SD-WOW! Software defined WAN is the Formula 1 of Networking

Those of you that know me know I love all things NetScaler, so when Citrix recently told me about a feature that sends packets across multiple paths in a ‘race’ to their destination, they had my undivided attention.

Packet ‘racing’ sounded like my ultimate geek feature, and I wasn’t disappointed. My immediate vision was of F1 cars, ironically...

Brief Background

Citrix is the only vendor focused entirely on end-user experience and all Citrix products are designed and developed around this core principle. Citrix introduced WAN optimisation to their comprehensive portfolio of end-to-end products several years ago and I had the pleasure of deploying 44 WAN Op appliances on the sunny island of Mauritius back in 2010. It wasn’t the worst place to be working by any stretch of the imagination, but believe me, it was long hours and very challenging, and at times the broader technology didn’t work as planned and it took a while to get everything operating smoothly.

Technology has come a long way since 2010 and deploying traffic optimisation products can be as simple as zero-touch today. Easier deployment is partly why SD-WAN is such a focus for rhipe and our partners, and with industry analysts touting that SD-WAN adoption will grow by 60% by 2019, all partners should be giving it serious consideration in order to stay ahead of their competition.

Traditional WAN-Op

WAN optimisation is more commonplace today and it’s obvious that due to its ability to compress, de-duplicate and cache traffic, it offers far superior performance when compared to the basic quality of service or simply increasing bandwidth. Cloud services are also driving demand for better connectivity as digital transformation drives more data to the cloud, and critical business processes require optimal performance for services that were previously located locally, making the WAN more important today than it has ever been.

Fast Fact: Public Cloud services are the source of 44% of enterprise traffic!

The NetScaler SD-WAN platform includes both WAN Optimisation and traditional SD-WAN capability, i.e. the aggregation of WAN links. In simple terms, WAN aggregation is the logical grouping of multiple WAN links. This logical grouping of links allows traffic to be sent optimally based on numerous network metrics including utilisation, latency, jitter and packet loss.

Using SD-WAN, traffic can be routed across the optimal path(s) or across a specific path based on policies. For example, print traffic can be heavily compressed and sent over the slowest link while voice and video can be sent over the fastest link, that is no longer bogged down by print traffic. Additionally, backup links that were previously only used for failover can now be used all the time, creating a return on an investment that wasn’t previously possible.

What is SD-WAN?

The Open Networking Foundation describes software-defined networking (SDN) as an architecture that “decouples the network control and forwarding functions, enabling the network control to become directly programmable and the underlying infrastructure to be abstracted for applications and network services.” This architecture allows networks to be centrally managed, programmatically configured, and dynamically adjusted as traffic flows and application requirements change.

Software-defined wide area networking implements these concepts by binding multiple MPLS, mobile, and broadband paths into a single logical path. The physical paths can include MPLS circuits, broadband cable and DSL connections, and 4GE LTE connections. Application traffic is optimised across the multiple physical paths and dynamically adjusted to provide the highest possible quality of service for high-priority applications.

Figure 1 shows a simple example of a SD-WAN connecting a data centre and one remote of office.

What are the core features of Citrix NetScaler SD-WAN?

Intelligent Path Selection

NetScaler uses Intelligent Path to dynamically change the path of traffic in order to ensure optimal delivery of each packet across the WAN. The best path is calculated constantly and is bi-directional, so using broadband connections that can have faster download speeds and slower upload rates doesn’t impact on performance.

NetScaler SD-WAN appliances deployed at each end of the WAN communicate the performance of all paths to each other so that when a connection is initiated, the appliances can send the traffic across the best path available.

Of course, we all know network performance is never constant. One of the key objectives of SD-WAN is to dynamically change how the traffic is managed based on the network performance and the requirements of the traffic being managed. To achieve this, the source appliance tags every packet it sends and records the transit time for each packet sent. By looking at the tags for a sequence of packets, the destination appliance obtains information on packet loss, jitter and latency associated with the path.

The destination appliance then shares this performance information with other SD-WAN appliances and this allows all the appliances to continuously know the optimal path for sending packets.

Fast Failover

If packets are missing, the NetScaler SD-WAN Fast Failover feature moves traffic to the best remaining path in milliseconds. Employees and customers won’t realise that an interruption has occurred; their VoIP/video calls or Citrix sessions won’t show signs associated with a network outage.

The ability to cope with outages of this nature helps create a premium service with unparalleled performance. This is one of the key value propositions of SD-WAN and all customers want to avoid outages and experience good and sustained performance.

Scalability and cost reduction

Software defined WAN can also help reduce costs; both WAN circuit costs and those associated with maintaining networks, outages and poor WAN performance.

Broadband connections and mobile connections can, of course, perform indifferently at times, but multiple circuits will rarely have issues at the same time.

NetScaler SD-WAN can move traffic to an optimal path dynamically, so multiple broadband connections can provide the same quality of service as an MPLS circuit. With VoIP, Skype and other WAN traffic growing, businesses can add additional capacity quickly, easily and at low cost, by using broadband connections instead of expensive MPLS circuits.

Gartner predicts that SD-WAN can reduce the cost of WAN by at least 40%. The lower cost of hardware, software and support of the WAN all add to the broader benefit of deploying SD-WAN.

Reference: Gartner: Technology Overview for SD-WAN, July 2015. For Gartner’s perspective on SD-WANs, see also I hate my WAN...SD-WAN to the rescue.

Prioritisation and Quality of Service

The Quality of Service (QoS) controls provided by NetScaler SD-WAN can be used to categorise different classes of applications, and for specific applications. Administrators can assign applications to the three primary categories: real-time, interactive and bulk. If more granularity is needed, custom categories and rules can be created based on metrics like source and destination IP, protocol, source and destination ports and QoS tag.

This level of control means critical applications and sessions can be given priority over all other applications or the same priority as other real-time applications including video conferencing or Citrix XenApp/XenDesktop sessions.

Prioritisation provided by NetScaler SD-WAN is dynamic. For example, VoIP sessions are initially given the best performing and highest quality paths, but if a path slows down or experiences excessive jitter or packet loss, NetScaler SD-WAN moves the traffic to the best possible path with zero perceived impact to the call.

Packet Duplication (packet racing)

So here we are, at the feature that I’ve been raving about for the last two weeks. Mission critical traffic like Skype for Business VoIP and video can be configured to traverse independent paths in a race to their destination. The first packet received is the optimal packet and is used by the NetScaler SD-WAN appliance, with the subsequent packet dropped. The winner of the race is of course the optimal packet and will provide the very best user experience.

Packet duplication uses more bandwidth but it assures excellent quality for the most important applications. The duplication technique also results in sessions with zero packet loss, except in rare events where both paths drop the same packet.

Packet duplication, QoS and other performance-enhancing features provided by the NetScaler SD-WAN solution ensure high reliability and high quality for traffic with any mixture of MPLS and broadband connections – even when the quality of the individual paths is not uniformly high.

SD-WAN as a Service

SD-WAN as a Service is a great opportunity for partners wanting to tap into the excellent predicted growth opportunity the technology presents. Coupled with existing services, SD-WAN creates additional sticky business with high-quality outcomes and long-term revenue prospects.

I like to think of SD-WAN as the premium overlay for any IT service - it’s the crème de la crème of IT services. Whether you’re hosting services, reselling publicly hosted services or managing customer platforms on customer-owned networks, SD-WAN as a Service still provides the same customer benefits and partner opportunity.

I’m helping partners win business with networking services today and there’s no doubt the current gap in the SD-WAN market is a real and present opportunity for partners to create sustained and profitable revenue streams.

Go to Market

SD-WAN isn’t expensive, and based on the reduction in the cost of networks and improved performance, productivity and network simplification, it’s an extremely compelling solution and it’s easy to sell. Citrix Sales IQ includes information to help existing Citrix partners productise and go to market with SD-WAN or any Citrix product. There’s also an ROI calculator to help partners with their sales strategies.

More Information

Partner Kit for SD-WAN

WAN Optimisation with NetScaler SD-WAN

Existing Citrix Partners can access the following gated content via your Partner Portal

ROI Calculator

Customer Overview

Partner Playbook for Selling and Positioning

Product Training – Enablement Content (enablement.citrix.com)