When assessing an SD-WAN monitoring solution, it’s essential to take into account various factors. Among these, two crucial considerations should take precedence:
- Assessing the monitoring of end-user experiences.
- Implementing effective methods for identifying and resolving performance problems.
This priority arises from the fundamental nature of SD-WAN, which introduces an overlay path over the underlying physical network infrastructure (known as the underlay network). The introduction of abstraction and automation simplifies certain aspects but can also lead to increased complexity. In this article, we delve into some of the challenges associated with SD-WAN and explore how network monitoring can play a pivotal role in addressing them.
Path Remediation: Benefits and Challenges
One of the benefits of SD-WAN is path remediation and automatic failover. This feature concerns SD-WAN router that have multiple network connections, such as MPLS, broadband, or LTE. In this scenario, traffic can be routed through different lines, increasing reliability and quality.
For example, if a link is experiencing high latency or packet loss, the router may send the traffic through a different link. Some SD-WAN solutions even duplicate packets across two links, increasing the chances that traffic will reach the other end. These traffic changes may have an immediate positive impact but could negatively affect the end-to-end performance.
In fact, an SD-WAN router may route traffic across a link with lower speed, slowing down the connection. In the case of packet duplication, the overall bandwidth available to users is reduced. This is a similar case when you are stuck in traffic, and need to pick the lane that you think will get you faster to destination …
As a result, applications may perform slower than before the corrective action which causes users to complain. Troubleshooting these sorts of issues is very difficult without the right information.
SD-WAN Performance Testing
To overcome the obfuscation introduce by SD-WAN overlay network, it’s necessary to rethink SD-WAN performance testing. A performance network monitoring solution that runs end-to-end, synthetic network tests. It provide useful data to troubleshoot situations like the one illustrated earlier. At minimum, a network monitoring tool should collect the following metrics:
- Latency and packet loss to the remote application server (ICMP or TCP-based ping)
- Jitter for voice and video communications (UDP iperf)
- Number of network hops and path changes (traceroute or path analysis)
- Throughput to other WAN sites and to the Internet (iperf, NDT and speedtest)
SD-WAN solutions may report some of these metrics, but they’re either passive or only take into consideration a limited portion of the network. This typically is the last mile where the SD-WAN appliances operate.
A network monitoring tool for SD-WAN takes into account the whole end-to-end experience, from the user layer to the far end destination. Such a monitoring solution, relies on active network monitoring agents that are installed at the edge, either as a physical or a virtual appliance. The end-to-end network tests are run continuously, and results are retrieved in real-time and stored for historical review.
End-User Experience Monitoring
Monitoring the end-user experience is another key element of an SD-WAN monitoring solution. There are many ways to capture the end-user experience, and a variety of tools in the market that aim to do so. Typically, end-user experience monitoring includes application-layer statistics and metrics such as:
- DNS resolution time
- HTTP loading time
- Mean Opinion Score (MOS) for VoIP
- WiFi performance metrics
NetBeez provides a simple interface and plug-and-play deployment to monitor SD-WAN. If you want to test is, request a demo.
