Responding to current trends in the world of IT, the International Organization for Standardization (ISO) has announced a refresh of the legacy Open Systems Interconnect (OSI) model which we've all come to know and love. The original seven-layer model is to be replaced with a simplified, sleeker six-layer model which more accurately reflects service stacks seen in today's networks.
To review, the legacy OSI model featured seven layers:
• Application
• Presentation
• Session
• Transport
• Network
• Data Link
• Physical
Obviously, this was way too complex for many people in IT to comprehend. (And really, have you ever heard a decent explanation of the presentation layer's function?) The new model, OSI 2.0, features six concise layers:
• User
• Cloud
• HTTP(S)
• Virtualization
• Fabric
• Wireless
Let's look at each layer a bit closer, starting from the bottom up.
Wireless
The old physical layer has been replaced with the Wireless layer, because wired networking is so 2011. And with copper prices what they are today, who can afford to run eight strands of the stuff to every workstation or IP phone in an entire office?
Fabric
The traditional switched LAN is being replaced with an omnipresent fabric, which removes the burdens imposed by spanning tree (namely understanding how spanning tree works). The fabric layer abstracts the fabric function to allow an organization to choose from TRILL, IEEE 802.1aq, Fabric Path, or whatever other half-baked scheme comes out next week.
Virtualization
Let's face the fact: No one uses physical hardware any more, and who would want to? Virtual machines can be spun up, bounced around the fabric, and disappeared with the click of a mouse. And so long as we continue to simple extend layer across the globe, there's no limit to how far we can move them.
HTTP(S)
Given that just about everything now runs over HTTP or HTTPS, there's really no need to accommodate legacy high-layer protocols in the new model. The upper layers from the old OSI model have been condensed into the HTTP(S) layer.
Cloud
The cloud has been around for a few years, and although still no one can explain quite what it is, we can all agree that it makes us feel safer. So, ISO has included a cloud layer.
User
A direct parallel can't be drawn between this top layer and the old OSI model. Apparently, years of joking about "layer eight" problems somehow resulted in an actual layer eight (well, six) being added to the new model. Moving forward, any issues experienced on a network can be attributed to this layer by default.
