SD-WAN: How DDI Simplifies Deployment and Operations

SD-WAN was born as Enterprises needed cheaper bandwidth and more nimble ways of deploying and operating WAN networks especially with the requirements of Digital Transformation. Although SD-WAN delivers on its promises, most solutions on the market do not fulfill all the services that were rendered by traditional MPLS services, like for instance IP Address Management (IPAM).

While providing some subsets of its features, SD-WAN solutions lack Integrated DDI (DNS-DHCP-IPAM) as a whole, especially DNS services. And while SD-WAN is protocol aware, steering traffic by leveraging application level attributes on the multiple available paths, it is not application aware and therefore won’t adapt to the intricacies of the application infrastructure. By the same token, while being path aware (one of its key features) SD-WAN is not destination aware preventing falling back on alternate resources if need be.

DDI ideally complements SD-WAN solutions, by orchestrating underlay and overlay networks IP addressing and DNS capabilities to simplify deployments, and by proposing destination-aware routing for improving reliability, app performance and UX.

Challenges of SD-WAN

From the traditional MPLS to SD-WAN networks solely built on top of the Internet, the main difference is that connections between sites across the Internet require overlay routing and thus management of multiple IP address plans (underlay, overlay, etc.). IP address management was part of the MPLS services, delivered and operated by the CSP, therefore such skills were becoming less needed and so are now less available among IT/Network teams within enterprises. With SD-WAN, whether consumed as an integrated solution or as a managed service, the customer needs to reinvest in managing multiple IP address plans.

SD-WAN is suited for large, even massive site deployments, especially in industries such as retail. This requires rigorous planning and inventory management and thus the integration of strong documentation tooling, which is often not included or not exhaustive enough in the SD-WAN packages.

None of the SD-WAN solutions are interoperable, which leads to vendor lock-in and can become an issue when merging networks operated with different solutions in the case of a M&A for instance. In this situation the customer will need to figure out a way to consolidate the two networks without getting the full picture from either of them. The best way to prevent this, deploy and streamline multi-SD-WAN vendors/MSP networks, is to make use of an external IP data repository, agnostic to the SD-WAN solutions, giving a unified picture of the IP infrastructure independent of the vendors’ representation and tools. This would become handy when the time comes to change suppliers or at least to threaten doing so…

As obvious as it sounds SD-WAN solutions do not provide DNS services as they are usually not in the scope of the strict network infrastructure and spill over IT as well. So, for any application or service, SD-WAN requires DNS services to find the best destination IP addresses and from there provide application traffic steering over the multiple available paths using sophisticated algorithms factoring Layer 4 to Layer 7 attributes on top of paths’ real time metrics such as capacity, QoS, security, confidentiality, etc.

As explained previously, SD-WAN understands application protocols. Nevertheless SD-WAN does not understand the Application Infrastructure and cannot find an alternate destination when the nominal one (IP/server/DC) is no longer reachable or when the selected path does not comply anymore with the applications requirements. Therefore SD-WAN needs to be augmented with an over-the-top DNS solution being able to propose such alternate destinations in Multicloud and Disaster Recovery Plan use cases.

How DDI Benefits SD-WAN

MPLS services, as costly as they are, do not provide only connectivity and bandwidth. Among the other integrated and managed services, IP Address Management is essential to run and scale a network, or to merge and consolidate many. Also, even though not included in the native list of features delivered by SD-WAN, efficient DNS services and security would extend SD-WAN capabilities.

The market-leading DDI from EfficientIP brings the following value to SD-WAN:

• Comprehensive visibility of the IP infrastructure
  A consolidated “IP source of truth”, independent of the way the SD-WAN solution represents it, allows to have a clear picture of the deployment to be made or already achieved. This is essential to evolve, scale, or merge the IP infrastructure. This is like having the blueprint of a building’s electrical infrastructure. Without it, you can forget about expanding it easily and safely.
• Accelerate sites rollout and operations
  SD-WAN provisioning of sites can be integrated with IPAM provisioning, leveraging metadata for automation & integration with network, security and applications ecosystems, starting with the SD-WAN orchestrator.
• Enable SD-WAN vendor independence
  Allows blended SD-WAN infrastructures without vendor or managed service provider lock-in by consolidating the whole IP repository including the IT infrastructure.
• Complement the SD-WAN infrastructure with DNS Services and DNS Security
  DNS would find the best IP destination for Multicloud and Disaster Recovery Plan use cases factoring predefined policies and real time constraints on availability of the resource, network latency to reach it or overall service’s response time.
• Enhance service continuity, strengthen resiliency and improve UX & app performance
  In Multicloud and DRP scenarios if the nominal destination is no longer reachable using SD-WAN fallback algorithms, Edge DNS GSLB would find alternate destinations for which reachability can once again be secured by SD-WAN multipath schemes providing an extra layer of resiliency.

Example Use Case

A global retail brand rolling out an entirely new SD-WAN network to support the business and monetic applications while also providing guest Wi-Fi at point of sales would require an IP address management solution with an asset repository to manage and control not only the initial rollout but also the change management as part of day to day operations.

DDI complements SD-WAN

Nowadays SD-WAN and Cloud based applications call for a common repository to describe and operate the IP infrastructure. IPAM is the single IP source of truth SD-WAN needs to go beyond the network boundaries and is the way around SD-WAN vendor lock-in. As DNS Services and DNS Security are still needed to complement SD-WAN features, having them integrated as part of a DDI solution makes sense. To top it all off, even though SD-WAN is path aware, it is ideally completed by Edge DNS GLSB for mission critical applications in Multicloud and DRP contexts to further enhance service continuity and improve UX & App performance.

SD-WAN is now part of a bigger framework called SASE (Secure Access Service Edge). Within SASE, SD-WAN provides WAN connectivity, while other services take care of various security aspects. For both SD-WAN and SASE it all starts with DDI.