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Skype for Business Cloud PBX with PSTN Calling – 5 Steps to Success

We are all waiting with a mix of excitement and trepidation for when Microsoft reveal Cloud PBX generally available. It’s coming, December 1st 2015 will be key milestone date for everyone with an enterprise Office 365 tenant. We are about to experience probably the largest technology shift the IT world has seen since virtualisation became mainstream almost 10 years ago. Telephony has traditionally been an on-premises only solution from every vendor. There have been some attempts (even by Microsoft) to deliver a hosted telephony model in the past that have either failed miserably, or not scalable or reliable enough to support hundreds / thousands of endpoints.

However, all this is about to change as the Microsoft juggernaut is about to unleash it’s latest cutting edge solution – Cloud PBX. Leveraging the power of the infinitely scalable Office 365 platform and the additional horsepower Azure provides, there is absolutely no doubt Cloud PBX will be a massive success for Microsoft, but it will also signal a tectonic shift in the future direction of telephony. Competitors such as Cisco, Avaya, and Mitel to name a few will ultimately have to embrace this technology shift and acknowledge that a hosted PBX model is now the most viable and cost effective solution to deliver enterprise voice capabilities. Microsoft, have just been brave enough to do it first and hats off to them for taking the jump.

In the past, a hosted model hasn’t been the best model to adopt for telephony. The reasons for this were mainly down to scalability, consistency, reliability and of course quality. There was a significant lack of an end to end, single vendor solution that could guarantee all these requirements from the user’s desk to the PSTN over a hosted platform. Microsoft made the decision a few years ago to go cloud first and become less of a OS vendor and align more towards a IaaS and SaaS provider. The service subscription cost model means consistent and increased revenue and Microsoft use this for designing their cloud infrastructure and service offerings without the hindrance of customer on premises equipment or budget. This means Microsoft are able to develop and invest in new features and services rapidly which ensures they stay ahead of the curve. As a result, Office 365 has matured, services that were not possible in the cloud a year ago have now not only been made available, they have surpassed their on-premises equivalent making Office 365 the de-facto choice for many productivity work streams.

Microsoft realised, that in order to bring a viable telephony solution into the cloud, they needed to provide customers with the ability to guarantee quality of service to media traffic. The only way this can be achieved is to somehow connect the Office 365 cloud network to the customers. Therefore, Microsoft announced the provision of Azure Express Route for Office 365, which allows customers to connect their WAN to the Microsoft network using a low-latency, guaranteed network connection. Most of all this means that now customers and Microsoft can guarantee quality of service from the user’s desk to the PSTN. No other vendor can provide this at either scale or price.

Combining these services together, Azure, Office 365, Express Route and Cloud PBX, Microsoft have undoubtedly made a rainmaker no one can ignore now. The future of telephony is now a hosted model, making on-premises solution almost impossible to choose over it. Sure, there are many considerations, what about Contact Centers?, Desk phones? Video conferencing equipment? Well Microsoft and their partners have an answer to all these – it can / will be possible.

However, while all of this new “stuff” is exciting, many businesses will want to trial this service before committing their entire future direction towards Cloud PBX. Express Route, although highly recommended is not mandatory for Cloud PBX. Therefore, voice in the cloud (carefully not naming it Enterprise Voice) can be trialled relatively cheaply over standard internet connectivity. However, there are some steps you should take in order to at least give your trial the best possible shot at being a success regardless of your connection type.

Step 1 – Network Assessment and Bandwidth Calculation

Many businesses ignore the recommendations for a network assessment or bandwidth simulation and choose to adopt the “Ostrich” approach. Taking the attitude of “Yeah my network can cope” is a dangerous assumption to make. I have been to many deployments where customers have blamed Lync and Skype for Business for not delivering expectations and after investigation it has turned out to be environmental rather than an actual issue with Lync. Taking the assumption that things will be OK, often lead to increased expenditure in the future and a lot of pain along the way. 90% of the proof of concepts that fail can be attributed back to environmental restrictions or impairments. Very rarely do POCs fail due to lack of features.

Use the Skype for Business bandwidth calculator (https://www.microsoft.com/en-gb/download/details.aspx?id=19011) to make some simulations of expected consumption and it’s impacts on your network. This tool will give you a 35,000ft overview of potential problematic areas.

Identify these areas of concern, remediate these issues before the POC is started, or if budget is not available, mitigate these risks by either excluding network segments from participation or make allowances in your evaluation.

Step 2 – Quality of Service

Configure your internal network for QoS and apply QoS policies to your Skype for Business clients. Although, you cannot QoS over the internet, you can at least ensure the bottleneck is not going to be your internal network. Doing this now, means you can move from trial to production relatively quickly.

Step 3 – Provide the correct device

Many times I have walked into businesses where users are consuming enterprise voice functionality with £5 headsets they have bought off eBay and complain about media quality. I mean c’mmon, seriously? You expect this to be good and comparing it to that Cisco IP Phone you have on your desk is just not sensible. I cannot stress enough the importance of a good quality headset. I recommend and prefer Plantronics who have some awesome devices to meet even the most stringent of budgets. Profile your users, are they mobile? Are they information workers? Or are they executives? Each of these users will need specific devices to ensure they can complete their day to day work with least impact. Plantronics have an online profiling tool you can use to target these users with the correct device(s) http://pages.plantronics.com/ITDM-UC-Tool-Global-Landing-Pages_ITDM-UC-Tool-Global-EN.html Please invest in some supported and quality devices, they really do make a massive and positive impact to your trial. For more supported devices please visit https://catalog.lync.com

Step 4 – Prepare your network

Prepare your network for Skype for Business Online. Ensure you have all the required DNS and firewall rules in place, and also that you are not proxying this traffic through any web filters, caching servers, packet shapers or WAN accelerators. The connection between the client and the internet must be as clean as possible and with the least amount of network hops possible.

Step 5 – Test your Connection to Office 365

A key factor in your trial will be determining the baselines for your evaluation of the solution. There is no point basing your evaluation on best practices or perfect world scenarios. You need to set your expectations at what is feasibly possible to achieve in your environment. Being able to predict your experience to Skype for Business Online is extremely important. This determines whether Express Route requirements change from highly recommended to absolutely required. Ultimately, you aren’t going to know for sure what your experience is going to be like until you actually start producing traffic. However, you can at least perform a simple prediction on whether your connection will be suitable or not. To help you with this Microsoft have a cloud testing service called the Office 365 Fast Track Network Assessment Tool. This test your current connection to your Office 365 tenant and shows any potential issues with it. The service can be found here for EMEA: http://em1-fasttrack.cloudapp.net/o365nwtest (there are other URLs for APAC – http://ap1-fasttrack.cloudapp.net/and USA – http://na1-fasttrack.cloudapp.net/)

Using this tool you will need your tenant name <tenantname>.onmicrosoft.com

The tool will tell you if there are going to be any potential issues with your connection. As you can see from the below output, my home broadband would have some audio reliability issues

The tool also drills down into potential issues with your route to Office 365 and tests speed, packet loss, jitter, capacity, round trip time and latency

The tool finishes off with a report summary of all things good and bad

Using this tool you can take a very high level view on expected performance over the WAN connection, you can use this to then address these problems, work around them or account for them in your evaluation. Please note that this tool doesn’t not replace the need for any of the other steps to be omitted or disregarded.

Following these 5 steps can make the difference between a successful adoption of Cloud PBX or not. Cloud PBX may not be for everyone, but don’t let your network be the reason why!


  1. […] We are terndering for a new IP phone system. We stilll have a CENTREX analogue system here. Have had quote for NEC SL1100 and Mitel MiVoice Office 250. Als considering Polycom SIP handsets with Microsoft Cloud hosted PABX solution but UK this is a US only product due for UK release this year. May wait it out till then. But in the meantime do you rate either ofthese options. I like the Microsft hosted PABX more because its not locking you in to one handset manufacturer you can use any Lync / Skype for Business acredited handset or even any SIP handset with a reduced featureset AFAIK. Correct me if i'm wrong? Because we want to avoid vendor lock-in with Mitel I was thinking about using Microsoft Lync / Skype for Business. The main hardware vendor for Lync seems to be Polycom. Also Skype for Business integrates with Office 365 which we are signing up for in April. We are looking to use Office 354 cloud PBX possibly. Polycom VoIP Desk Phones for Skype for Business and Microsoft Lync – Products for Microsoft – Polycom, Inc. Office 365 / Skype for Business Online Solutions Not sure if a robust backup solution can be created with the above for times when our internet link goes down. Might we still require an onsite PBX with ISDN links? Looks like MS Cloud PBX is still US only but a UK rollout looks set for this year. Skype for Business Cloud PBX with PSTN Calling ? 5 Steps to Success | Mark Vale's Blog […]

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