SD-WAN: At a glance

What is behind SD-WAN as an overlay network?

Due to the development from centralized IT to decentralized, agile structures and the increased use of local cloud services, company networks are being redesigned. The requirements have changed, and SD-WAN is the technological answer to this shift toward more flexible, future-proof network models.

SD-WAN networks are typically based on local internet lines and offer short paths to local clouds. As an overlay network, they can bundle a wide variety of locally available lines and access technologies (underlay) and operate them actively, for example an MPLS, Internet and LTE line. This is an ideal and cost-effective way of providing the necessary bandwidth at the location while increasing reliability at the same time.

SD-WAN is an overlay network technology. Encrypted tunneling enables routing and the implementation of security standards, even without touching the underlying underlay WAN configurations. By bundling several internet-based broadband connections, plus 4G/5G, MPLS-comparable performance and availability can be achieved, though only ever on a best-effort basis and not with clearly defined SLAs. As long as the underlay network is based on the internet, this cannot be avoided. However, several connection types can be bundled at one location, which is one approach to achieving higher performance and reliability. Unlike conventional WAN solutions, where network security is ensured via multiple appliances, an SD-WAN can typically offer all the relevant functions already integrated in the service or a single appliance, correspondingly cost-effective.

Advantages of SD-WAN at a glance

• Central management and reporting web console for the customer, cloud-based management
• Lower costs thanks to improved transport options
• Security via tunneling and encryption options
• Fast deployment through simple, standardized zero-touch deployment
• Intelligent path control: performance assurance thanks to standardized policies and application-aware networking

Provider landscape: system houses and carriers

SD-WAN solutions are available from a wide range of providers: system houses and carriers. The latter can also offer the management of the line infrastructure that most customers want. In the event of a fault or poor performance, you have a responsible contact person at the carrier, and there is no finger-pointing between SD-WAN providers, local line suppliers and subcontractors.

It is not easy to find a suitable and reliable managed SD-WAN provider among many others. There are considerable technological, price and, above all, architectural differences. In most cases, you will receive a basic or premium product from each provider.

Typical service tiers: basic and premium

Basic: Managed SD-WAN Core (e.g. Cisco Meraki) includes wireless, switching, security, intelligent network insights, endpoint management and surveillance cameras. Fully integrated hardware, software and cloud services, ideal for companies with a need for uncomplicated WAN, LAN and WLAN networks. Premium: Managed SD-WAN Premium (Cisco Viptela) serves both as a network termination for the MPLS and internet access lines and as an SD-WAN router and firewall. Network elements in series are avoided and reliability is significantly increased, ideal for companies with complex network requirements.