Tag Archives: OSI model

Road to 100Gb/sec…Innovation Required! (Part 1 of 3)

Transport Layer Innovation: RDMA

During my undergraduate days at UC Berkeley in the 1980’s, I remember climbing through the attic of Cory Hall running 10Mbit/sec coaxial cables to professors’ offices. Man, that 10base2 coax was fast!! Here we are in 2014 right on the verge of 100Gbit/sec networks. Four orders of magnitude increase in bandwidth is no small engineering feat, and achieving 100Gb/s network communications requires innovation at every level of the seven layer OSI model.

To tell you the truth, I never really understood the top three layers of this OSI model: I prefer the TCP/IP model which collapses all of them into a single “Application” layer which makes more sense. Unfortunately, it also collapses the Link layer and the Physical layer and I actually don’t think this makes sense to combine these two.  I like to build my own ‘hybrid’ model that collapses the top three layers into an Application layer but allows you to consider the Link and Physical layers separately.

Kevin D Blog 081814 Fig1

It turns out that a tremendous amount of innovation is required in these bottom four layers to achieve effective 100Gb/s communications networks. The application layer needs to change as well to fully take advantage of 100Gb/s networks.   For now we’ll focus on the bottom four layers. Continue reading