Network Functions Virtualization Meets Network Monitoring and Forensics

By Adwait Gupte, Product Manager

Enterprises and service providers are increasingly flirting with Network Functions Virtualization (NFV) as a means to achieve greater efficiency, scalability and agility in the core and datacenter.

NFV promises a host of benefits in the way networks are created, managed and how they evolve. Compute virtualization has, of course, redefined data centers, transforming servers from computers to virtual processing nodes that can run on one or many physical servers. This separation of processing hardware from the abstract “ability to process” definition of servers allows a lot of flexibility in the way datacenters are managed and how workloads are managed, especially in multi-tenant environments.

Network Functions Virtualization (NFV) is a similar concept, applied to networking. But haven’t switches and appliances always been distributed network “processing” nodes? NFV proposes replacing the integrated, purpose built software/hardware boxes, such as routers and switches, with commodity processing platforms and software that performs the actual network function. Thus, rather than having a box with its own network OS, processing power, memory and network ports which together function as a router, NFV proposes having a general purpose hardware with processing power, memory and ports that run software that transforms it into a router. In some cases, it’s more costly and less efficient to hand a networking job to a general purpose processor. The advantage of this virtualized router is that the software layer can be changed on the fly to turn this router into a switch or a gateway or a load balancer. This flexibility enables polymorphism within network infrastructure and promises to deliver a more nimble design that can be dynamically repurposed according to the changing needs of the network, thus future proofing the investment made in acquiring the infrastructure.

Today switching and routing functions can be virtualized, with some tradeoffs.  More sophisticated functions for security and network/application monitoring still require hardware acceleration. Tools such as NPM and APM and security systems such as IPS, which operate on real time data, have arrived in a virtual form factor for some use cases. Technologically speaking, this seems to be the logical evolution that follows the virtualization of much of data center infrastructure. While there remains debate as to whether the tool vendors embrace or attempt to stymie this evolution, the more critical question is: What elements require optimized processing and hardware acceleration?

From the customer’s viewpoint, virtualization reduces the CAPEX allocated to such tools and systems. As virtualized tools become available, it might become easier for customers to scale their tool deployments to match their growing networks. The hope of scaling out, without needing to buy additional costly hardware based appliances, is an obvious attraction. They can instead just increase the compute power of their existing infrastructure and possibly buy more instances of the virtualized probes, as necessary. In a multi-tenant situation, these probes may even be dynamically shared as the traffic load of individual tenants varies. But what if those tools and probes cannot function without hardware acceleration? What if running them on general purpose compute proves more expensive than running them on optimized systems?

There’s no reason to adopt virtual tools and systems that can’t get the job done or that increase costs.

Further, while routing/switching are very well understood functions that even nascent players can virtualize, there is a significant operational cost to any such changeover. Advanced monitoring features are much more complicated and sophisticated. In contrast to infrastructure elements, tools and security systems require a greater development investment and more often require highly integrated hardware to function efficiently. 

I think the driving force behind this transformation will have to come from the customers, especially large ones, who have the economic wherewithal to force the vendors to toe the line towards virtualization. An example of such a shift is AT&T’s Domain 2.0 project. As John Donovan put it, “No army can hold back an economic principle whose time has come.”

As the large customers build pressure on the vendors to move towards virtualization, I think we will start seeing some movement towards NFV within advanced products of the networking space. One element of this change is already occurring in forensics or “historical” (as opposed to real time) network analysis. Historical analysis functions, such as IDS or Network Forensics, can be virtualized to a great degree, but these systems, today, tend to be monolithic devices. These devices combine capture, storage and analysis. As has been shown repeatedly in the past, there’s certainly value to specialization; especially when line-rate performance is required. Capturing network data, storing it efficiently for retrieval, and building smart analytics are diverse functions that have been coupled in the past.

Today, just as we consider decoupling network functions from underlying hardware, we should also look at the benefits of decoupling network data from analysis software and hardware appliances. After all, these systems are hardware, software, and data. Ultimately, NFV provides an opportunity for the analytics tools and security systems to offload the data capture and storage duties to other elements, enabling hardware optimization (if required) and freeing the data to be used by a variety of systems. A move towards NFV by the analytics vendors would bring with it all the advantages of scalability and cost-effectiveness that NFV promises in other networking domains—but  analytics vendors need to decouple data processing as much they need to virtualize functionality.