Answers to your common questions from the SFB Broadcast Ep.43 on Hybrid PSTN

On May 26, 2017, Bill Verthein and Oliver Chiu sat down to present Skype for Business Hybrid PSTN.  During that live webcast, we had over 30 questions come in about Microsoft's Hybrid PSTN offering!  View that webcast here and see the answers to your questions about Hybrid PSTN from Bill below.

What is the YouTube channel we can watch this back on please?
http://aka.ms/sfbcastpast http://aka.ms/sfbcastpast

When do you expect that we can use local PSTN connectivity and numbers with service numbers?
We expect this before the end of this calendar year.*

Is there any plan to add automatic disaster recovery?
We plan to support full DR in the first half of 2018.*

Any improvements planned to make config file easy to edit? right now the TEXT file is error prone. Any error leads to script issues and needs CCE deployment to rerun.
Our CCE Appliance partners AudioCodes and Sonus have done a good job of making configuration a set of logical questions and preventing the chance of most conflicting answers.  

HA/DR capabilities for CCE? can it hit SLA targets?
Yes, CCE has HA/DR capabilities. We do not yet claim full DR capability (see the answer above) for CCE. However, we believe CCE in tandem with Skype for Business Online and Cloud PBX can satisfy our SLA obligations to our customers.  We measure and track this every day and have weekly reviews of our metrics in addition to assign product engineers to 24x7 on call support for customer issues.  

Hybrid PSTN is inherently harder to track down issues and understand root causes of issues because quality often depends on the quality of the customer's network as well as change control on their firewalls and network settings. To help improve resolving issues wherever the fault lies, we are currently and will continue to add improved diagnostics to help resolve problems to eliminate failures outside SFBO or CCE.

Will new tenant dial be supported on CCE?
Yes tenant dial plan is fully supported with Hybrid Voice options.

Is there any plan to add CAC capabilities for SfBO?
We do not have plans for CAC over the next 12 months. If this is a priority for you, please let us know.

Is tail end hop-off supported?
We currently do not support tail end hop off (we call that “destination based routing. This is planned in 2018.* Microsoft is uniquely positioned to drive this globally as we have the 2^nd largest global cloud in the world and we have more global fiber than any single carrier. Today our Skype Consumer product is the #1 international long distance provider in the world.

Can you route calls via different CCE appliances based on user DDI? E.g. London based DDI will break out via London CCE and Edinburgh DDI will break out via Edinburgh CCE?
We are planning improved routing rules coming to CCE toward the end of 2017.*  In the interim many customers do this call destination routing today with an intervening SBC.

Does CCE have the capability to support HA in two different DC?
Some customers have split an HA pool of CCEs across different data centers.  We recommend that each CCE be cross connected to every telco gateway in their site so the result of splitting a site across two DCs is you may have a lot of WAN traffic between data centers and that can impact cost.  When we improve our DR performance later this year you should see less need to split across DCs.

Do the local PSTN gateways have to be AudioCodes/Sonus or can they be existing Cisco gateways?
We support ANY SBC that interops with SFB mediation servers.  This includes Cisco and Avaya SBCs (as well as Acme).  There are a lot of smaller SBC companies that we don't test with that MAY also work as well. Usually all SBCs have well understood config profiles to interop with SFB20015 Mediation Servers (this is what CCE uses).

When CCE will support Media Bypass?

We are targeting this for mid-year 2017.* TAP has already begun.

What the requirements from the legacy PBX side? What is tried, tested and supported?
CCE will interoperate with any device that works with SFB2015 Mediation Server's SIP interface. There is a long list of partners that have submitted their equipment and officially certified interop.  Others have their own Skype for Business template for interop that they certify. Many other popular solutions have public discussions on how to configure those links (eg. Cisco's SBC has well known profiles that interop with SFB2015 Mediation Server).

Can one CCE box support multiple SIP trunks?
Yes, CCE can be connected to several SIP trunks. When our Media Bypass release is available, it will support up to 16 SIP trunks per CCE.

 When an online user at the internet external network dials a PSTN call, what is the voice codec you use between the online user client and CCE's edge? This is a media relay through mediation server...is it SILK codec (in this case, mediation do transcoding) or PSTN G711 codec ?

 To edge, we use G.711. In some cases we might initiate different codec. We will update our TechNet documentation shortly with describing the codec negotiation.

If we are using RCC today with a hybrid SFBOenviroment. can we use CCE to replace RCC?
CCE does not support RCC, but it does support SIP interop with legacy PBXs like Cisco and Avaya.  RCC was deprecated for SFB2015 (Call via Work was the recommended alternative) and RCC is not supported in CCE.

What are the Reverse Proxy requirements for meetings

All user with CCE are homed online and receive meeting services from Skype for Business Online. Therefore, there is no need for a local reverse proxy server

Is there any planned capabilities to selectively route traffic to PSTN to A) CCE and B) MSFT PSTN Calling Plans, for a given user? i.e. route traffic to an existing PBX (for coexistence purposes), but route to 'outside world' via PSTN Calling Plan.
There will be cloud based routing and dial plans for SFB Online where you can distinguish where to send certain destination phone numbers.

Once media bypass delivers, can users use SILK voice call from SFBO user until PSTN GW?
We are working on documenting codec negotiation and plan to update TechNet with detailed logic soon.

 Can a PSTN -> SfB conversation be elevated to a conference call?
Yes, but the call will transparently escalate to a cloud AVMCU (there is no audio mixer in the CCE).

 What is the expected RTO (Recovery time objective) for DR failover (Hybrid PSTN site policy change)?
Right now, customers must run recovery scripts to reassign users to a different surviving CCE site. Scripts moves approximately 3 users per second. This is expected to improve by early 2018.* 

Can we use PSTN Conferencing Number to land on on-premise PSTN and join the meeting hosted by users who are enabled on Office 365?

Our Cloud PBX team is currently testing this capability and we will have more to share later.  

Will dynamic E911 capabilities be introduced to SFBO at some point in time? And if yes, will that feature support Hybrid PSTN scenarios either with CCE or Cloud PBX with on-premises PSTN connectivity?
Currently, we only have Basic 911. By 1^st half of 2018* we will have enhanced call routing capabilities that will allow us to route on location of the user. The accuracy of E911 is highly dependent on what types of location data can feed our routing engine and ultimately the calls need to route to the appropriate carrier of record who has the legal obligation to provide 911 services. Even if we route to the right carrier for a user's current location the customer still has to have a proper 911 address set up for a given local phone # that would be used to proxy the userâ's phone number. We can't send a Chicago phone# to a Dallas PSAP when that Chicago user is at Dallas office. Expect this in 1^st half of 2018 as well.*

Can you confirm the license requirements for CCE - WInServ16 terms unlike 2012 indicate that everyone needs a Cal?
We have no current plans to move to WS2016 for the next few years. Our OS needs are generic and we mainly just require HyperV.  Our current WS2012r2 based CCE does NOT require per user licensing.

Will auto-update update my host? Is there any MP coming for CCE?
Not sure what MP is (Media Processor?), but yes AutoUpdate will update all the Operating Systems that need it, VM Guest OS as well as the Host OS.

CCE requires on-premises hardware. Is a hosted version of CCE planned and what's the timeline?
Well we are currently working on a significantly smaller footprint for Hybrid PSTN. In the interim we understand that some people just can't have on-premises hardware. For these cases, we can support private cloud deployments of stand-alone CCEs in a Hoster's Data Center that will VPN back to the customer's enterprise network.

First some background on why CCE is difficult to host. CCE has very intricate scripts that configure and update the SFB VMs. Most of our engineering effort for CCE has been in building the new script capabilities and evolving the older versions in the field. Because CCE needs to AutoUpdate, any 3^rd party Hoster modified scripts for hosting will either fail when the next AutoUpdate does its magic OR you can miss a required update for cloud interop. So there is NO Microsoft supported multitenant version of CCE.

Next, while running CCE in Azure seems like a no brainer, Azure is not optimized for bidirectional media like voice, so there are quality risks. There are additional limitations in the current way network interfaces are handled in Azure. Until the network virtualization and the bidirectional media performance issues are addressed we cannot endorse an Azure version of CCE at present.

From PBX integrations perspective can calls be routed via CCE to users who use PSTN Calling plan and Service Numbers such as Dial-in conferencing. This is to avoid call charges during coexistence phases.
Today SFB Hybrid PSTN (both CCE and on-premises Config Hybrid, aka Split Domain Hybrid PSTN) can coexist with cloud homed users who have Microsoft's PSTN plans. Hybrid PSTN and our PSTN calling can be arbitrarily assigned to all the online users in a tenant. All the users can call each other and can move between both methods of PSTN. All calls will be VoIP calls without going to PSTN network

*Disclaimer: Any date estimates may be changed substantially prior to final release of the solution. This only represents the current view of Microsoft Corporation at the date of the blog. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information presented after we publish this blog. Dates are for informational purposes only. Microsoft makes no warranties, expressed, implied, or statutory as to this information in this blog.