Software Defined Networking Changing the Way Silicon IP Being Used.
D. Christopher Keil, VP of Business Development, ChipStart LLC
The increasing momentum around adopting software-defined networking (SDN), which communications markets are currently experiencing, is accelerating the need for more comprehensive system management at the system-on-chip (SoC) level.
SDN introduces the notion of “random” events sequencing, such as changing the flow of a routing or switching path in real time from sources external to the network device. Random event change management, in turn, introduces new architectural challenges for communications SoCs because the state operation sequences to be executed are not predictable, as is the case when fully contained within the network device.
Traditionally, changing routing or switching flows are managed completely within the “closed” network system. The silicon that supports these devices then relies architecturally on making changes using uniform, well-coordinated and predictable system sequences. The entire change is managed within the confines of the switch or router. Predictability helps streamline the way these changes are sequenced at the silicon level given that other flows are also managed through the fabric.
Maintaining system integrity as a whole and maximizing system performance (making sure there are no excess cycles to perform these changes) is just a matter of optimizing the base architecture. Packet headers, packet inspection and table management schemes all are finely tuned today based on uniformity and predictability.
But the introduction of random change requests now means support silicon must operate with less predictability. Previously finely tuned switching fabric architectures will need significant redesign, including how the sequence of tasks through IP blocks are performed (order and structure), how data paths behave given a mix of requests, and how arbitration logic prioritizes all this for resource access.
This realization accelerates the need for more robust system management at the SoC level since the impact of SDN is architectural. The notion that this kind of state management can be handled during device development itself will only further lower overall schema reuse and also complicate maintaining compatibility of solution schemes from chip to chip.
SDN implies then not only a revisit of the core communications architectures, but also the need to add significant global system management into the silicon-based architecture so non-uniform and unpredictable change requests can be sequenced. Only then will system integrity and performance be maintained once again for random event management.