What now feels like a life time ago back in the dim and distant past ,OK - not so dim and distant 1980s, I was a young apprentice engineer with my training and interests firmly focused on Hardware (micro electronics more specifically). In 1987 I made the bold step towards software engineering as a choice, since it seemed, back then, that software was the way forwards to creativity and new solutions for communications. Having "converted" to software engineering by way of a degree in Computer Science at Aberystwyth University, I then continued in that vain becoming a professional software engineer. I still didn't forget the electronics that got me started, and this combined with software engineering put this to good use as a telecommunications engineer. Moving through the heady days of Nortel Passport Frame Relay Switches, Cisco AGS and MGS routers and Cabletron hubs.
Then the Internet happened.......
For the telecoms engineers out there (like me), in my humble opinion (IMHO) SDN is the networking equivalent of softswitches? The OpenFlow API is what MEGACO/SIGTRAN is to soft-switching and the so-called Orchestration layer the Stored Program Control Logic from the switch fabric and routing fabric. The media gateway is the Hardware forwarding platform (L2 switch fabric being physical of logical vSwitch, Microsoft Network Virtualisation and Virtual Subnet Identifiers), not to mention MPLS enabled VPLS and the rest of the MPLS "family".
And now in the telecoms field we're getting all excited about Network Function Virtualisation (NFV - http://www.etsi.org/technologies-clusters/technologies/nfv) . This is really about extending the Virtualisation platforms/techniques like those provided by VMWare ESX and Microsoft HyperV into the telecoms space and placing the Functional elements of the NGN network on these virtualisation platforms. As the ETSI White paper states:
"leveraging standard IT virtualization technology to consolidate many network equipment types onto industry standard, high-volume servers, switches and storage "
This allows the economies of scale that the enterprise networks are gaining through "cloud compute" to the telco space, by implementing these traditionally custom hardware based elements (such as media gateways, firewalls, SBCs, Routers, CSCFs) in standard (commodity Servers) architecture servers and a hypervisor layer, utilising the same virtualisation tools which enable flexibility of deployment of these elements in more standard environment, enabling features such as live migration of network functions under failure, multiple instances of a network function on the same hardware elements, and more interestingly (from my perspective) the ability to create multiple instances belonging to different customers (or even carriers) on the same hardware platforms.
Time to re-write the architecture rule book.