13 July 2017

Among some of the features to look for in an SD-WAN solution is embedded analysis and reporting that delivers single-pane-of-glass visibility into the network’s entire health.

The software defined wide area network has emerged as one of the “hottest” topics in the WAN industry, according to analysts at International Data Corporation (IDC). They believe the technology will play a key role in network evolution as organisations try to cope with the accelerating requirements resulting from digital transformation.

In a report published in June, IDC says the SD-WAN market represents a high growth opportunity for the many startups, established vendors and service providers that are now “jumping on the bandwagon”. It forecasts revenues for such firms to grow at an average rate of 92 per cent per year to reach $2.1bn (around £1.6bn) across the EMEA region by 2021.

Citing estimates from Gartner, Teneo says there are 4,000 SD-WAN deployments worldwide and that one third of global businesses will be using the technology by 2020. As part of its own research published in June, the company polled 200 UK organisations and found that 51 per cent plan to use SD-WAN to gain visibility of local network traffic and application performance issues.

“There’s been so much focus on strategic digital transformations in recent years that we’re in danger of forgetting the importance of customer responsiveness to companies’ regional and branch-level lines of business,” says Teneo CTO Marc Sollars. “SD-WAN’s ability to show what’s going on at grassroots gives UK CIOs a realistic way to ‘think global and act local’ with their network infrastructures, especially as their IT resources are likely to be tightly constrained for the foreseeable future.”

So does SD-WAN represent the future of enterprise networking? Chris Gilmour, pre-sales manager at Axians Networks UK, says networks have not evolved as rapidly as what’s running over them. “You tend to find that we are using MPLS technologies that have been around for 10 plus years, and they’re mainly network centric technologies. SD-WAN is about isolating and separating traffic out rather than handling traffic in a different way.”

According to Gilmour, the idea of the SD-WAN was mainly driven by open networking groups who are heavily enterprise focused. He explains that they wanted to try and bring the flexibility of SDN within a data centre to the network, and to also make it transport-independent. 

“Basically, if you’re a service provider you’re very interested in how the network operates. But if you’re an enterprise, the network could be wet string with two cans on the end of it. Enterprises don’t care how their applications are delivered as long as they perform the way they want them to. 

“That’s where SD-WAN comes in. It is application-centric and enterprises care about applications, they don’t care about the network. So the service providers are now having to play catch up because a lot of business customers are asking them ‘what SD-WAN solutions have you got?’”

SD-WAN comprises many existing technologies such as real-time analytics, policy-based routing, zero-touch provisioning, centralised orchestration, amongst others. WAN optimisation and acceleration also play a part, which is why it is not surprising to find companies that have specialised in these areas – such as FatPipe, Riverbed Technology, Silver Peak, Talari Networks, et al – now occupying the SD-WAN vanguard.

With business now facing different demands in a rapidly changing marketplace, SD-WAN offers a better approach to networking across the global enterprise, according to Steve Foster, senior solutions engineering manager, Riverbed Technology. He says that as more businesses adopt cloud computing and services, there is a need for an end-to-end software-defined connectivity infrastructure for the entire enterprise with virtualised functionality that can be orchestrated across cloud networks, remote LANs and hybrid WANs. 

“The router-heavy, hard-coded, complex networks of the past simply cannot easily support digital services, the mobility of the masses, or the rapid rise of data in today’s hyper-complex IT environments,” says Foster. 

Silver Peak supports this view. It says that as businesses migrate applications and infrastructure to the cloud, legacy WAN architectures are proving “inefficient and ineffective” in connecting users to applications. Nick Applegarth, the company’s VP, says: “While reliable when applications were hosted in the data centre, legacy architectures are costly and complex to manage. They impair application performance due to the inefficiencies of consuming WAN bandwidth to backhaul all cloud destined traffic through the data centre.”

Atchison Frazer, worldwide head of marketing at Talari Networks, agrees when he says public cloud computing rendered traditional WAN architectures “obsolete”, while digital business transformation has increased the sense of urgency. “Enterprise WANs are mired in a complexity and cost vortex. SD-WANs drive cost-efficiencies and agile methods in contrast to brittle, slow, fragile and static networks. They also improve performance for all apps, including ones that are cloud-resident and cloud-centric, and offer a better managed WAN run model with opex over capex.”

Ultimately perhaps, SD-WAN is about creating optimised enterprise networks that offer increased agility and simplicity. Foster says it provides improved and secure internet connectivity that puts the control back with the network administrator, and provides the ability to identify and address service issues. Applegarth adds that another big benefit of building an SD-WAN is that enterprises can transition at their own pace in alignment with the changing requirements of their businesses. 

Making the transition

The idea of software defined networks has been around for a while now, so why not simply just talk about SDN rather SD-WANs? Anders Hellman, principal member of technical staff, SDN and IP products, at Verizon EMEA, says the most important differentiator is the separation of the control plane from the forwarding plane.

“The control plane can steer the traffic based on policies, defining what applications, or application groups should use which preferred path through the network.

“This enables what is one of the major drivers for SD-WAN – more consistent and faster central control for steering of the traffic paths in the network from central controllers, whereas the underlying network just has to forward the traffic.”

As a result, Hellman says SD-WAN can be transport agnostic and can be run as an overlay across, for example, public and private IP, LTE, etc.

Foster points out that although it may seem like there’s little difference between SDN and SD-WAN, the latter needs to tackle a different set of challenges. These include connecting an enterprise’s data centres, branches and remote workers on a global basis with SaaS and hybrid cloud applications using a combination of MPLS and internet services. He says: “SD-WAN architecture automates the process of joining the networks plus selecting which service to use depending on business requirements so that both private WAN and public internet can be utilised efficiently.”

He goes on to state that SD-WAN offers cost advantages over traditional networking. These include a reduced hardware footprint when implementing network functions on consolidated appliance platforms, plus holistic and centrally controlled management of low cost internet services, resulting in reduced or frozen investment in expensive MPLS. 

Frazer points out that SD-WAN represents the best way to transform the edge enterprise network into the cloud-ready age in which more data and apps run in a hybrid-cloud fashion. Gilmour expands on this by saying that the intelligence is really on the edge with all the network configurations sent out from a central point. He says this approach then enables netadmins to put in a new site very simply and quickly. They have the ability to control how individual sites react and how individual applications are handled across that network.

“SD-WAN gives you site-by-site visibility of what applications are going over your network, how much of your available bandwidth they take, and also tells you about the condition of the individual parts. All of those things are then pulled together to allow you to direct individual applications down specific parts of the network to optimise the performance.”

So how should netadmins go about making the switch to an SD-WAN? Or perhaps the question should be, when should they move especially, as the old adage goes, if it ain’t broke why fix it?

Aside from SD-WAN’s new functionalities, Axians’ Gilmour says there are some basic features that will be of benefit to many enterprises today. And he adds that a lot of that is about harnessing the bandwidth they have available for their sites. 

“We’re working with a customer who has a number of DSL links into each of their locations. They have a link dedicated to data, and another one just for voice which is used a lot and is sized based on the number of SIP links needed. While all the phones aren’t in use at the same time, the data link is being absolutely hammered. So the customer may have to upgrade the data links and wants to try and keep the traffic separate to allow for the fact that it is already experiencing congestion. 

“But by adding SD-WAN, the customer could pool those links together. The downtime it has for the voice links will allow extra flex for the data connectivity. So it would end up with a lot of available pooled bandwidth today without changing anything in the infrastructure at all.”

FatPipe Networks – which claims to have invented the concept of SD-WAN and hybrid WANs – warns enterprises to make sure that any SD-WAN solution they choose should be around for the lifecycle of the product. Matt Gwyther, the company’s technical marketing manager, says: “With the large number of SD-WAN companies right now, there are going to be some that do not make it and some that are acquired only to have their products eliminated. The enterprise therefore needs to be confident that the solution provider is not simply a startup and has the longevity and proven real-world experience to support them.”

Riverbed’s advice for enterprises implementing an SD-WAN solution is to look for a cloud grade service. “Today, the landscape for housing and delivering business applications is incredibly diverse, spanning traditional data centres, cloud environments, remote branches and mobile users,” says Foster. “Consequently, your SD-WAN solution must expand to handle automated connectivity and orchestration across hybrid WANs, cloud networks and remote branch LANs/WLANs. This expansion is critical to achieving significant gains in agility and operational efficiency.”

Foster continues by saying many SD-WAN solutions offer basic monitoring while modern hybrid networks require far more depth. As a result, he says users have to make sure that they’re equipped with advanced application and transaction insight in heavily-encrypted environments, comprehensive end-user experience monitoring, and deep network intelligence to provide total visibility into application performance and fast resolution of problems. 

Optimisation is another area to watch for: “Point-product approaches to combining WAN optimisation and SD-WAN network services compromise control over application performance as packets move between WANOP and SD-WAN functions,” says Foster. “Look for a single solution that unites these technologies across hybrid WANs, cloud (SaaS, IaaS, PaaS) networks and branch LANs/WLANs, plus one that provides automated and dynamic path selection.”

For Silver Peak, the first thing you need to decide when migrating to an SD-WAN is whether to employ physical appliances or virtual ones running in all branch locations that will be part of the network. In either event, Applegarth says the solution should offer encrypted tunnels and provide high levels of performance, security and segmentation from edge-to-edge.

Moreover, he says netadmins should carefully evaluate how robust each solution’s path conditioning capabilities are to monitor and manage packet loss, out-of-order packets, latency, jitter and throughput to ensure that applications perform in alignment with SLA thresholds. “This is important, especially when using internet connections and even MPLS, because path conditioning reconstructs lost packets or out-of-order packets in transit without incurring the overhead or latency of retransmitting them.”

Masergy launched a managed SD-WAN service last September. Paul A. Ruelas, the company’s director of product management, says that if enterprises want the highest performance SD-WAN environments, they should seek out solutions that offer forward error correction and application-based routing. FatPipe’s Gwyther adds a caveat here by saying that many providers simply duplicate traffic across multiple links which creates bandwidth issues at the data centre. “Enterprises should be mindful of what packet duplication/forward error correction techniques the SD-WAN product is offering to see if it fits in their network requirements.”

Network visibility is one of SD-WAN’s defining characteristics and certainly crucial for Verizon. Earlier this year, it announced a partnership with digital infrastructure management software specialist SevOne to deliver added visibility into SDN services. With the new capabilities, Verizon claims its enterprise clients benefit from a singular view that spans multi-vendor technology without the burden of managing disparate monitoring systems. By using an integrated web interface, it says clients gain an end-to-end view of services spanning the physical and virtual network.

As providers of managed SD-WAN platforms, both Masergy and Verizon believe outsourcing is the solution network managers should go for if they want to mitigate the risks and expenses associated with deploying any new technology on their own. Ruelas says: “Use the expertise of a proven service provider whose offering doesn’t lock you into a single hardware or technology approach which can prohibit interoperability with your business’ broader WAN platform. The right service provider will do the heavy lifting for you to ensure rapid deployment, simplified change management, and real-time analytics and service control. You’ll also be able to eliminate many of the high capex costs associated with proprietary network appliances.”

Verizon adds to this by saying that along with the many benefits of hybrid WAN comes additional complexity to policies and templates that administer security. Hellman says: “While organisations want to adopt hybrid platforms, many may not have staff with the expertise needed to manage the risks that come with that added complexity. Using a managed service can support a business’ switch to SD-WAN and help them move forward confidently, as many of the more complex requirements are taken care of by the organisation providing the service.”

A ‘fit and forget’ network?

Hellman was not the only one to express concerns about skills shortages. For instance, Riverbed’s Foster says developing new skills to ensure that groups such as applications, servers, security, storage and networking are collaborating and no longer working in ‘silos’ is crucial. “A great contributor to removing the barriers of collaboration is having a common management and monitoring platform that can be used by all teams, providing a single source of truth regardless of their individual skill set.”

As a precursor to this, Foster says ensuring that IT staff are completely on board with every aspect of moving to a virtualised and centrally orchestrated environment is critical to success. “They must have a full understanding of how the existing application delivery works, and it is important to draw on that experience after the transition to ensure continued consistent user experience. Members of staff running this part of the operation are as important as the management in this exercise.”

Teneo’s research supports this approach. It found that UK CIOs still face serious resourcing and skills gaps as they try to reconcile their global and local network infrastructure needs. Twenty nine per cent of its survey respondents stated that a lack of team resources and skills to monitor local networks was one of their top three networking challenges.

“Networks are so complicated now that CIOs need a practical way to deal with branch-level application issues alongside global needs,” says Sollars. “The trouble is, they don’t have the resources for locally-based troubleshooting or running regional networking teams to ensure high-performing applications 24/7.”

The other challenges identified by CIOs in Teneo’s study included high management costs for divisional and branch IT networks (40 per cent) and high network upgrade costs in general (35 per cent).

Clearly, SD-WAN is not a ‘fit-and-forget’ networking solution, and despite all its potential, hurdles remain. 

Foster points out another key challenge for IT teams is managing the multiple WAN providers that results in deploying a hybrid SD-WAN. “SD-WAN will still require traditional WAN services, be it MPLS, internet, DSL, etc. So network administrators will need to be managing those contracts and services whilst creating and managing their own SD-WAN to bring them all together. At the same time, they will have to interpret the different business needs and correlate this with the connections needed from the networks.”

In the past, Foster says a network manager had to work with services such as firewalls, VPNs, WAN optimisation and the wealth of complex configurations that came with them. He reckons that’s where solutions like Riverbed’s SteelConnect comes in, as it replaces the pains of WAN management complexity with cloud-era IT agility and single-click creation of multi-service SD-WAN capabilities in the cloud.

Planning for the unplannable

Given the fact that SD-WANs are multi-service environments, Masergy reiterates that companies should ensure they do not choose a provider that locks them into working with a particular vendor, thereby ruling out mixing and matching solutions. “Seamless interoperability with other vendors’ circuits and WANs, and the ability to connect any location over any transport method, are fundamental functions of a truly flexible and risk-free SD-WAN,” says Ruelas.

Talari’s Frazer also warns against vendor lock-in: “For example, some vendors require specific carriers when they move you from MPLS, and some only offer traditional WAN-optimisation, but no real software-defined, controller-based, platforms.

“Furthermore, unless your vendor measures performance and routes dynamically at the packet-by-packet level in real time (milliseconds) as opposed to the session-steering of bulk packets with round-trip measurement only, attempting to run SD-WANs for real-time latency-sensitive apps such as VoIP or video-conferencing will be severely challenged.”

Ruelas says it’s also important to realise that in most cases, SD-WAN isn’t a complete MPLS replacement in favour of “best-effort” broadband. He warns that upload speeds may be constrained when using SD-WAN purely over broadband internet. 

Gwyther adds to this by suggesting that there is a narrative that multiple broadband connections are just as good as MPLS. “While in some situations this is true, in many it is not. Enterprises need to be mindful in selecting their access, especially when VoIP or other real-time applications like video-conferencing are the main network applications.”

Ultimately though, all this is just the type of fine detail you would expect when deploying any type of complex enterprise network, and the arguments in favour of migrating towards an SD-WAN environment remain compelling. Axians’ Gilmour sums it up neatly when he says: “SD-WAN offers benefits for today as well as for the future, where organisations are able to plan for the unplannable and look at designing the network for things they don’t even know they need as yet.”