The past two years have witnessed flurry of action and hype around Software Defined Networking. There are umpteen numbers of vendors claiming to churn out SDN solutions and products every other week. This paper provides a perspective on the technology, SDN industry, role of system integrators in this space, and how SI can adapt and evolve to facilitate the SDN adoption journey of customers.
Introduction: Traditional Network that we Know
Network by design has been a distributed computing environment. Each node in the network, be it a switch or a router, has both intelligence (control plane) and muscle (forwarding or data plane). Packet forwarding was done on a hop-by-hop basis with each node making forwarding decisions on its own. Configuration of these network devices was being done box by box. Troubleshooting was even more complex - with packet traces, hop-by-hop checks and required deep expertise in product architecture most of the time. Managing networks includes a mundane set of activities like backup, repeated configuration tasks, fulfillment of requests and keeping the lights on.
Most network products were proprietary and built with Application Specific Integrated Circuits (ASICs) that are tightly coupled to the operating system on top of it. It is fair to say that these were ‘black boxes’ with very limited openness either in software or hardware. Proprietary network management software from the respective product vendors was needed to manage this complex infrastructure. Thus, traditional network architectures were a vertically integrated stack of proprietary closed systems. More diversity in network infrastructure would mean more people with specialized skills, more management systems and more processes to orchestrate changes across the stacks.
What is the Problem with the Network?
With the advent of virtualization technologies the server compute block has become agile and provisioning in the Data Center is largely automated. However, the same is not true for network and associated services. Today application or workload provisioning in the DC is time consuming due to the network not being agile. Network provisioning might take several days to weeks in the DC. Most enterprise DC’s have significant product diversity in the network services layer – DNS, Load-balancing, WAN optimization, VPN and firewalling, to name a few. The deployment of these
services demand expert skills, change requests, maintenance windows and sometimes manual rollback of failed provisioning. Network operations have become complex with the need to maintain, manage and upgrade heterogeneous infrastructure. Availability of skilled personnel to oversee successful network operations is becoming a daunting task for DC network managers. And to top it all, the network is always blamed for performance issues or any other infra wide problems in the DC. Network operations are challenged frequently to prove otherwise.
SDN – The Change Agent
Network Virtualization techniques are not something new in the network world. VLANs, tunneling, and VPNs have been around for quite long. Talking about SDN, it intends to centralize all intelligence (control planes) in the network on a software layer allowing centralized control and abstraction of the underlying complex infrastructure. Theoretically, all network nodes would only need the muscle (forwarding or data plane) to push packets out.