Why WAN availability is crucial to the cloud-first enterprise

The cloud era has morphed quickly from a handful of SaaS applications such as ERP, CRM and HR systems using cloud, to today when businesses are buying almost everything from the cloud, from compute services, contact centre software, unified communications and more.

These apps and services might look somewhat unrelated, but they have one factor in common: they are highly dependent on the network to perform properly.

Consider a consumer example. We pay Netflix money to watch a movie, but we are entirely dependent on our network connections to enjoy the experience. No matter how much more we pay Netflix, if a network connection performs poorly or is unavailable, the viewing experience suffers.

Similarly in the business world, if the network fails so will the application. In some cases it might not matter, but if it's something like a cloud contact centre service, an outage could have an immediate and direct impact on customer service.

SD-WAN to the rescue

Businesses are non-stop organisations that run 24 x 7 x 365 and any application outage is unacceptable. This requires a network with an availability that is truly 'five-nines' across both the LAN and the WAN. On pressing vendors using the five-nines term on whether their solutions truly offer that level of availability, I have usually received a bunch of caveats. Today, there can be no caveats or compromises: five-nines must mean 99.999 percent availability and nothing less.

An SD-WAN that utilises dynamic path control ensures that the WAN services and underlying transport are highly available. Instead of having to operate in an 'active-passive' mode where failing over could take several minutes, an SD-WAN can leverage multiple active connections and offer sub-second failover.

Beyond simple connectivity

Yet there's more to a network than connectivity. Another requirement is that the hardware, particularly in branch offices, must be configured for high availability. Router vendors have had this capability for decades with protocols such as VRRP (virtual router redundancy protocol) or HSRP (hot standby router protocol), but this requires buying two identical routers with one acting as a standby for the other.

This approach means that each set of routers must be manually configured and then the configurations kept in lock-step. It also requires redundancy in WAN services, requiring multiple IP addresses from each provider for both the active and standby routers. The complexity and cost have held back most organisations from doing this.

A better approach would be to apply lessons learned from the computer industry where clusters can be put in high availability mode, providing faster scale, higher uptime and simplified management. If networking transforms to software running on off-the-shelf compute platforms, then the industry can apply the same high availability options the server industry has come to rely upon.

An advanced SD-WAN solution should offer the ability to configure active/active redundant clusters without requiring redundancy of WAN services and IP addresses. A highly available SD-WAN can provide 99.999% availability of branch infrastructure and services.

In parallel, many organisations are trying to limit the amount of on-premise infrastructure, particularly in space-constrained branch offices, so building a compute cluster may not be ideal. For those businesses, a new option is emerging that leverages the power of the cloud.

There aren't many available, but one interesting solution gives customers the high availability they require with a zero-capex model by leveraging container instances that are managed via the cloud. This eliminates the need for on-premises compute and storage infrastructure to manage an SD-WAN.

More and more organisations are adopting a cloud-first model, raising the value of the network from being a tactical resource that most executives don't give a second thought, to a strategic asset that embraces the cloud with the right architecture to move their businesses forward. High availability is no longer an option, it's something organisations of all sizes must consider as part of their digital transformation strategy.

By Zeus Kerravala, founder and principal analyst with ZK Research, for Silver Peak