Network and Engineering 

How ConteXtream Makes Networking Fun Again Through Virtualization

Since 1999 Comcast Ventures has been helping turn great ideas into powerful businesses. In our latest Comcast Ventures Q&A Series, we turn our focus toward ConteXtream, a privately held software-defined-networking (SDN) company that enables carriers to deliver network capacity and functions in the same way cloud providers deliver applications effectively utilizing standard compute and storage. We posed six questions to Nachman Shelef, CEO, Chairman, and Co-founder.

What's the problem you were trying to solve for with founding ConteXtream?

NS: ConteXtream was founded in 2006 with a mission to virtualize carrier networks based on the insight (of Sharon Barkai, co-founder and visionary) that it is possible to implement carrier networking infrastructure functions as software running on Commercial Off-The-Shelf (COTS) servers instead of big proprietary hardware boxes. But this radical transformation required redefining the networking problem itself and then only it could leverage IT technologies to solve this redefined problem.

Key to enabling this transition to virtualized carrier networks is to separate basic connectivity between locations from the higher functions that enable carriers to provide services per subscriber flow based on the context of the particular flow. This is done by separating functions from junctions and separating locations from identities. And by adding separation of control from forwarding, we can then complete the disaggregation of networking nodes to allow network virtualization.

What's a real-world example of how ConteXtream works?

NS: ConteXtream provides a distributed flow fabric that is context (services, subscribers and network) aware. One of the most valuable uses of such a flow fabric is to create service chains out of functions dynamically per subscriber. This solution is currently deployed in production to provide value added services to over 50 million mobile data subscribers in the US. This service abstraction and isolation layer enables experimentation with test subscribers and rapid deployment of new services on the production network, without risking existing production services to subscribers.

What¹s item one on your agenda right now?

NS: Partnering with other vendors and with carriers is item one on my agenda now.  For carriers, to get the most benefit from this transition, vendors must work together to provide solutions that are conducive to innovation and adaptation. These solutions must be based on standard interfaces and disaggregated modular functions. 

In addition, these new solutions must enable leading carriers to "program the network" by adding their own functions to the solution in order to adapt it to their particular needs. This goes beyond enabling configuration of network functions and beyond automating configuration. Just like big enterprises write their own software as well as purchasing software from vendors, so will carriers be able to write their own network functions in addition to purchasing functions from vendors.

What advice would you give to startups / entrepreneurs?

NS: Networking is fun again! Networking in general and carrier networking in particular were, in the past, domains of much innovation and therefore a great area for entrepreneurs to focus on. This has not been the case over the past decade, but with the transition to Software-Defined-Networking (SDN) and Network Function Virtualization (NFV)… networking is again a great area for entrepreneurs to focus on.

What differentiates you from the competition?

NS: Our approach to Carrier Network Virtualization includes the common capabilities needed by many Virtual Network Functions (VNFs), to be elastic, distributed and subscriber aware, in the virtualization infrastructure itself. This approach enables carriers to get more of the potential benefits of network virtualization.

The simplistic approach to Carrier Network Virtualization attempts to change as little as possible in transitioning to virtualization. In this approach, big multi-function proprietary networking boxes (sometimes referred to as god-boxes) are replaced by big multi-function VNFs in software. The cables that connected the big boxes are replaced b.y a simple virtual network that provides virtual cables. In this "fat-VNF & simple-Infrastructure" approach each VNF needs to itself provide for scaling through Virtual Machine (VM) elasticity, for distribution across locations, for sharing states between VMs, for load balancing, for service chaining of sub-functions and for subscriber awareness as needed.

A more advanced approach is to rely on the virtual network infrastructure to provide these capabilities (scaling through elasticity, distribution, sharing state, load balancing, service chaining and subscriber awareness) to all VNFs as needed. This approach enables simpler VNFs, faster development, more innovation, reuse of sub-functions for many VNFs, less vendor lock-in, best of breed for every function.

Putting these common capabilities in the virtualization infrastructure creates a "VNF isolation and abstraction layer" that enables fast time to market with new functions that are not connected directly inline. Implementing and thoroughly testing these inline common capabilities of the infrastructure once is more reliable than implementing them separately in each VNF.

In short – though we support both the "fat-VNF & simple-Infrastructure" approach and the "slim-VNF & smart-Infrastructure" approach, we highly recommend the second approach in order to get more of the potential benefits of network virtualization.

What has surprised you the most about this space?

NS: What surprised me most about this space was to see how leading carriers got together and wrote the NFV white paper in 2012 calling on the vendor community to join them in the transformation of this industry.

We have been meeting with carriers since 2007 and trying to convince them of the potential benefits of network virtualization. Before 2012 and the NFV whitepaper, it was very hard to find forward thinking CTOs that both understood the potential of virtualization and could also guide us to specific projects that could be early practical use cases. We were lucky to find 3 such technologists, one of which is Franklyn Athias at Comcast. "Thank you" to Franklyn for guiding us before network virtualization became trendy!