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Why network function virtualisation matters

The corporate network is coming under strain as employees bring their own devices into the workplace and businesses make more use of cloud services

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Networks that were engineered for a known IT environment, with a fixed number of endpoint devices and a suite of corporate applications, no longer fit with business’ expectations for greater flexibility and the move to digitisation.

To support greater network flexibility, major communications service providers are developing network function virtualisation (NFV) services. In July, network providers AT&T and Verizon released on-demand NFV services.

According to analyst IDC, the network is critical to digital success. In the IDC whitepaper Digital transformation obstacles and how to overcome them, sponsored by Verizon, the analyst predicted that digital transformation would drive connectivity levels up 50% across all industrial sectors in 2016 alone.

“Encouragingly, our study points to broad plans to invest in latest-generation network upgrades, such as software-defined networking (SDN) and network function virtualisation (NFV), the whitepaper said.

IDC’s John Jackson wrote: “Digital leadership requires advanced software-driven orchestration of data and the policies and SLAs that surround it with optimised routing across networks. Multiple cloud platforms must integrate with on-premise and co-location services to create a unified enterprise environment. 

“Network security and compute resources must be provisioned in near real time through self-service portals, and resources should reallocate dynamically or even automatically based on predefined business rules. All of this must happen with performance and security that inspire confidence amid extraordinarily new levels of complexity.”

Changing IT landscape

Network operators are looking to adapt to a changing IT landscape. Peter Konings, director of products at Verizon, said: “Ten years ago, an organisation had all its employees working in one of its offices.

“Staff consumed enterprise applications hosted in the corporate datacentre, and used company-provided devices, protected by a corporate firewall. The reality today is that employees need flexibility and work across multiple devices and some of the applications they use are from a public cloud.”

And the corporate IT landscape keeps changing. For instance, Konings said a business unit may decide it requires a new application and will buy it on the corporate credit card without informing the IT department.

“Many of the ways networks have been designed have remained static,” he said. “A hub-and-spoke approach to networking is quite robust, but this approach is static and such networks are no longer able to truly support continuous changes in agile business.”

With network function virtualisation, services that ran on hardware in the datacentre, such as routing, WAN optimisation and firewalls, can now be delivered in software.

Verizon’s Virtualized Network Services offers what the company describes as network-as-a-service through an open platform. The Verizon service supports the likes of Cisco, Juniper and Palo Alto.

Read more about NFV

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Moving applications into the cloud greatly changes the way workloads are routed, said Konings. A few years ago, cloud providers began offering secure interconnectivity between on-premise datacentres and cloud-based services. But this has its limitations because not every application has the same network requirements, he added.

NFV offers IT departments a way to optimise the network dynamically based on the requirements of the applications being run on top of it.

“We give the customer some simple choices – either a traditional routed network or a software-defined network,” said Konings.

According to Konings, the Verizon SDN network is designed to ensure an application always takes the most appropriate route. The service is delivered either as an on-premise appliance or as a cloud service. The appliance is effectively an Intel-based blade server offering simple routing, on which additional network services can be run.

Verizon is also launching a virtual cloud platform, which Konings said would be rolled out in 30 global markets by the end of the year.

In terms of licensing, Verizon charges a single monthly fee, he said. The actual cost varies depending on the services run, which can be based on consumed bandwidth or on the number of connections.

Managing NFV

According to analyst Gartner, as elements become virtualised, network providers are expected to add real-time monitoring and automation as well as on-demand performance monitoring capabilities. As more and more network elements are virtualised, monitoring of capacity across physical and virtualised networks will become critical, Gartner analyst Amresh Nandan wrote in the report SDN/NFV requires a new IT architecture in CSPs.

For example, Nandan said fault management systems have been used mainly for service assurance. Going forward, he suggested these systems could also be used as feedback for supporting capacity management activities.

“This is because in the case of virtualised resources, additional components in case of a failover scenario will be easy to deploy through respective virtualisation systems,” he wrote.

Customer networks are evolving, supporting high data growths and multiple locations.

According to Roman Pacewicz, senior vice-president, offer management and service integration, AT&T Business Solutions, from 2007 to 2015, AT&T’s mobile data network grew by 150,000%. “The traditional appliance model does not scale according to Moore’s law,” he said, making the cost of networking prohibitive.

The company has been making foundational investments over the last five years, shifting from a hardware- to a software-centric network.

“We are moving our whole network to a software model,” said Pacewicz. By the end of this year, 30% of AT&T’s network will be on a software-defined network built around its Enhanced Control Orchestration Management Policy engine, EComp.   

Network functions are provided via AT&T’s OpenStack distributed cloud environment, available in multiple locations globally.

Like Verizon’s NFV, AT&T uses an on-premise appliance to virtualise network services on-site at customers’ offices, providing a gateway to its distributed cloud. This appliance virtualises four VMs for networking functions and attaches to an existing network with a gigabit interface. AT&T provides an LTE link, offering mobile connectivity to the box even if the primary link goes down.

Finally, there is a library of virtualised network functions.

Lowering the cost

Gartner research director Amresh Nandan said networks have traditionally been built to run specific services, but given the way the internet is being used in society, this way of constructing network services is no longer appropriate. “It is not enough to provide bandwidth,” he said. “Now people need bandwidth that can grow and shrink on demand, which is not possible with today’s technology.”

NFV changes network architectures from physical hardware to software running on general-purpose appliances. “This gives significant cost savings,” said Nandan. “The hardware can also be run by IT.”

With IT running NFV services, the network becomes more agile and flexible, says Nandan.

Moving from dedicated network hardware to a virtualised cloud-based model also lowers the ownership cost. “If a customer’s network needs to change, it can be changed through software,” said AT&T’s Pacewicz.

Remote management, as in AT&T’s EComp, enables IT administrators to roll out patches and new configurations to branch offices much more easily than was possible when the network was based purely on physical equipment.

Gartner’s Nandan said IT also brings DevOps to networking, which enables the network to become programmatic, giving applications the ability to request network services dynamically and providing continuous upgrades.

Arguably, as has been the case with the shift to cloud computing, virtualising existing network functions is the first step. Over time, new and innovative applications could emerge.

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