SD WAN is the dominant network connectivity employed by enterprises, with 67% using SD WAN to connect branch offices, retail stores and manufacturing sites to clouds, data centers, web and SaaS applications. MPLS to SD WAN migration is accelerating: MPLS network connections are declining by 24% annually, while SD WAN deployments are increasing by 240%. SD WAN migration is a business-critical project. With 80% of applications hosted on the cloud, and 72% of them interconnected with other systems and applications, network connectivity is the largest contributor to application performance and user digital experience degradations.* With business and employee productivity dependent on connectivity, enterprises need an SD WAN migration plan that prioritises performance and IT operational efficiency while keeping delays, cost overruns and risk to a minimum. This article covers the key steps to a seamless SD WAN migration keeping these factors in mind.
SD WAN Migration Challenges
SD WAN depends on internet performance that comes without performance guarantees. Internet providers’ peering arrangements, regional coverage, DNS resolution performance and BGP routing performance across autonomous systems (AS) outside of their control all impact SD WAN performance. As a result, SD WAN combines SD WAN underlays from multiple internet service providers to increase resilience and bandwidth, and to improve routing options for latency-sensitive private, SaaS and web applications. The majority of enterprises also combine SD WAN with CASB security platforms which can also impair performance.
Despite these highly dynamic underlying performance drivers, SD WAN vendor’s integrated performance monitoring tools don’t provide sufficient insight to understand the end-to-end connection between users and applications, data centers and clouds, and are unable to diagnose underlay performance issues. Legacy network performance monitoring (NPM) tools that rely on traffic analysis are ineffective in decoding encrypted traffic to SaaS applications and the cloud to analyze network routes and performance metrics. It’s essential for enterprises migrating to SD WAN to have consistent network performance visibility across all steps in their SD WAN migration to overcome these SD WAN migration challenges.
| SD WAN Migration Challenge | Origin |
| Underlay ISP performance issues | Internet provider(s) |
| Suboptimal DNS resolution | Internet provider(s) |
| ISP performance and BGP routing | Internet provider(s) and their peering partners |
| CASB / cloud proxy delays | CASB / SASE provider |
| Application-Based Routing | SD WAN Configuration |
| Cloud network performance | Cloud provider and SD WAN configuration |
| Identifying origin of degradations | Any or multiple of the above |
| Monitoring visibility gaps | SD WAN provider, legacy APM/NPM tools |
With many domains and vendors accountable for potential SD WAN performance issues, an effective SD WAN migration plan needs to ensure that all domains are benchmarked, monitored and optimized at all stages of the SD WAN migration cycle.
Steps to a Seamless SD WAN Migration Plan
Testing SD WAN network performance and identifying bottlenecks at the pre-migration and trial phase is key to understanding what actions are required to mitigate performance issues with full scale SD WAN migration. This reference insight is also key to optimising application performance and digital experience consistent with user expectations. Here are the steps to follow for a seamless MPLS to SD WAN migration:
- Create a Performance Baseline for:
- existing MPLS, Ethernet and private connection network performance (latency, packet loss, path length)
- user digital experience for business-critical applications (private and SaaS)
- data center and public cloud connectivity.
- Test performance of ISPs, cloud networks and other connections (e.g. 4G/5G) that will form the SD WAN underlay and select them accordingly.
- Identify BGP, DNS and CASB latency (AS routing, geo-based DNS resolution performance, regional CASB proxy performance).
- Fine-tune SD WAN application routing and traffic prioritization using network path and digital experience monitoring.
- Resolve performance degradations originating from service providers with evidence-based collaboration.
- Measure performance vs. baselines: network connectivity and user application experience .
- Continuously monitor and optimize performance once migration is complete.
Benefits of a Seamless SD WAN Migration Plan
Following a proven, performance-centric approach to SD WAN deployment is essential to capturing the full value of the MPLS to SD WAN migration:
- Retire expensive MPLS links faster
- Select the most cost-effective, high-performance internet underlay providers
- Ensure consistent performance across all regions, sites, clouds and applications
- Embrace zero-trust networking and CASB security with the least latency overhead
- Exceed performance baselines and user expectations
- Deliver the best possible connectivity end-to-end, not just across the SD WAN
This article provides a guide to monitoring and optimizing network performance once SD WAN migration is complete.
Solutions for SD WAN Migration Monitoring
The transition to SD WAN usually follows a phased approach. Maintaining clear visibility across legacy networks while making the transition requires an SD WAN performance monitoring solution that not only measures the performance of SD WAN and internet-based networks, but also private connectivity and hybrid networks. To be an effective tool, SD WAN performance monitoring solutions should provide these capabilities:
- Internet, private, cloud and hybrid network performance
- SD WAN overlay and underlay performance:
- BGP route tracing and path changes
- Per-hop and per-provider latency, loss and congestion
- Latency introduced by DNS resolution, CASB security proxy location and configuration
- CDN and VPN network performance
- Digital experience of end users and how it’s impacted by network performance.
If you are planning–or are in the middle of–an SD WAN migration, you’ll quickly appreciate that complete visibility into this complex project is a wise, and cost-efficient way to assure a successful outcome. You can learn how to migrate and optimize SD WAN performance in more detail in this expert-led webinar:
* Sources : IDC 2020, NTT Global Services 2021, Telegeography, 2021, Zippia 2022, Coleman Parkes 2021, McKinsey 2021, Kadiska Monitoring of Top 3 Global Online Advertising Platform with 1.6B hits/day
