Just what is SD-WAN?

Everything You Ever Wanted to Know About SD-WAN

Published: 14th June 2016

Software-defined WAN (SD-WAN) is an approach to designing and deploying an enterprise wide area network (WAN) that uses software-defined networking (SDN) to determine the most effective way to route traffic to remote locations.

But is SD-WAN the right solution for your business? If you’re always firefighting MPLS issues or struggling with network speed then it definitely is! Not only will it solve these problems but it will also help you to dramatically reduce costs too - by up to 90%!

We’ve brought together some commonly asked questions about SD-WAN that should tell you everything you need to know, and make the decision-making process simple!

Deliver at least MPLS-level reliability and application performance predictability
Q: Does the SD-WAN solution offer sub-second response to network problems—not just link failures but even network brownouts, or periods of high packet loss and excessive jitter?
A: Yes. Even better we offer zero second failover - Ultra Resilient Mode.
Q: Are end-user connections (TCP flows) terminated when traffic has to be moved from one link to another, or are the sessions maintained?
A: We are a packet based solution so the flow is maintained regardless of whether one of the physical links are down.
Q: Can 4-nines (99.99 percent) reliability and performance predictability be delivered if only Internet connections are used?
A: Yes, we can provide 5-nines as opposed to 4.
Dynamic support of multiple active links
Q: Are more than two links per location supported? If so how many?
A: Yes, we support 4 right now but in 8.1 there will be no limit.
Q: Can a single flow be striped across multiple disparate links, allowing all available bandwidth to be used even for just a single active large transfer?
A: Yes
Q: Is each flow limited to a single connection?
A: No
Q: Can all links be used whenever they are working, or are certain traffic types designated for certain connections in the absence of a network event for that connection?
A: Yes all links can be used.
Efficient use of each WAN link, both inbound and outbound
Q: At what percentage utilisation can links with traffic inbound from multiple locations be sustained while still delivering predictable application performance?
A: Subjective but much more than 40%.
Q: If the answer is greater than 40 percent, how is this done?
A: QoS, data reduction, FEC, POC etc.
Q: Can it be demonstrated?
A: Yes
Q: Can business priorities and policies be enforced to ensure critical application traffic always has an adequate share of network resources?
A: Yes
Support for real-time apps in real time
Q: Can the SD-WAN solution deliver 4-nines reliability for real-time applications, even if private MPLS bandwidth alone is insufficient?
A: Yes
Q: Can real-time application quality be maintained with an all-Internet WAN?
A: Yes
Q: How is this done?
A: FEC, POC, Ultra Resilient mode and Boost.
Secure and reliable access to cloud services and SaaS
Q: How is performance and reliability for SaaS and public cloud services traffic assured?
A: Full optimisation.
Q: Can we maintain our existing centralised security model, or does the SD-WAN solution require a migration to a decentralised security approach?
A: Yes you can maintain your existing security model.
Non-disruptive augmentation of existing enterprise WAN
Q: Does the solution work with our existing MPLS WAN?
A: Yes
Q: Does all of the functionality work across the MPLS connections, or is it just a subset of that offered over Internet connections?
A: Across everything if so desired via Business Intent Overlay.
Q: Can the solution aggregate MPLS and Internet connections so a single session can simultaneously use both forms of network?
A: Yes.
Q: Does the solution work with our existing WAN optimisation appliances?
A: Yes, but you can replace that solution when depreciated if required.
Ease of use and ongoing manageability
Q: Does the SD-WAN solution offer extensive network-level and application-level visibility and reporting?
A: Yes
Q: Does the approach not only report on, but also mitigate network problems in real time?
A: Yes
Q: How easy is it to add a new location to an existing WAN?
A: Zero-touch!
Q: Can changes be made during business hours without disrupting network operations?
A: Yes
Ability to scale
Q: How large an SD-WAN network can be built? How many locations? How many WAN links?
A: In this version a full mesh of 4 million tunnels or 2000 sites. Next release will be 16 million tunnels and 8000 sites.
Q: What are the vendor’s largest actual deployments?
A: 400 sites.
Q: Can we talk to other customers with a deployment the same size?
A: Yes

If you have any further questions about the SD-WAN-as-a-Service solution please click here or give us a call on 08456 118 811.