 5 wires, so
it's 10BaseT *or* a serial, not both, with those).

Larry Owen                          email:  owen@noc.auburn.edu    or
Campus Network Administrator                owen@ducvax.auburn.edu
Auburn University                   phone:  (205) 844-4110

-------------------------------------------------------

Date: Wed, 18 Nov 1992 11:24:45 -0600
From: tcowin@trivia.coginst.uwf.edu
Subject:      10baseT hubs as IRL's ?

My question is pretty basic. We are about to put a couple Asante
10baseT hubs on our thinnet backbone, and I am concerned about
how they look (as devices) on the backbone. Are they counted as
IRL's even if they are merely T'd in via BNC connector? Or do
they merely count as IRL's from the perspective of a device hanging
off of the hub itself?
Do they actually re-time and re-transmit packets recv'd on the backbone
back onto the backbone? What are the implications for daisy-chaining
these devices? I seem to recall some discussion of when one could
and couldn't daisy-chain these.

Many Thanks, Tom Cowin

- --
Thomas B. Cowin                                      (904) 474-2507 (Office)
Institute for Human & Machine Cognition      (904) 474-3068 (Institute)
Division of Computer Science                         (904) 474-3023 (Fax)
The University of West Florida               tcowin@ai.uwf.edu (internet)
11000 University Parkway                     tcowin@uwf.bitnet (bitnet)
Pensacola, FL  32514

-------------------------------------------------------

Date: Wed, 18 Nov 92 20:25:29 EST
From: Leavitt <research@oasys.dt.navy.mil>
Subject:      TCP/IP Name Servers for Big LANs


This message is relayed from a colleague without Internet access.

She works for a large government agency that is, like many others, introducing
TCP/IP protocols into an existing IBM SNA and NETBIOS LAN environment.  They
are in the process of installing IBM's TCP/IP software on MVS and VM mainframes
and will be evaluating TCP/IP software for OS/2 and DOS+Windows.  Usage of
TCP/IP is expected to grow slowly, but an eventual population of 10,000
machines is planned, mostly IBM-compatibles with pockets of Macs, Sun
SPARCstations, and DEC VAXen.

At an INTEROP tutorial on Internet Naming and Directory Services the instructor
and several attendees said that 486-based machines would be adequate for Name
Servers.  The locally supported product list includes 486-based IBM and Dell
PCs.  The first guess at a reasonable hardware/software configuration is either
   IBM PS/2 mod 95 with AIX, or
   Dell 450SE with SCO Unix 3.2.4 or AT&T Unix System V rel 4.

Her office is short on Unix expertise and is looking for the simplest way to
 get
started.  The Dell machines are less expensive and Dell will preload the Unix
and related software in the factory.

She requests advice, based on experience please, with any or all of these,
particularly in a heterogeneous environment.

Question:  If she goes with Dell, which Unix is better, SCO or AT&T?

Is there any optional software that should be ordered?  Dell comes with a
 bunch,
but IBM is less bundled.

How much memory should be ordered?  (It's administratively easier to order up
front rather than add later on.)

How big should the hard drives be?  Is there any advantage to having more than
one physical hard drive per machine?

If the answer to the basic Dell vs IBM question is "neither," what would you
recommend?

Mike Leavitt <research@oasys.dt.navy.mil>

P.S.  I know this is not exactly this list's focus, if there is a better place
to send the message, I'd appreciate any pointers.  Many thanks.

-------------------------------------------------------

Date: Wed, 18 Nov 92 22:30:06 -0500
From: "John M. Wobus" <jmwobus@mailbox.syr.edu>
Subject:      who is using both single & multi mode fiber

On Fri, 6 Nov 1992 14:49:25 -0500 George Loftus writes:
> . . .
>Five years ago, Brown installed a Northern Telecom PBX. During that
>installation several runs of single mode fiber were installed between the
>sites where satellite PBX switches were installed. This fiber is in service
>today for voice only. Subsequently, mulitmode fiber was installed in
>locations around campus where the copper voice cable plant was being
>upraded. It just made sense to install fiber while the ground was open.
>
> . . .
>
>Now to my questions.
>
>We are trying to determine whether it would be cheaper to install multimode
>fiber next to the single mode fiber  and connect all four major sites via
>multi-mode or to use single-mode to mulit-mode converters. Has anyone used
>such a conveter ? We have gotten informal pricing of approximately
>$5000-$6000 per device (with a device needed at each end). Are there
>devices that act as multiplexors which would allow me to tie several
>multi-mode buildings to the single mode runs that are connecting the major
>switching sites ?
>
>I am basing the need to convert single mode to multimode on my limited
>research which leads me to believe that there are no current data comm
>standards which use single mode fiber. My understanding is that FOIRL,
>FDDI, 10-Base-FL and ATM (at 155 Mbps) are all specified for multi-mode
>fiber.
>
>I feel compelled to install both single mode and multli mode fiber each
>time I install cable, thus far people have agreed with me but  can not tell
>me exactly why. It is purely a "hedging your bet" decision. The major
>drawback I see with single mode fiber is the cost of lighting it up. My gut
>feel is that the laser light sources will become cheaper (in discussions
>with vendors at InterOp we found that the manufacturing cost for single
>mode light sources is not much more expensive than LED's for multi-mode,
>vendors just don't think the market is there yet)  and single mode will
>become the fiber of choice. It will scale better with the plans for Gbit
>LANs. Multi-mode already has known bandwidth limitations and with cheaper
>light sources for single mode , multimode could go the way of Level 3 UTP
>(remember just 2 years ago when that was the "universal cable" to install).

I can't answer your questions on single mode but I can tell you what we
did.  We installed a lot of multimode mode and terminated it several
years ago during a telephone-system upgrade.  These days, once your
multimode is terminated, using it for Ethernet is a snap.  Having multimode
to just about every academic building is fantastic.

Since our initial install, though, we always pull "dual" cable, with
some single mode even though we use none of it at this point.  We have
been pulling more to some locations as well as to new locations (including
dorms).

My personal opinion is that money spent on electronics is likely to
give you 5-10 years of service (and often comes with a maintenance
contract) whereas money spent trenching, laying conduit, and pulling
fiber will last a lot longer.  I've seen types of cable go out of style
and the same might happen to multimode OR singlemode.  It is a guess.
But permanent paths will still have a long lifetime.  Thus my own
inclination is to spend money pulling more fiber rather than spending
equal money on electronics to make existing fiber do what you want.

John Wobus
Syracuse University

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End of BIG-LAN Digest
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Comments: Gated by NETNEWS@AUVM.AMERICAN.EDU