series 1I’m often asked about Software Defined Networking (SDN) and when is the best time to implement a strategy. Customers and prospects are often unsure whether to embrace SDN now, soon or hold off for now. To help clarify my perspective, I’ve written a 10-part blog series.  I’ll be posting the entire series over the next five weeks and welcome any direct questions or thoughts from you.

Background on SDN.

The primary goal of SDN is the separation of the data plane from the control plane and centralization of the control plane intelligence enabling holistic network routing decisions to be made.  The data plane is then free to pass packets in an efficient per-hop manner proscribed by the control plane using virtual overlay (or underlay) networks.  Virtual networks are not new and have existed in many forms over many years – for example MPLS, VPNs, ATM, Frame Relay, VLANs, etc.  SDN aims to decouple the overlay from specific hardware technologies and to provide pan-network overlay controllers which perform provisioning thus significantly increasing network agility.  These controllers are able to dynamically reconfigure network paths to avoid congestion, implement new services, add in-path virtual infrastructure, etc.

Network Function Virtualization (NFV) and SDN are related, though it is possible to implement either one in isolation or both together.  NFV has been evolving for some time and most enterprises have deployed some form of virtualized switches, load balancers, WAN accelerators, firewalls, etc.  The virtualization of such network functions enables rapid virtual appliance instantiation and relocation for optimal placement and/or appliance distribution – e.g. pushing firewall capability out throughout the network rather than simply occurring at fixed physical (or virtual) network locations.

Later this week in part 2 of the series, I’ll cover overlay SDN and underlay SDN.

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