RAN: Rack Area Networking

By | December 4, 2009

Ever heard of a Rack Area Network?

The term, as well as the concept, of Rack Area Networking is one I’m hearing more and more often.  As a result of this, as well as the fact that I’m convinced this is going to be one of the most interesting and important areas of Data Center computing over the next few years, I’ve decided to write a mini-series on the topic. 

This post is instalment number 1 and is intended to introduce the concept and get the ball rolling.  The whole thing is a bit of me thinking out-loud and attempting to generate some awareness and conversation around the topic, as .  So please pitch in!


Rack Area Network – the concept

For me, Rack Area Networking, or RAN for short, is an umbrella term for most of the clever networking and I/O virtualization stuff that goes on within a rack – a 42u rack. 

With it being “Rack Area”, it is a close proximity network and as a result operates over very high-speed low-latency interconnects.  

Physically, RAN technologies include a new generation of at least the following: I/O adapters, cabling, Top of Rack (ToR), and may be even End of Row (EoR), switches.  However, for reasons which will become clear, the emphasis is heavily on the clever – technologies that enable the flexible, the dynamic and the virtual aspects.

For example, the I/O Adapters driving the RAN evolution are not just faster than the legacy adapters they are replacing, they have built-in cleverness – hardware virtualization and huge flexibility! 

Some of the other technologies that define and operate within the RAN include – SR-IOV, MR-IOV, vNIC, vHBA, CNA, FCoE, Hairpin-turns, switching in the adapter, VNTag, VN-Link…. just to name a few.  In future posts we will discuss most of them.

As well as the above new hardware and technologies, the RAN also requires and includes a new generation of management software and functionality.  True value is often in the software – the glue that holds it all together and makes it all happen.

The best part being, there are early RAN technologies already out there in the wild.  And they are already delivering real-world tangible benefits.

Some technologies driving the evolution…

It’s really important to note that while technologies in the RAN are experiencing a period of accelerated evolution, it is most definitely an evolution.  The changes are happening fast, but they are not huge disruptive changes.  For the most part, they are improvements and enhancements, albeit major, on what we already know and are comfortable with.  E.g. take PCIe adapters and create multiple virtual adapters (vNIC and vHBA) in hardware….

Just a few of the currently shipping RAN technologies include –

NOTE: Let me know if I’ve missed any major RAN technologies off the list

Some of the above technologies are very much generation 1 and only a small step towards the RAN, bringing only small benefits.  Whereas others are a major step with huge benefits.  All vendors are scrambling to take the lead in this evolving area.  In later posts we’ll dig deep into most of them.

Blurring the Lines and Causing Havoc

Naturally, many of these technologies are challenging and threatening the traditional server/network edge configurations we are used to. 

Hairpin turns, switching in the adapter and avoiding edge switches are just some of the paradigm shifts that RAN technologies might force us to consider.  Such topics are the subject of intense and engaging debate.  All very interesting and some of the concepts are very cool!

In upcoming posts we’ll talk about the likes of – SR-IOV MR-IOV Hairpin-turns VirtenSys Flex-10 VEB Xsigo VNTag NextIO VNLink InfiniBand PCIe

Thanks for dropping by and feel free to throw in your penny’s worth.


I am available as an independant freelance consultant and can be reached via the Contact Me page.

If you're thinking that I might just bemaking some of this stuff up or inventing buzwords, then you need to check out my follow-on RAN and IOV related posts listed below

IOV vNICs and vHBAs

IOV and introducing hairpin turns

7 thoughts on “RAN: Rack Area Networking

  1. Pingback: Tweets that mention RAN: Rack Area Networking – Technical Deep Dive -- Topsy.com

  2. stephen2615

    Can you please reference (by way of links) some of those terms that you talked about.   A Google search on Hairpin-turns doesn't show much worth looking at.
    I don't have the time to go wandering about the web looking for stuff that may or may not be worth it.. 
    I do find the mention of infiniband a bit interesting.  I have been using it on some intense clusters for well over 5 years.  I was happy to see it mentioned in the first draft of FCoE but vendors seem to be losing interest in it.
    Good luck with this site. 

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  4. Nigel Poulton Post author

    Hi Stephen,

    Thanks for checking out the site.

    Yes there is very little on the internet using the terms “hairpin turns” or “hairpinning” in relation to networking. However, I will be writing about it later this week. Searching terms like VEB, VNTag and VN-Link might be useful.

    On the topic of IB…. this is almost certainly a technology that suffers hugely from FUD. Great technology but may never see widespread use because of competing technologies and FUD.


  5. Pingback: Rack Area Networking? But what if all you’ve got is a rack? | Standalone Sysadmin

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