title: Can we talk?

Internetworking NetWare File Servers
and Adding NetWare File Servers

     As the network grows, new file servers are sometimes needed. 
Adding file servers to a Novell network is relatively simple to
do.  But, there are a few configuration issues to consider when
adding a new file server.  The following discussion presumes that
the new server has been prepared and is ready to begin its
service.

     First, there is the consideration of how the file servers are
actually interconnected.  The figure below demonstrates a network
where the file servers share a "file server only" backbone:

  server 1                   server 2                  server 3
     ________________________ _________________________
 ___|___________          ___|_____________         ___|___________
| LAN A   LAN B |        | LAN A   LAN B   |       | LAN A  LAN B  |
|   1       2   |        |   1       3     |       |   1       4   |
 -----------|---          -----------|-----         -----------|---
            |                        |                         |
            |                        |                         |
          wstns                    wstns                     wstns

     The workstations (wstns) on this network are capable of only
(initially) connecting to a single file server, the one to which
they are directly cabled.  If that initial file server is down,
then the workstation is unable to communicate with any other
server.   However, this is not usually the problem it seems to be. 
If the server is down, the workstation that connects to it will be
unable to connect to a network.  But, if its server is down, it
could very well be that the workstation is not able to do its work
anyway (because the workstation's data resides on the down
server).  An upside to this arrangement is that network fault
diagnosis is easier.  Diagnosis is facilitated by the modularity
innate to this internetwork arrangement.  Generally the search for
faults can be narrowed down to a single, localized, leg of the
network.   Also, adding workstations does not involve the
"downing" of the file server backbone, which would disable active
workstation and file server connections.
     Also note that the above figure is not dependent on any
particular network topology, any topology can be used, including
different topologies for the backbone and workstation connections.  
Also, the numbers 1,2,3 and 4 represent the "internetwork"
addresses of each of the network boards (LAN A, LAN B, etc.). 

Notice:

The boards that connect the servers all share the same
internetwork address, in this case, address 1 is used.  This is
very important to remember!    Likewise, all file server "LAN"
interfaces that do not connect must use dissimilar addresses.  For
instance, if you use address 2 on one file server where that "LAN"
interface only connects to workstations, no other file server can
use address 2 (note: the above figure does represent this
particular event).


     The next figure demonstrates a network where the file servers
and workstations share a common "backbone"

              wstn                          wstn
  server 1      |            server 2         |        server 3
     ___________|___ ________ ________________|_ ______
 ___|___________    |     ___|_____________     |   ___|___________
| LAN A         |   |    | LAN A           |    |  | LAN A         |
|   1           |   |    |   1             |    |  |   1           |
 ---------------    |     -----------------     |   ---------------
                    |                           |               
                    |                         wstn              
                  wstn                                            

     The above network design facilitates workstation to file
server connection by allowing the workstations to connect to any
file server without requiring the services of a particular server
to gain entrance into the network.  In this way, the above diagram
is unlike the first diagram.  However, if users primarily need
service of a single file server, the above layout could be more
confusing because it is not strictly defined where each
workstation is supposed to connect.  To clarify, when the network
shell (NET3, NET4) is loaded it broadcasts a Get Nearest Server
message on the network to which it is connected.  The first file
server to respond becomes that workstation's "default" file
server.  This is because the all workstations and file servers are
on the same "backbone", thus giving all file servers the chance to
hear and respond to a workstation's Get Nearest Server request.

     There are several other ways to interconnect file servers. 
The preceding is meant to demonstrate two different starting
points for connecting file servers.    


By: John T. McCann 6/22/89 1:17am
Byline:  Systems Developer for Brightwork Development  and  Wizard
SysOp of Novell's Netwire forums on CompuServe