Newsgroups: bit.listserv.big-lan
Date:         Fri, 22 Jan 1993 15:29:20 EST
From:         BIG-REQ@SUVM.BITNET
Subject:      BIG-LAN Digest, Volume 5, Number 3, Friday, January 22, 1993

BIG-LAN DIGEST           Friday, 22 January 1993        Volume 5 : Issue 3

Today's Topics:

                         Token Ring media filters
                          ANSI EIA /TIA 568, 569
                           Routers as backbones
                                READ THIS!
                               FDDI cabling

Moderated by John Wobus, Syracuse University

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

Date:    Sun, 17 Jan 93 16:23 CST
From:    "Don M. Wee/Loyola Univ Chicago"            <$ACSDMW@LUCCPUA.BITNET>
Subject:      Token Ring media filters


> BIG-LAN DIGEST           Friday, 15 January 1993        Volume 5 : Issue 2
> Date:         Wed, 13 Jan 93 18:04:55 CST
> From:         Don Lewis <LEWIS@UMSLVMA>
> Subject:      Token Ring media filters
> Does anyone have any recommendations for TR media filters that can
> be used at 16M?  We are using IBM 4/16 TR cards in PS/2s. We would like
> to configure a segment of approx. 35 machines at 16M. Each machine
> is wired back to a Cabletron HUB via cat 5 UTP.
> Any suggestions will be appreciated.
>
> Don Lewis
> UM-St. Louis
Check with Cabletron.  They told us to use StarTek filters with their
hubs and IBM TR cards and they've been fine (after an abortive attempt
to make CABLETRON filters work.....).
- -----------------------------------------------------------------------
Don M. Wee     Loyola University Chicago
Internet: $acsdmw@luccpua.it.luc.edu   (147.126.100.1)
Bitnet:  $acsdmw@luccpua    Compuserve: 76314,3315   Fax: 312/508-6050

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

Date: Tue, 19 Jan 1993 0:02:11 GMT
From: Kevin Brown <Kevin_Brown@netcomm.ie>
Subject:      ANSI EIA /TIA 568, 569

  ANSI EIA /TIA 568, 569
Hi,

Where can I get the full spec of the above wiring standards. Also, any
comments on it's importance as a wiring standard. Have vendors started
relating their products to this standard yet?

regards,

Kevin

> Kevin Brown                        N | Network Integration and Training
> NetComm                            e | Fax:353-1-323718
> Glenlion Cliffs, The Baily         t | Voice:353-1-323718
> Howth, County Dublin               C | email:Kevin_Brown@netcomm.ie
> Ireland                            o | ________________________
>                                    m | :-)
>                                    m |

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

Date: Wed, 20 Jan 93 12:04:56 CST
From: exudnw@exu.ericsson.se (Dave Williams)
Subject:      Routers as backbones

This may be in some FAQ somewhere, but I can't find it.

I'd like to hear from any large sites that have routers configured as
backbones.  There's lots of marketing hype from the router companies
on why you "need" to do this, but very little in the way of hard info
on configuration, performance and pitfalls.

Our current configuration consists of about 400 SPARC clients fed by 13 Sun
4/490 servers. Each server has multiple NC400 Network Co-processors (one per
client network), 2 IPI controllers and 6-8 IPI disks (some Saber's, some
 Elites)
 .

We are currently setup in a straight hierarchical topology that looks something
like this:

                   server backbone (ethernet)
     +-----------------------+----------------------+-----> to existing router
     |                       |                      |      (3270, x.25, etc.)
     |                       |                      |
 +-------+               +-------+              +-------+
 | 490   |               |  490  |              |  490  |
 |  1    |               |   2   |              |   n   |
 +-+-+-+-+               +-+-+-+-+              +-+-+-+-+
   | | |  NC400 I/F's      | | |                  | | |

  client                   client                 client
  networks                 networks               networks

We typically put a maximum of 25 diskless w/s on each client network and get
about 60 clients per server.  We run NIS, DNS, automounter, etc. and the whole
thing works pretty well. We are currenly in the process of adding about 200
disks to make about half of our client population dataless, the remainder is
Sun SLC's :~(

We started questioning this layout when we noticed our "server backbone" was
hitting high % of possible lan bandwidth at peak hours of the day. We already
had common data replicated on multiple servers but it's too big to copy to
all of them. We thought about this for a bit and came up with the following
possible solutions:

1) Put a large router (Cisco AGS+, Alantec, Wellfleet, etc.) in place of the
   server backbone. These typically have near-gigabit backplanes and have *got*
   to be faster than our current Ethernet 10 MB/sec "governor".

2) Connect the server's client networks to both the clients and the router
   and turn off routing in the servers. We did some informal tests and found
   that a single client could cause 10% server CPU load just routing a single
   "find" command. I've always heard that Suns made poor routers, but could
   never find any hard data on the subject.

3) Use the router as an FDDI connection to a single server containing all
   replicated filesystems. We thought this could be a SS10/41 with multiple
   fast SCSI disks. This would free up all the space currently taken up by
   replicated data spread over all the servers while providing for faster
   access and better configuration control.

   One question that looms is whether the replicated (read mostly) data server
   should use multiple ethernet I/F's, one to each client network (using more
   than one server) or use FDDI straight into the router.  We don't have a lot
   of FDDI experience to guide us.

   Is the answer the same for database (read-write, non-NFS) servers as it is
 fo
 r
   "read mostly" (NFS) nodes?  Which is better (for NFS and/or socket DB
 access)
 ,
   multiple ethernet segments in a "matrix" topology spread over each client
   network or single FDDI interfaces from each server into the router?

We would end up with something like this:

                         "old" server backbone
           (Left intact for sanity and backup if router ever blows)
      +--------------------------+-------------------------+-------------+
      |                          |                         |             |
      |                          |                         |             |
   +-------+                  +-------+                 +-------+        |
   | 490   |                  |  490  |                 |  490  |        |
   |  1    |                  |   2   |                 |   n   |        |
   +-+-+-+-+                  +-+-+-+-+                 +-+-+-+-+        |
     | | |   NC400 I/F's        | | |                     | | |          |
    client                     client                    client          |
    networks                   networks                  networks        |
     | | |                      | | |                     | | |          |
 +---+-+-+----------------------+-+-+---------------------+-+-+----+     |
 |    enet                       enet                      enet    |     |
 |                                                             enet+-----+
 |                         router "backbone"                       |
 |                                                      FDDI/CDDI  |
 +-----------------------------+----------------------------++-----+
                               |                            ||
                           X.25,3270                  +-----++----+
                              etc.                    | replicated|
                                                      |   data    |
                                                      | server(s) |
                                                      |           |
                                                      +-----------+

Are we on the trail of something good here or have we all been locked up in
the hacketorium too long?

Specifically:

1) Is turning off routing on the servers a *good* thing?

2) What will break?

3) What are we overlooking?

4) Are there any other large sites doing this kind of stuff?

5) Is FDDI better than multiple ethernet segments for our data server(s)?
   How about for database server(s)?

Any comments/suggestions appreciated.

= exudnw@exu.ericsson.se       (214)907-7928                            =
= David Williams              "You can't win, you can't break even,     =
= Ericsson Network Systems     and you can't quit"                      =
= Richardson, TX 75081                                  my opinions...  =

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

Date:         22 Jan 93 01:00:34 CST
From: "Mike Bitz"  <BITZM@columbia.dsu.edu>
Subject:      READ THIS!

    Hello.  I am writing to inform you about a hot new discussion
list.  So hot that we have 90+ members after only 1 week of operation.
    PCBuild is a listserv devoted to the upgrading/construction/
maintaining of Windows, OS/2, and DOS based computers.
    We strongly urge you to join this list, as we are constantly
looking for more members.  Without members, none of us can either
share knowledge or learn new tips and tricks.
    To become a member of this listserv, just send a message to:
        LISTSERV@LIST.DSU.EDU
    The first (and only) line in the message must read:
        SUB PCBUILD Your Name

    Remember, once you are a member, you need not respond to every
single posting.  But just think of the knowledge you will gain as one.
Thanks for your time.
Mike,
Co Administrator of PCBuild.

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

Date: Fri, 22 Jan 93 16:58:16 MET
From: wojsyl@appli.mimuw.edu.pl (Wojtek Sylwestrzak)
Subject:      FDDI cabling

We are in process of designing the first FDDI installation in Poland.
As noone here seems to have any experience (quite obvious), we are almost
completely on our own. I think our questions might be most trivial
to people who have implemented the network.

Our network is to connect several buildings (concentrators + 'to the desk'
option) which are in about a mile distance from each other.
At first we thought of putting 24 fibres, half of them multimode but recently
we are more into using monomode fibres alone. Are there any disadvantages
of this solution ? Prise perhaps ? What are the differences in cost of mono-
and multi-mode equipment ? We thought that monomode is more expandable
and more future-proof...
The main use of the network is to connect local and remote graphic workstations
to emerging supercomputing centre.
Also what are the (dis)advantages of the dual ring topology as oposed to
tree-like topology (with concentrators in nodes). Which is cheaper,
faster, more reliable ?
What is the difference between dual and single attached devices (in cost,
performance ?)

thank you,
Wojtek Sylwestrzak
- --

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End of BIG-LAN Digest
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