Skype for Business Network Assessment and SOF Overview

The Microsoft Skype Operations Framework (SOF) provides a set of comprehensive & practical guidance  for customers to deploy Skype for Business Online with Office365. This framework was derived from traditional service management methodologies but built to specifically focs on Skype for Business Online. In the initial Plan phase of the SOF, there is a network essentials assessment which must be conducted to determine if the customer's network is able to meet the requirements for an optimal experience with Skype for Business Online. The Network Assessment involves several components including completing a questionnaire, creating the personas and calculating bandwidth requirements. This blog post will not cover all the components but focuses specifically on how to use the Network Assessment Tool that Microsoft recently updated to perform the necessary network tests to determine if the requirements are met and identify any potential network issues. The tool itself is free, easy to run and can be downloaded here https://www.microsoft.com/en-us/download/details.aspx?id=53885.

Before going deep dive into using the tool, its worthwhile reviewing the network requirements for an optimal Skype for Business Online experience. Microsoft has provided this in the website https://support.office.com/en-US/article/Media-Quality-and-Network-Connectivity-Performance-in-Skype-for-Business-Online-5fe3e01b-34cf-44e0-b897-b0b2a83f0917. The specific metrics that the network assessment tool measures include Latency, Packet Loss and Jitter and these are summarized in the diagram below:

All of the key metrics measure performance between 3 key networks: Client, Customer Edge and Microsoft Edge. Its important to understand that the "Edge" referred to here is not necessarily the Skype for Business Edge Server role. The Customer Edge actually refers to the network that sits in between the customer's client machine and the internet, typically this would be the home router or the corporate DMZ network. The Microsoft Edge refers to the entry point from the internet into the Microsoft Office365 network, which can be different locations depending of where the client machine is located at. This is illustrated in the diagram below:

Network Assessment Tool
Now that we've covered the fundamentals, we can deep dive into the Network Assessment Tool itself. First and foremost, the tool itself is based on the same Skype for Business client and media stack, does not require any installation and is a command line tool. The tool supports both TCP and UDP and utilizes the same ports and protocols as the Skype for Business client. It can be run on any client or server running Windows7 / WinServer2008R2 or later but it does require the VC++ redistributable package and you should ensure the appropriate package is installed for the machines that will be running this tool. The general recommendations for running this tool is as follows:

• The tool should be run at every location where Skype for Business will be used
• At each location, the tool should be run using a machine in the corp network as well as in the DMZ
• The tool should be run at representative times  for 1 hour, for eg: Monday 9-10am, Wednesday 12-1pm and Thursday 3-4pm, Friday 12-1am and Saturday 3-5pm Saturday
• Once initial testing has completed, there should be ongoing proactive tests such as running the tool every last Friday of the month for 30minutes

Before running the tool, we should configure the NetworkAssessmentTool.exe.config file and while there are many parameters that can be modified, we can simply use the default values provided and only really need to change the number of iterations as shown below:

The number of iterations for 1 hour of testing would be 180 as the tool is capable of making 3 iterations per minute. One parameter that is worthy of mention here is the "Relay.IP" value of 13.107.8.2. This is an Anycast IP address that will direct the call to the nearest Microsoft Edge network nearest to the location of the machine running the tool. Hence we need not change this parameter nor worry that we might be connecting to the wrong Office365 datacentre. Once we have the file updated, we can proceed to run the tool from the command line. In this test, I'm running the tool from a laptop connected to a 4G router, and therefore expect the results to be non-optimal as per the reqiurements. To save time, I've configured to only run for 10 iterations and the sample output looks as shown below.

When the iterations are completed, we can look at the results by running the cmdlet "ResultsAnalyzer.exe results.tsv" and it will provide a 90th percentile PASS/FAIL result for the key metrics as shown below: 

As expected, the results for "Skype for Business Client machine connecting to the Microsoft network edge" are not optimal and we see FAIL results for Jitter and Packer reorder ratio. Therefore we can conclude that this site will not be able to provide a high quality Skype for Business Online audio/video calling experience.

What about ExpressRoute?
When network performance is unable to meet the requirements for an optimal Skype for Business experience, one option may be to use ExpressRoute that may potentially improve the results, however this may not always be the case and its worthwhile to understand what exactly ExpressRoute offers in order to make the right decision. Firstly, ExpressRoute is a managed connection offered by qualified partners to connect the customer's Edge network to the Microsoft Edge network. It provides predictable performance, application of QoS and 99.9% availability SLA. ExpressRoute has 3 different peering modes as shown in the  diagram below:

Of the 3 peering modes, the one that impacts Skype for Business media quality and network performance would be "Microsoft Peering". Its important to note that even in the Microsoft peering mode, the customer's edge is still connecting to the Office365 public Edge network and not the Office365 backend servers. Of course Microsoft Edge networks are available in many parts of the world and customers would be peered to the nearest location to their office.  Before making the decision to use ExpressRoute, customers should perform the network assessment in all their locations and determine if the performance already meets the requirements for an optimal Skype for Business experience. If they do not meet the requirements, then ExpressRoute can be considered but only if it can improve the peformance in those specific scenrios. Otherwise customers should consider other alternatives services such as ISP direct peering to the Microsoft Edge. ExpressRoute is not the answer to all network problems, but it can certainly address requirements such as 99.9% SLA, QoS and gauranteed bandwith and managed connections.

Conclusion
The Skype Operations Framework is a critical element in any Skype for Business Online deployment. The Network Assessment tool is a vital component of SOF and customers should leverage this tool to measure network performance and address potential network issues that the tool uncovers.