http://www.teldat.com/blog/wp-content/uploads/2014/07/177402640.jpgNFV (Network Functions Virtualization) is a new network architecture that proposes to extend the virtualization technology used in the traditional IT environment to the different network elements, to create more flexible networks and services, easier to deploy and operate, for a reduced cost. While RAID and virtualization meant a revolution on the storage technology and on the computing and operating systems technologies respectively, SDN and NFV propose an equivalent transformation on the communications networks. Cloud Computing would not have been possible without the former technologies and SDN and NFV, in turn, rely on Cloud Computing technologies to deliver their promise.

SDN (Software Defined Networking) is also an emerging network architecture that centralizes the view and control of the network, separating the forwarding decisions (control plane) from the network elements that in fact forward the packets of information (data plane), moving, in this way, the intelligence to the “center” of the network from the previously remotely distributed networks elements, like switches or routers.

SDN and NFV can exist independently of each other, but they are, in fact, complementary technologies that reinforce themselves when used simultaneously.

The interest of network operators in NFV technology

NFV is being pushed and promoted mainly by network operators, in the fight with the “Over-the-Top” service providers, which use network operators’ networks as “dumb pipes” to offer value added services and applications to the end users. With NFV, network operators seek to reduce the time to market of new services generation and provisioning, lower the required investment (CAPEX) and the operating and maintenance cost (OPEX) and expedite the innovation by favoring open-source initiatives.

NFV (and SDN) can theoretically be applied to any network element, network part, or function. For instance, it could be applied to the Mobile Core Network of a mobile operator or to the load balancer gear of a data center.

In more or less degree, part of the functionality of these network elements is subject to be virtualized and offered, for a lower cost, in a central location, using traditional low-cost COTS (Commercial Off-The-Shelf) servers running open-source based software, instead of proprietary hardware and software from established vendors. Or at least this is what many network operators are chasing, promoting and starting to test or even trial in the real world.

But, how does all this apply to the enterprise branch office access router, that is the main network element or “function” that Teldat provides? Does this specific network element have any peculiarity or characteristic that could influence or condition the way it can benefit from the NFV and SDN technologies?

Does it make sense to virtualize the access router?

A rigorous analysis falls out of the scope of this post and one will find both advantages and disadvantages when virtualizing a network element such as the access router or CPE. But regardless of the amount of functionality that might be virtualized, let us first say that we see tough to create “smarter networks” by using “dumber routers”. This does not mean that NFV does not apply to the enterprise branch office access router, but that from all the potential benefits of the NFV and SDN technologies, the CAPEX reduction is probably the less interesting one, or in other words, the toughest to obtain.

Some market initiatives, like the HGI (Home Gateway Initiative), founded in 2004, promote a model that increases the functionality of the CPE by embedding on it a “Software Execution Environment”, able to locally execute several applications or functions. This is the opposite of the NFV model regarding where to put the “intelligence”. Both architectures will probably coexist in the foreseeable future, since both have advantages and drawbacks depending on the specific use case.

The “last mile”: A challenge for NFV  application

SDN benefits are rarely questioned on the datacenter and specifically on the datacenter switches. Nevertheless, the access network and in particular the “last mile” is a much more heterogeneous environment and the bandwidth, in roughly all the cases, cannot be considered “unlimited”, as you could “model” in a Terabit/s datacenter infrastructure. Clearly this has strong implications on the NFV possibilities for a CPE.

The more complex the network element or function, the more potential NFV has to introduce benefits for the network operator. But also, the more heterogeneous the network element environment, the more complicated is to provide an equivalent “homogeneous” virtualized scenario. The last mile is a quite complex element, with non-trivial requirements such as security, quality of service, redundancy and resilience, different media adaptation, etc. On the other side, the last mile is also a quite heterogeneous scenario, especially for integrated or converged network operators that offer a broad range of access technologies.

Interoperability issues

Before a widespread adoption of SDN and NFV can occur, a crucial issue must be solved: Interoperability must be guaranteed, so that network operators do not find themselves locked into a specific vendor solution. Carriers should be warned by their experience in the GPON world with the OMCI “proprietary” management, just one fraction of the complexity NFV can imply. The open-source oriented path the network operators are proposing can be very beneficial for them, but it will not solve this interoperability problem per-se and an “integrator” figure is needed. And “integrator” or “vendor” in this regard is pretty much the same thing.

Smart routers that suit any challenge

At Teldat we follow the SDN and NFV trends with interest and we think they will definitely change the networks for good. Being a vendor that focuses on the customer premises side of the communications, we have always needed to interoperate with the network and use and promote the use of standard-based communications. Our coming devices and many of the existing ones are future proof and SDN/NFV-ready. We do this by designing smarter devices that can create smarter networks. Although some network functions can be virtualized, the enterprise branch office network in the cloud-computing era is complex enough to benefit from a powerful future-proof access router.


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Eduardo Tejedor

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