Computer science giant Alan Turing was featured in the recent movie “The Imitation Game.” Turing was especially interested in the topic of artificial intelligence, and proposed a test for determining whether a given computer was intelligent. He asked, "Are there imaginable digital computers which would do well in the imitation game?” Turing created a test in which a human evaluator would communicate by text with both a computer and another human. If the evaluator can’t reliably identify the computer then it is said to have won the game.
The point of the test is to separate the behavior of an entity (computer or human) from its implementation (flesh or circuits). Another way to look at the test is as a “black box” treatment of behavior, where you can only stimulate the entity and observe its external behavior, but you can’t see its innards.
Network Functions Virtualization (NFV) proposes to replace today’s closed appliances with software running on open servers. For NFV to be successful, it must provide operation and performance equivalent to today’s appliances. I am going to suggest a Turing Test for services built using NFV that would allow us to say whether a virtualized service acts like a service delivered using closed appliances.
Services Built with NFV Must Meet Today’s Requirements
NFV enables replacement of today’s closed network appliances (such as routers and firewalls) with software virtual network functions (VNFs) running on an open server. For example, the figure below shows a black box view of a managed router service. This view applies whether the service is built with appliances or with VNFs running on open servers.
In both the traditional and virtualized cases the black box network view is (or should be) the same: a CE router at the customer site, and a PE router at the central office or point of presence. In other words, the peers to the virtualized routers neither know nor care whether the routers shown above are appliances or software implementations.
Service providers looking at NFV have legitimate concerns about whether it can meet the requirements of today’s services, including performance, reliability and interoperability.
Fortunately it is straightforward to apply a Turing Test to network functions implemented with NFV. We can test them using existing methods and verify that the new composite of software and hardware meets the same performance, reliability and interoperability parameters as the legacy solution based on closed proprietary hardware.
Performance
Performance is the number one concern of operators looking at NFV. We at Overture have addressed this concern with our high-performance Ensemble Carrier Ethernet (ECE) VNF, which implements a virtual NID and enables high packet throughput on low-cost hardware. To verify this performance we used standard packet test equipment and a standard RFC2544 test suite to measure the throughput and latency performance of ECE. The test equipment measured the packet performance for ECE and routing VNFs just like it would for a system composed of NID and router appliances. Likewise the resulting reports are just like those for appliances. Click here to learn more about this NVF performance benchmark test.
Reliability
Reliability is another aspect of NFV that worries operators. They are accustomed to a system of network elements that are individually reliable. In contrast, NFV is based on technology derived from a cloud model where the overall system is reliable but the individual components are not. It is possible to merge the cloud and telco views of the world by using pairs of redundant elements to create a highly reliable system that provides the same levels of reliability and availability as today’s appliances. Service providers can apply standard analysis methods to predict the availability and reliability of such as system. You can click here to read more on this topic.
The Imitation Game is Just a Start
NFV helps service providers create innovative and agile services that can be delivered at a lower cost point than today’s traditional services. However, NFV must meet the performance and reliability levels that are today provided by legacy appliances.
The good news is that it is possible to use standard tools to verify the performance and operation of a virtualized network function or service. More importantly, as with Turing’s original “Imitation Game” the point of passing the test is not an ending. It is a beginning step on a journey of innovation.