With significant global growth predicted over the next three years, UCaaS and SD-WAN are two of the hottest and most interesting technologies in the telecoms market right now. Through our many customer engagements and vendor interactions, The Network Collective has developed excellent market insight in relation to the key strategic considerations when designing an SD-WAN to support UCaaS.

The objective of this whitepaper is to present an overview of the key strategic considerations for organisations when designing and sourcing SD-WAN to support UCaaS.

1. MPLS replacement
vs. hybrid overlay

Many organisations consider SD-WAN with an internet underlay to be a complete replacement for MPLS. In some cases, this is entirely possible, particularly if application workloads have been migrated to public cloud services and there is limited requirement to guarantee real-time applications such as voice and video. However, for many organisations the need to guarantee quality and performance for real-time applications remains a key requirement. For these organisations, an SD-WAN design with a hybrid underlay model, where MPLS and Internet co-exist to provide both quality for real-time applications but also direct access to public cloud services, should be considered

2. Hub and spoke
vs. full mesh SD-WAN design

No single SD-WAN solution is created equally and there are many variables such as estate size and logical segmentation which could drive a different SD-WAN low level design. One such design consideration is whether to configure a hub and spoke or full mesh SD-WAN architecture. When is comes to the voice and video components of UCaaS, it is important to consider the traffic path between two end points. For example, in a hub and spoke design the traffic path would need to traverse the hub site to initiate and stream the data, whereas in a full mesh deign a direct path could be established

3. Guaranteed QOS
vs. Engineered QOS

UCaaS interactive components such as voice and video are intolerant to delays or losses. Traditionally, organisations would configure QoS in their MPLS networks to provide better throughput, minimise delay, and ensure less packet loss and jitter in real-time packet delivery. However, as networks have improved, and higher bandwidths have become more affordable, some organisations are beginning to move away from traditional QoS policies in favour of a “best endeavours” approach. SD-WAN adds some real value here; features such as dynamic path selection, performance-based routing, and congestion control help organisations engineer a QoS policy which optimises the routing and packet delivery based on application parameters and network conditions. Be cautious though - even with the best traffic engineering available, the network is only ever going to be as good as the underlay can provide. If voice and video is a critical application to your organisation, think very carefully about the risks of the engineered approach

4. DIY vs. Managed Service

Very often many of the key considerations for SD-WAN are of a technical nature and the sourcing approach and target operating model often don’t get the focus they require. As of today, the SD-WAN market is overcrowded with vendors entering from WAN optimisation, routing, security, and start-up backgrounds. Couple this with the plethora of telcos, Systems Integrators, and SD-WAN MSPs productising vendor solutions and/or offering proprietary solutions, and you are left with a significant number of options to source and support your future SD-WAN. To help the selection process for SD-WAN, TNC believes the sourcing approach and the target operating model should be considered up front and some key principles defined around commercial model, asset ownership, service boundaries, change and incident management, and service reporting

5. Total cost of ownership

As with any infrastructure investment, having a clear view of the total cost of ownership and return on investment is key. There has been lots of marketing hype suggesting SD-WAN will deliver significant cost reductions. However, TNC’s research shows that, whilst in theory cost reduction is possible, the reality is that most deployments of SD-WAN overlays in isolation will only ever increase costs. To break even or deliver a cost reduction, significant time and effort will be required to re-architect, source and implement an alternative “cheaper” underlay network and, where applicable, converge peripheral services such as WAN optimisation and firewalls into the SD-WAN solution. As a strategic initiative this approach will suit many organisations. However, from a TCO and ROI perspective the short-term costs are likely to increase, and the ROI take longer to achieve

To help customers with the strategic planning and preparation for SD-WAN and UCaaS, TNC has developed a strategy development framework to assist customers at each step of the sourcing lifecycle; business case creation, statement of requirement development, option analysis and sourcing strategy.

If you would like to find out more about how we can help you on your SD-WAN and UCaaS journey, we would be delighted to talk to you and share our experience and knowledge.

TNC supports the sourcing of network and telecoms services for 20% of all major corporate organisations in the UK


Other than matters relating to The Network Collective, this research is based on current public information that we consider reliable. Opinions expressed may change without notice and may differ from views set out in other documents created by The Network Collective. The above information is provided for informational purposes only and without any obligation, whether contractual or otherwise. No warranty or representation is made as to the correctness, completeness and accuracy of the information given or the assessments made.

This research does not constitute a personal recommendation or take into account the particular investment objectives, financial situations, or needs of individual clients. Clients should consider whether any advice or recommendation in this research is suitable for their particular circumstances and, if appropriate, seek professional advice.

No part of this material may be (i) copied, photocopied or duplicated in any form by any means or (ii) redistributed without the prior written consent of The Network Collective Limited © 2022

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