The OSI network layer

Welcome to the OSI network layer! Its our job to give you a guided tour of the facilities of the network layer - what it does and where it fits in to the rest of the OSI reference model.

What its all about... How to use this document.

Before we begin, let us just advise you on the contents of this subweb - browsing is cool, but sometime its nice to know whats out there, you know? We've examined the Network layer in some detail, and picked out its main functions, that is, routing , congestion control and internetworking . So, if you're interested in that kind of stuff, just skip straight through to there now. If on the other hand you're new to all this and would like to get a feel for what the network layer is really all about, go to the General Overview . This is the recommended starting point for everyone!

No discussion of the network layer would be complete without seeing examples of its implementation in the real world - we've provided pages showing such examples, in ARPANET and the Public Telephone Network. More examples may be added at a later date!

Finally, we in the Network layer group know of the difficulties arising from over-use of TLA's (Three Letter Acronym's). Over use of such acronyms is, we feel, an offense worthy of hanging (or at least a damn good spanking), as it leads to sentences like

"a dummy terminal can connect to the public telephone network using a PAD (whose functionality is defined by the X.3 standard) : the interface between the PAD and the terminal is defined by the X.28 standard and the interface between the PAD and the public network is then defined by the X.29."
Now - to anyone who knows their salt, this is all fine, but to the vast majority of us (particularly those humans amongst us) this kind of talk can lead to Some Confusion. In an effort to straighten out this problem, we provide a dictionary page of well-used (and well-worn) acronyms - The TLA page . So - if in doubt about anything, have a look at this page, and hopefully it'll set you straight. So there you go! have a nice browse!