Network Virtualization: Its Benefits and Challenges

By Chris Bastian, Senior Vice President/CTO, SCTE/ISBE

Network Function Virtualization (NFV) is a hot topic this year. Recent conferences, both inside and outside of cable, have focused significant panel time toward the topic, and NFV abstracts from many industry sources have been submitted for this year’s SCTE/ISBE Cable-Tec Expo.

The traditional architecture for a network node was that it was a self-contained device that had software and hardware components and well-defined interfaces over which it communicated with other network nodes. Cable network infrastructure elements such as routers and CMTSes and customer premises equipment such as set-top boxes and cable modems fit this description. In the past few years, the trend has been to virtualize the network node, often leaving a hardware shell running with simplified software in its traditional network location, while pulling the higher-level, and more costly, functions back to a location deeper in the network, usually at a data center. All of the aforementioned equipment—routers, CMTSes, set-top boxes, and cable modems—are currently candidates for this virtualization.

The benefits to network virtualization are significant:
1) Innovative new services can be released more quickly due to focusing on developing software only at the centralized data centers, rather than having to upgrade thousands if not millions of distributed nodes.
2) The nodes in the data center become general computing hardware, which can be shared across multiple services and which are more energy efficient.
3) The simplified yet numerous nodes closer to the customer become less expensive.
4) New, non-traditional developers will enter the marketplace to write service code.

As with any network evolution, there are challenges as well:
1) An “orchestrator” function is key to ensuring that the service functionality spread across the network stays in synch, including starting a new network service, service lifecycle management, scalability, policy management, and billing. Across service domains, each with its own orchestrator, there may also be a need for an orchestrator of orchestrators.
2) Functions that were once self-contained within a node are now split across the network, exposing new network interfaces, so interoperability testing is key.
3) Likewise, security concerns become challenging as these new interfaces are exposed and each network node must prevent unauthorized access or control, aka security is only as good as its weakest link.
4) NFV requires a high-performance network with deterministic behavior regarding throughput and latency.

The European Telecommunications Standards Institute (ETSI) has been a prominent stakeholder in driving network virtualization forward. Stateside, CableLabs has done significant work in this field. There are numerous global proofs of concept demonstrating the progress of NFV.

Each class of network node will become virtualized based on marketplace demands. Given the advantages of this architecture, it is easy to predict an accelerated schedule for NFV global implementation.

Chris Bastian is Senior Vice President/CTO, SCTE/ISBE.