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Common Router for Multiple Network File System Servers

IP.com Disclosure Number: IPCOM000115423D
Original Publication Date: 1995-May-01
Included in the Prior Art Database: 2005-Mar-30
Document File: 4 page(s) / 167K

Publishing Venue

IBM

Related People

Lee, PK: AUTHOR [+2]

Abstract

Disclosed is a method for presenting multiple similar or dissimilar Network File System* (NFS) servers as if they were a single entity on a network. Such an invention is useful in systems where different NFS server implementations exist to support different data management schemes.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 30% of the total text.

Common Router for Multiple Network File System Servers

      Disclosed is a method for presenting multiple similar or
dissimilar Network File System* (NFS) servers as if they were a
single entity on a network.  Such an invention is useful in systems
where different NFS server implementations exist to support different
data management schemes.

The essential components of the invention are illustrated in the
Figure.

NFS Server n - The boxes labeled "NFS Server 1" through "NFS
Server n" represent the NFS servers.  As illustrated, this invention
will support multiple NFS servers, limited by values described later.

NFS Router - represents the router component that embodies the
invention.
  some connection - represents the connection between the
NFS router and the NFS servers.  The nature of this connection is
nonessential to this invention, which adds greatly to its
flexibility.  For example, the router may reside either on the host
machine itself or on an outboard processor that is attached with a
high-speed connection to the NFS server address spaces on the host.
Also note that while the main problem being addressed was coexistence
of two dissimilar NFS servers, the solution can be applied to any
number of similar or dissimilar servers.
  network transport - represents the network transport that provides
the path between the NFS clients and the NFS router.  Usually, this
would be a UDP/IP connection, but the invention allows for any type
of reliable or unreliable transport.

      The embodiment of this invention is contained in a new
component called the NFS Router.  The NFS Router acts as a front end
or agent to the various NFS servers on the host system, actually
appearing to the network as if it were the NFS server itself (i.e.,
it owns the NFS and MOUNT program ports), as shown in the figure
above.  The router's responsibilities are as follows:
  1.  receive each client request that is intended for any of the NFS
       servers to which it is connected,
  2.  determine which of those servers (one or more) is the target,
  3.  route the request to the target server(s) and wait for the
reply
       (or replies),
  4.  reply to the NFS client, if necessary.
  5.  handle any NFS server outages or lost connections.

Receive each client request - During initialization, the router
establishes a connection to each NFS server for which it is an agent.
(again, for the purposes of this description, the type of connection
between the router and the NFS servers is unimportant).  Next, the
router establishes itself to the communication stack and the RPC
portmapper as the single NFS server on that host.  This implies that
all supported servers must communicate with their clients through
this router rather than directly across the network.  After
establishing itself as owning the NFS port on the host, all client
requests will be sent to the router by the communication stack.

     Determine the target - For each...