Validating Unified Communications WAN / Wi-Fi Infrastructure

August 12, 2014 by Ixia Blog Team

When deploying a unified communications (UC) application like Avaya, Microsoft Lync, or Polycom in an existing network infrastructure, it is likely that you will have problems. The age-old question is, “Whose problem is it?” It could be your network, your systems, or in the UC application — or maybe a combination thereof. This has become a hot issue not just for enterprises, but for UC application vendors as well who must constantly defend their applications over an issue that may stem from an enterprise’s faulty network, a service provider’s low bandwidth, or a mobile device that isn’t UC-ready.

In fact, Microsoft selected Ixia to ensure Lync application reliability on mobile devices and as its official test house to qualify Lync applications against Wi-Fi networking devices. Armed with best practices from its engagements with Microsoft and its partners, Ixia is also helping enterprises validate their infrastructure to ensure the high QoE expected when using UC applications.

Ixia had a recent engagement where an enterprise needed a core network assessment and potentially, a redesign, to improve quality of experience (QoE) for its unified communications (UC). Ixia Professional Service (ProServe) did the assessment.

Upon first investigation of the network, it looked substantial enough to provide satisfactory QoE, but the Microsoft Lync UC system had never been reliable for the enterprise. Microsoft had been contacted many times to fix the issue, but insisted it was a network problem. The enterprise needed quantifiable data to show what the QoE was, from both a UC and an overall transport perspective, and where the problem was.

To assess the issues at hand, the ProServe team was asked to:

  • Validate the service provider service level agreement (SLA): perform core RFC-2544 Layer 2-3 backbone testing between two of the primary enterprise sites to ensure leased-line quality and bandwidth was as promised in the SLA
  • Assess the UC WAN: deploy probes to simulate real users and measure QoE/QoS

For the SLA validation testing, the ProServe team used Ixia’s IxNetwork L2-3 test solution to determine latency, throughput, and loss. The test results showed that the core network was adequate for transporting the UC system, so was not the cause of the UC problem. For good measure, the data was used to improve the network by optimizing routing.

For the UC WAN assessment, the ProServe team used IxChariot Pro (Hawkeye) for distributed active UC testing. To emulate end users, they strategically placed about 15 Ixia XR2000 assessment appliance hardware probes throughout the network. The placement strategy was intended to flush out changes in QoE due to a user’s physical or network location. For example, some were placed in remote offices, different floors of the buildings, various places with the network infrastructure, behind firewalls, etc.

The ProServe team followed 4 steps to effective UC WAN assessment:

  1. Discovery: determine how your users use Lync (or your particular UC), both on your network and as remote users
  2. Modeling: what is the best way to emulate traffic to reflect actual users based on application use, user location, time of day, day off week, etc.
  3. Traffic simulation: based on discovery and modeling processes, deploy probes, and generate traffic to validate network behavior
  4. Reporting and analysis: look at trends on latency, throughput, and loss, key for operational environments

Knowing that the network was in good shape from the IxNetwork testing, the ProServe team followed these steps to determine if the UC issues stemmed from the systems (routers, load balancers, etc.) or applications (Lync, other UC). Data from IxChariot endpoints deployed over Wi-Fi that generated Lync calls were consistently very poor quality and resulted in Lync not working properly. This was a defining moment in fixing the problem because they now had definitive data showing that Lync over the enterprise Wi-Fi did not work due to system issues.

Using diagnostics, the ProServe team was able to determine that, although the enterprise had set up traffic tags to prioritize real-time traffic as the highest priority, it wasn’t consistent across the network. With the data, the team narrowed it down to certain routers that were dropping traffic tags. Additionally, the Wi-Fi coverage was not acceptable for real-time communications and load balancing was not working properly.

To ensure UC delivers the experience users expect, Ixia ProServe unified communications experts are available to help:

  • Enterprises that are deploying or have deployed UC and not yet validated why your implementation is not working as it should
  • Device manufacturers that need to know their gear is UC-ready
  • UC application providers that need proof that a UC problem stems from a customer’s network or service provider