Please Whitelist This Site?
I know everyone hates ads. But please understand that I am providing premium content for free that takes hundreds of hours of time to research and write. I don't want to go to a pay-only model like some sites, but when more and more people block ads, I end up working for free. And I have a family to support, just like you. :)
If you like The TCP/IP Guide, please consider the download version. It's priced very economically and you can read all of it in a convenient format without ads.
If you want to use this site for free, I'd be grateful if you could add the site to the whitelist for Adblock. To do so, just open the Adblock menu and select "Disable on tcpipguide.com". Or go to the Tools menu and select "Adblock Plus Preferences...". Then click "Add Filter..." at the bottom, and add this string: "@@||tcpipguide.com^$document". Then just click OK.
Thanks for your understanding!
Sincerely, Charles Kozierok
Author and Publisher, The TCP/IP Guide
NOTE: Using software to mass-download the site degrades the server and is prohibited.
If you want to read The TCP/IP Guide offline, please consider licensing it. Thank you.
NFS Architecture and Components
(Page 1 of 2)
Considered from the perspective of
the TCP/IP protocol suite as a whole, the Network File System (NFS)
is a single protocol that resides at the application layer of the TCP/IP
(DOD) model. This TCP/IP layer encompasses
the session, presentation and application layers of the OSI
Reference Model. As I have said before
in this Guide, I don't see much value in trying to differentiate between
layers 5 through 7 most of the time. In some cases, however, these layers
can be helpful in understanding the architecture of a protocol, and
that's the case with NFS.
NFS Architecture and Main Components
The operation of NFS is defined in
the form of three main components that can be viewed as logically residing
at each of the three OSI model layers corresponding to the TCP/IP application
layer (see Figure 253).
These components are:
- Remote Procedure Call (RPC): RPC is a
layer service used to implement client/server
internetworking functionality. It extends the notion of a program calling
a local procedure on a particular host computer, to the calling of a
procedure on a remote device across a network.
- External Data Representation (XDR): XDR
is a descriptive language that allows data types to be defined in a
consistent manner. XDR conceptually resides at the presentation
layer; its universal representations allow
data to be exchanged using NFS between computers that may use very different
internal methods of storing data.
- NFS Procedures and Operations: The actual
functionality of NFS is implemented in the form of procedures and operations
that conceptually function at layer
seven of the OSI model. These procedures
specify particular tasks to be carried out on files over the network,
using XDR to represent data and RPC to carry the commands across an
These three key subprotocols
if you will, comprise the bulk of the NFS protocol. Each is described
in more detail in a separate topic of this section on NFS.
Figure 253: NFS Architectural Components
NFS resides architecturally at the TCP/IP application layer. Even though in the TCP/IP model no clear distinction is made generally between the functions of layers five through seven of the OSI Reference Model, NFSs three subprotocols correspond well to those three layers as shown.
Key Concept: NFS resides architecturally at the application layer of the TCP/IP model. Its functions are implemented primarily through three distinct functional components that implement the functions of layers five through seven of the OSI reference model: the Remote Procedure Call (RPC), which provide session-layer services; the External Data Representation (XDR) standard, which manages data representation and conversion, and NFS procedures and operations, which allow application-layer tasks to be performed using the other two components.
|If you find The TCP/IP Guide useful, please consider making a small Paypal donation to help the site, using one of the buttons below. You can also donate a custom amount using the far right button (not less than $1 please, or PayPal gets most/all of your money!) In lieu of a larger donation, you may wish to consider purchasing a download license of The TCP/IP Guide. Thanks for your support!|
Table Of Contents - Contact Us
The TCP/IP Guide (http://www.TCPIPGuide.com)
Version 3.0 - Version Date: September 20, 2005
© Copyright 2001-2005 Charles M. Kozierok. All Rights Reserved.
Not responsible for any loss resulting from the use of this site.