In our busy work world, it is important to stay in touch with your colleagues, customers, and others.  With Microsoft Lync 2010 for mobile devices, you can keep Lync in your pocket and stay connected no matter where you are.  Being ‘always on’ in Lync will be a new thing for most people.

After you sign into Lync on your mobile device, Lync Server keeps you signed in even when you are not using the app.  On Windows Phone, iPhone, and iPad, you will stay signed in forever as long as you use the app at least once every three days (or until you manually sign out).  On Android and Nokia (Symbian) phones, you will stay signed in as long as the app is running in the background.  Staying signed in allows you to receive IMs on your mobile device even when you aren’t actively using the app.

Presence Status with Lync for Mobile Devices

If you are signed in only on your mobile (and not on your PC), your presence status will be:

Status When…
Available (green) you are actively using the app
Inactive (yellow) the app is in the background
In a Call (red) you place a call-via-work call from Lync
In a Conference Call (red) you join an online meeting through Lync

Note that the mobile apps don’t publish calendar status, so your status will never be In a Meeting or Out of Office unless you are signed in from a PC. 

Having Lync on your mobile device creates a new situation for many people – being signed into Lync from two places at the same time.  (If you want to impress your techy friends, tell them you are MPOP’ed – having Multiple Points of Presence – now that you run both the new, cool mobile client and your PC client.  People stuck in the PC client-only world are SPOP’ed – with a Single Point of Presence.) 

A few things change when you are signed in from two Lync clients: 1) your presence status is an aggregation of the status from each device and 2) Lync handles invitations to IM conversations differently.  Let’s look at both of these.

Each Lync client publishes your automatic presence status to Lync Server.  When you are MPOP’ed, Lync Server uses the statuses to determine where you are most active. The status from your most active device is what other people see.  For example, you make a Lync call from your PC (In a Call), and your mobile phone is in your pocket (Inactive).  You are most active on the PC, so your presence is In a Call.  Or, you read IMs in Lync on your iPad at the bus stop (Available), and the PC in your office is locked but running (Away). You are most active on the iPad, so your presence is Available.

MPOP’ed presence will be new to people, but Microsoft designed the system to be very natural in representing your activity.  The choice of the most active status follows this pattern:
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One thing to keep in mind is that if you lock your PC but do not log off or shutdown, Lync is still running on the PC, and you are still MPOP’ed.

Of course, you can always override the automatic status and set your status explicitly.  Manual status (Busy, Do Not Disturb, and so on) always wins regardless of what you are doing on your devices. You can set a manual status in Lync mobile from the My Info screen.  Tap on your current presence and choose your new status.   You can also turn off a manual status by tapping Reset Status.

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IM Push Notifications

One of the great features of mobile Lync is that you can send and receive IMs from anywhere.  This has to work even if you aren’t using the app, of course.  On Android and Nokia (Symbian), Lync stays running in the background, so Lync Server communicates directly with the app. On Windows Phone, iPhone, and iPad, however, Lync doesn’t run when it’s not in the foreground.  On these platforms, Lync uses Push Notifications to send you messages. 

A Push Notification is a message that’s sent from Lync Server to the OS on your device, and the OS displays the message.  When you tap on the notification, Lync opens up the conversation and you start chatting.  If you don’t tap, the notification disappears after 10 seconds on Windows Phone and within a minute on iPhone and iPad. 

Automatically Accepting IM Invitations

When someone invites you to a new IM conversation, Lync on the PC pops up a “toast” in the corner of your computer screen.  If you don’t respond within 15 seconds, Lync automatically accepts the invitation for you and opens an IM window.  After auto-accepting, the PC client owns the conversation and all messages go directly there.  Shortly thereafter, Lync saves the messages to the Conversation History folder in Exchange, and you get an email with the missed conversation. You are sure to see the message eventually, either in the IM window or in email.

Problem: Lync on mobile can’t save messages to Exchange. Because of this limitation, the apps never auto-accept IM invitations.  Without the email backup, it might be days before you check Lync again and see the missed conversation.  For this reason, Lync will only consider a message “delivered” if the conversation was actually accepted by you on your mobile (or it was auto-accepted on the PC).  If the invitation wasn’t accepted anywhere, the sender gets an error that the IM was not delivered.

Lync Server will wait for one minute for an IM invitation to be accepted before Lync gives up waiting.  If you are SPOP’ed through the mobile client, you have that full minute to respond.  When you are MPOP’ed with both mobile and PC clients, however, the PC client will auto-accept after 15 seconds and owns the conversation.  On mobile, it is a race to see if you can respond, load the app, and respond before the PC grabs the conversation.

15 seconds is not much time when you think of all that has to happen:

  • Lync Server sends the IM message as a push notification
  • The message gets to the device and is displayed
  • You hear the notification and dig the phone out of your pocket or purse
  • You read and tap the notification
  • You type your PIN to unlock the device
  • Lync loads, connects to the server, and downloads data
  • Lync accepts the conversation

Whew!  It’s not uncommon to take longer than 15 seconds to get all of that done, especially if the push notification is slow getting to your device.  So what happens if the PC client grabs the conversation before the mobile client? On Windows Phone, Lync opens the IM screen and displays “Lync lost the connection to this conversation and can’t receive more messages until you send a reply”.  On iPhone and iPad, there won’t be a “Lync lost the conversation…” message in the IM window but you will see the first IM.  If this happens, all you need to do is send a message, and the mobile client “steals” the conversation from the PC client.

If you are a frequent user of the mobile apps, you may find this inconvenient enough to rethink leaving Lync running on their PC when you aren’t there.  Instead of locking the screen, sign out or shut down when you leave your PC. 

Push Notification Clearing House

Sending a push notification to you involves two Lync server components – the Lync 2010 Mobility Service (LMS) and the Push Notifications Clearing House (PNCH) – as well as the Microsoft Push Notification Service (MPNS) for Windows Phone or the Apple Push Notification Service (APNS) for iPhone or iPad.  Lync Server sends the IM message to LMS, which acts as the proxy for the mobile client.  LMS then sends the message to PNCH along with your mobile device’s MPNS or APNS address.  PNCH then sends the message to either MPNS or APNS, which delivers the message to your phone.

The PNCH server is part of Microsoft’s Office 365 server deployment, and it handles all push notifications for all Lync customers.  PNCH was designed to isolate on-premises deployments of Lync Server and LMS from direct communication with MPNS and APNS.  Because Lync uses a secure connection to MPNS and APNS, Microsoft can maintain the certificates needed to authenticate with MPNS and APNS on behalf of all on-premises Lync Servers. 

Phillip Garding
Senior Program Manager
Lync Team