How to prepare for Microsoft's Lync-Skype integration

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Now that Microsoft owns both Skype and Lync, you'll need to be prepared for a few big changes, including the ability to make calls between the two. This news is especially good for businesses that want to simplify things for customers and partners, as it elminates the hassle of having to run two separate systems.

While it's true that you can already buy a Bing ad that allows people to click and call you directly for free via Skype, the Lync integration will offer so much more. If you have Lync, that's where you'll want your users to receive and make calls. It's also where you'll want to run meetings. Lync-Skype integration will let you include a button on your own Web page, allowing visitors to place a direct call to your business, which you can then answer in Lync.

You may have noticed that Microsoft has already rolled out basic Skype-Lync connectivity. This lets Skype users who sign in with a Microsoft account add Lync users to their address book, and vice versa. It offers chat and voice calls, plus presence updates. But, it's still limited in its capabilities. For example, you can't do video calls or group sessions, nor can you perform calls between Skype and Lync via mobile.

Speaking of mobile, the integration will support a wide range of mobile clients at launch. Microsoft is also building a new Skype cloud for the call setup and control features, along with a new gateway for signalling and call control.

Video calling between Lync and Skype

A bonus to Lync-Skype integration is that it offers improved voice quality, because Lync gets the Silk codec; the official line is that SILK is better than H.264 at capturing the sibilants at the top of the frequency range. This means you end up with richer, clearer and crisper voice calls. Your calls should go from sounding like bad FM radio to the smooth sounds of a CD.

Video calls will work when the full integration launches, using the H.264 codec. You can start with a video call or a voice call, and then add video. You'll also have the option to reject video for incoming calls if you only want voice. Voice, video and chat will also work on mobile, allowing you to make calls between Skype and Lync. This works with Office 365 and with on-premise Lync installations as well. And because Skype and Lync integration uses presence, Skype won't try to place a call to you if it sees that you're unavailable in Lync.

Calls will also be encrypted with TLS and sRTP, and Skype gets much better at NAT traversal, adding the STUN, TURN and ICE IETF standards; previously Skype used only some parts of STUN. As a result, it tended to show up in logs looking more like a hacking attempt than an enterprise voice client.

The Skype desktop clients for Windows and OS X will be available at GA; the Lync 2013 Cumulative Update 4 that adds the SILK codec is already up for grabs (older clients will use the G.722 codec). Microsoft is still looking into the possibilities for the Lync Mac client, which doesn't support H.264, but is currently marked as "potential future support.”

The Lync Web app didn't work with Skype in the first round of integration and it won't this time, either. But the Skype clients for iOS, Android, Windows Phone 8, Windows Store, Xbox and's will all support Lync connections. Likewise, Lync for iOS, Android, Windows Phone 8 and the Windows Store will support Skype connections in their next releases. If you use third-party tools, you'll have to check with your supplier, but the SILK SDK is available on a royalty-free licence.

There are still features that don't work between Skype and Lync right now, such as file- and screen-sharing, and multi-party calls. Additionally, Microsoft has yet to reveal what it might add in future.

Registering your domain for connectivity

If you use Office 365 or another Lync Online service, you can sit back and relax until launch. At that point you'll see a single slider for connectivity in the Lync Online admin panel under External Communications. This is where you can turn Skype integration on and off.

You can also change the External Communications settings for individual users. For small business tenants, the option is under Admin, Service Settings, Instant messaging, meetings and conferencing as External Communications; if it's on already, toggle it off and then back on to add Skype connectivity.

For Lync on premise, you'll want to be prepared in advance. As with public IM integration, you need to register your domain for connectivity here. Make sure you have your Microsoft agreement number, Access Edge service Fully Qualified Domain Name and SIP domain names (not including the FQDN) in hand.

The SLA says this can take up to 30 days, so you may want to get a head start. But if you're already configured to connect with Windows Messenger, AOL and Yahoo instant messaging using Public Instant Messaging Connectivity (PIC), then you're set for Skype-Lync connectivity. If this is the case, consider renaming the PIC provider to Skype, because the IM federation is going away. AOL and Yahoo IM connectivity will end on June 30, 2014, and Windows Messenger will be replaced by Skype. (If you have a hybrid Lync setup, make sure you enable on-premise connectivity before enabling it for Lync Online.)

If you haven't already set up your Lync edge server for public IM connectivity, you can do so in the Access Edge Configuration tab. You can find this in the Federation and External Access section of the Lync Server Control Panel; choose Enable federation and public IM connectivity. You may also need to enable external user access, which may involve topology changes or at least DNS and firewall port changes, and you'll need to create certificates to put on your edge servers. There's a planning guide here and a deployment guide here. But if you've already been through this process for external access and IM, you can skip this step.

Configuring your Lync setup for external access

Now it's time to configure your access policy. Start by creating one on the External Access Policy tab, found in the Federation and External Access section, to enable federated and public users. Decide whether or not you want additional policies to control IMs, archiving and partner discovery. As usual, you can set these policies for individual users or for groups, but Lync-Skype connectivity won't work until you create at least one.

Probably the most important policy to consider is whether to allow all incoming calls or if you only want to accept those from listed contacts, in order to avoid spam.

After this, you can configure the Lync client policy to show Skype as a PIC provider; you'll find the PowerShell commands here.

You'll also want to consult with different business teams to find out which policies will be useful for them. Notify users that they may start getting Skype calls and make sure they have the details to pass on to partners and customers. For example, you can only call from Skype to Lync if you sign in with a Microsoft account rather than a Skype account. You can find the instructions here.

You could also run training sessions on how to add Skype contacts to Lync clients, along with setting up alerts so that you can see when contacts are trying to add you. The Lync user will also have to add the Skype address to their favorites or contacts list, so the gateway can check their presence setting before attempting the call.

Unless you use Lync Online, enabling Skype to Lync calls involves quite a bit of work. But if you start planning now you can have it all set up by the time the new integration options go live.

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Mary Branscombe

has been a technology journalist for over two decades, and she’s been the formal or informal IT admin for most of the offices she’s worked in along the way. She was delighted to see the back of Netware 3.11, witnessed the AOL meltdown first-hand the first time around when she ran the AOL UK computing channel, and has been a freelance tech writer ever since. She's used every version of Windows (client and server) and Office released, and every smartphone too. Her favourite programming language is Prolog, giving her a soft spot for Desired State Configuration in PowerShell 4. And yes, she really does wear USB earrings. Find her on Twitter @marypcbuk.