Skype For Business 2016 client in UI Suppression mode

Introduction

I was tasked with creating a POC for a simple custom desktop video client that leverages the Skype desktop client to join a meeting. I am using an Office 365 E3 subscription with the latest 2016 Skype for Business client.

UI Suppression mode

For some good background on UI Suppression mode as it applied to Lync 2013 - see here  
Official documentation is here.
The Registry location for the UISuppressionMode flag for the latest client is HKEY_CURRENT_USER\SOFTWARE\Microsoft\Office\16.0\Lync\UISuppressionMode - I found this using the still awesome sysinternals process monitor tool

Skype for Business 2016 client SDK

It seems that Microsoft has not updated the documentation for the client SDK for the latest release. 
According to a few peoples experiences here and here the Lync 2013 SDK seems to work just fine.  
Beware though as this could mean it will be depreciated in the future.
Firstly you will need to install the Lync 2013 SDK. Essentially you need to download the SDK here and extract it using 7-zip (or whatever). Then install the msi for your platform.
Lastly you need to add the missing registry keys that the Lync 2013 SDK looks for to determine the client state :

HKCU\Software\Microsoft\Office\15.0\Lync

HKCU\SOFTWARE\Microsoft\Office\15.0\Lync\UISuppressionMode

Bugs and workarounds...

Never a dull moment, SO to the rescue - make sure to add a '?' to the end of the conf uri!

Remember you cant use the Automation object in UI Suppression mode, so you will have to modify some of the samples (and handle your own UI obviously).

UCMA 3.0 Advanced media woes

When it comes to conference management, im and presence, even basic media projects like ‘recording audio in wma format’ or even detecting tones then UCMA is definitely your friend – and I really love it. When it comes to doing advanced stuff related to audio and video, you have your work cut out.

Some recent requests I have had that are hard –

Detecting who is talking in a conference (like the way the icons show up against attendees in the Lync client – not to be confused with the active speaker) – that event only works when your using an audio recorder (because it comes from data in the RTP stream directly, so there needs to be media flowing). So the solution is to make a recording to a temporary file and throw away the file.

Oh and don’t even try and implement your own flow consumer class using the AudioVideoFlow provided because whilst many classes are public and it seems like it should work – under the hood it is specifically implemented for its own known types (Player, Recorder,SpeechRecognitionConnector,SpeechSynthesisConnector,ToneController).

Things like immersive collaboration are tricky when you can’t do stereo sound (let alone 3d sound) or any kind of video, in or out (you can pass it through using the back to back user agent, but that’s food for another post).   Resorting to the lower level bits  of the API just leaves SIP signaling – which is handy of course.

The only way to access the audio stream itself is to use the Speech connectors and they are hard wired to PCM @ 8k (tip SpeechRecognitionConnector.Start() returns a SpeechRecognitionStream which supports pretty much only the Read method  but still that’s often enough).

I like things this, a common feature in the AudioVideo namspace:

If you want to get fancy, and don’t need to stay in a supported configuration and don’t care if your code breaks after the next hotfix… you can use reflection to grab a reference to an active Microsoft.Rtc.Internal.Media.RtpMediaReceiver – notice that whilst its public and has some tasty methods and events – be careful it is in the .Internal. namespace for a reason, your not supposed to use it and its hidden behind internal and private members so you cant without reflection. – And just in case you didn’t read this right, DON’T DO IT THIS WAY (in production).

So I will get back to being busy writing my own managed media stack - contact me if you’re interested in using it in commercial projects.

Lync and ‘telephone-event’ in the sdp

An interesting little nugget in the nice new Lync client now it has the (love it or hate it) dial pad.

When an incoming SIP Invite sdp offer includes the ‘telephone-event/8000’ payload (also known as RFC 2833 out of band DTMF) the UI looks like this:

When it doesn’t, it looks like this:

Notice that the dial pad button has now disappeared.

Me, Myself and I

Cool – testing PIC making a call between Lync and Windows Live messenger on the same PC  with two webcam’s.

Lync reverse proxy using IIS ARR

Disclaimer : this is part of my Lab install series of posts, it works for me in my lab with a  small number of users but is neither a recommended or supported topology (AFAIK).
I have Lync standard edition server with mediation on the front end running in media bypass mode, Lync Edge server and Exchange server 2010 running on a single server with all roles.
I have decided to use IIS ARR + URL Rewrite as my reverse proxy for Exchange OWA, web services, etc and Lync reach client and web services all on my Lync Edge server. I did this because its already internet facing (and therefore ‘at risk’) and I figured its better to keep machines like this at a minimum. It is also the only machine not domain joined and has very few permissions on my network. Of course I could have setup ISA / TMG / whatever, but I want to focus on building software, not maintaining infrastructure.

1. Ensure IIS and .net are installed.
2. Download & Install ARR (includes rewrite).
3. Add a binding for your certificate (As this is on my edge server and I use the same certificate for both SIP and HTTPS I already have it installed on the machine)
4. Setup server farms for Exchange and Lync
1. 
2. (select advanced settings, choose ports 8080, 4443 – which point to the external bindings on the front end server))
3. (Choose Yes if you see this)
4. (double click routing rules)
5. (ensure URL rewrite is checked and optionally SSL offloading – depending on your bindings on the target server you may need this checked)
6. Repeat from step 4 for Exchange
7. Go to the URL rewrite configuration, either by clicking the link on the right pane on the routing rules screen in step 5 or on the main URL Rewrite icon under IIS when on the Features page for your server.
8. Modify the Lync rule as follows:
   
   Choose Using Regular Expressions and enter this expression :
   

   ((?:^dialin|^meet|^Fonts|^Abs|^CertProv|^ColabContent|^GroupExpansion|^LMStaticData|^MeetingContent|^MeetingFiles|^Reach|^RequestHandlerExt|^RgsClients|^WebTicket).*)

   
   
9. Same for Exchange with this expression :

   ((?:^owa|^OAB|^Microsoft-Server-ActiveSync|^EWS|^ecp|^Autodiscover).*) 

   Also select https protocol (depending on your bindings for exchange)
   
10. For completeness I have an OCS R2 CWA server in my Lync farm and have added a similar proxy for that too.

Now lets test

1. Go to https://yourdomain/owa
   
   
2. You should also run the tests here https://www.testexchangeconnectivity.com/
   
3. Go to https://yourdomain/meet
   (you can also create and join a meeting in outlook)
   
4. Go to https://yourdomain/reach/client/webpages/reachclient.aspx
   

Federating with everyone.

In order to use federation with OCS, OCS R2 and Lync you must obey this:

• The certificate must be issued by an approved public CA that supports subject alternative name. For details, see Microsoft Knowledge Base article 929395, "Unified Communications Certificate Partners for Exchange Server and for Communications Server," at http://go.microsoft.com/fwlink/?LinkId=202834.

This is a short list of official certificate providers :

Entrust
http://www.entrust.net/microsoft/ (http://www.entrust.net/microsoft/)

Comodo
http://www.comodo.com/msexchange (http://www.comodo.com/msexchange)

DigiCert
http://www.digicert.com/unified-communications-ssl-tls.htm (http://www.digicert.com/unified-communications-ssl-tls.htm)

Now in reality (and if you don’t need to be in a fully supported configuration) you just need a certificate that is issued back to a root certificate that you know everyone has. So assuming you might be federating with partners using OCS, OCS R2 or Lync Server 2010 we can assume their edge is running Windows 2003, Windows 2003 R2, Windows 2008 or Windows 2008 R2. So to narrow down your requirements you want a certificate that we know is installed by default on those platforms. In theory on Windows 2008 the root certificates are supposed to auto download on demand – however it seems OCS R2 doesn’t demand them, so they don’t get downloaded . Ok… so this is now quite a short (and getting shorter) list. So if you encounter weirdness that you can federate with some partners but not others then chances are that their certificate is issued by a root cert not installed in your system.

So as a certificate buyer, you really should buy a cert from an officially approved vendor. That said, after a bad experience with federation using GoDaddy certs, in my lab, I use (in an unsupported manner – as I use a single CN and don’t list any SAN’s) a RapidSSL cert from ServerTastic for $13.00 per year for a single domain cert – conveniently its issued from a root cert by GeoTrust / Equifax, which is far more prevalent than GoDaddy. I have had no issues since using this cert.

As a federating partner, if you want to expand your scope to ‘cheap’ federation partners, try installing the latest root certificate package here – after reading the warnings here .

Lync (and OCS) presence–the hard way!

So assuming that the easy way ( - the easy way is to use UCMA 3.0, see the ‘Microsoft UCMA 3.0\SDK\Core\Sample Applications\QuickStarts\PublishPresence’ sample in the SDK) is not for you for some reason – such as your implementing your own application using a 3rd party SIP stack on a non-windows platform and you don’t want to build a simple web service that does the heavy lifting for you on a windows box..
To get started you should read the dry but informative protocol spec, [MS-PRES]. And you should also review presence basics (that article is OCS, so doesn’t include the new Lync bits like location and pictures, but it’s a good overview). You will also find the Enhanced Presence Schema download handy – this consists of all the schema mentioned in the protocol specs so you can use a tool to create strongly typed objects in your language of choice as well as a help file (for windows) which is a little more digestible than [MS-PRES].