During the March 2013 patch tuesday, Microsoft released a patch (KB2760445) for Office Web Apps server 2013. The patch improves stability and performance and includes the latest fixes for known issues.

The Office Web Apps server role is used by Lync and Exchange to present Office Documents in a viewable format within client applications.

To prevent issues after updating, please follow this guide to update your Office Web Apps 2013 servers: http://technet.microsoft.com/en-us/library/jj966220.aspx

In short:

1. Download the update
2. Remove the Office Web Apps Farm: Remove-OfficeWebAppsMachine
3. Install the Update
4. Recreate the farm using New-OfficeWebAppsFarm with appropriate parameters like -internalURL and -externalURL

Make sure you recreate the new farm with the same parameters as the current farm.

Failing to follow these update steps may lead to a broken Office Web Apps server.  Note that this patch is also distributed through Windows Update and the above instructions still apply!

This year myself (Ruben Nauwelaers) and Johan Delimon presented a session around Lync 2013 on Techdays 2013. The session was recorded and now put online by Microsoft.

Title

Lync to the Future : Skype, Mobile, Meetings & Video

Abstract

Microsoft® Lync® 2013 is an enterprise-ready unified communications platform. Lync connects hundreds of millions of people everywhere thanks to the new mobile experience on tablets, smartphones and federation with partners, including Skype. Organize enriched virtual meeting experiences with HD Video Conferencing, Gallery view and high quality online meetings from web based clients. This session is packed with demo's Lyncing you to the future.

Watch/Download session video

Watch/Download slides on slideshare

Resources

Download Lync 2013 Trial

Get Lync Conference Sessions

Stay tuned for our member Michael Van Hoorenbeeck to post his recordings from Techdays

As part of the Technet Tuesdays, I'll be presenting 2 Lync Technet webcasts/livemeetings on April 9th. These are the abstracts::

AM: What’s new for Lync 2013 Clients & Devices

Microsoft® Lync® 2013 is an enterprise-ready unified communications platform. Lync connects hundreds of millions of people everywhere, on Windows 8 and other devices, as part of their everyday productivity experience.  Microsoft Lync 2013 has a redesigned user interface and important new features, Microsoft Lync 2013 delivers a familiar and engaging communications experience accessible across a variety of devices and platforms.   In this session we will focus primarily on the new client features.

Register Now

PM: What’s new in Lync Server 2013 : Persistent Chat

Microsoft Lync Server 2013 Persistent Chat Server enables you to participate in multiparty, topic-based conversations that persist over time.  The Lync 2013 client now integrates the features previously provided by Lync 2010 Group Chat client, a separate group chat client is no longer required.

Register Now

Lync Room System is a meeting room solution consisting of integrated hardware and software delivered by our partners and optimized to join Lync meetings. With Lync Room System you can join an online meeting with one touch and be ready to collaborate with remote attendees in seconds. It has all the equipment you need for great meetings:

1. High definition touch displays (1080p) for showing video and enabling collaboration. Lync Room Systems are available with 1 or 2 front of room touch displays depending on your room size
2. High definition video camera for capturing the room in full 1080p resolution
3. Wideband audio for clear sound from the room and to the room
4. Table-top touch meeting console to enable the meeting controller to manage the meeting without distracting the other attendees

It’s all brought together by the Lync Room System Edition software, which is a full Lync client optimized to bring the immersive meeting experience to a meeting room setting. It makes joining meetings as easy as on your PC and breaks down the barrier between in-room and remote attendees. Being able to see content and high definition video side by side makes remote collaboration more effective.

4 vendors have announced to develop and introduce LRS : Smart, Crestron, Lifesize, and Polycom

• Crestron and Lifesize plan to have their first LRS available in Q2 of this CY2013.
• Smart targets for Q3, while Polycom target 2H of CY2013 for first availability. 

Have a sneak preview at the following weblinks, including animations from Smart and Crestron :

• Smart : http://smarttech.com/Solutions/Visual+collaboration+solutions/Products/SMART+Room+System?utm_source=homepage&utm_medium=banner&utm_campaign=MicrosoftLync
• Crestron : http://www.crestron.com/rl/
• Lifesize : http://www.lifesize.com/en/products/video-conferencing-systems/lrs1000

More info
http://blogs.technet.com/b/lync/archive/2013/02/19/the-lync-room-system-lrs.aspx

Microsoft released Lync 2013 for the Android mobile operating system, completing the release of "2013" mobile clients across platforms.

**UPDATE**

Microsoft released two support articles regarding the Lync 2013 for Android client:

Normal 0 21 false false false NL-BE X-NONE X-NONE MicrosoftInternetExplorer4

Troubleshooting issues with Microsoft Lync 2013 for Android
Android smartphone devices that are supported for use with Lync 2013 for Android

From the Google Play store:

Lync 2013 for Android extends the power of Lync to your Android smartphone– including voice & video over wireless, rich presence, instant messaging, conferencing, and calling features from a single, easy-to-use interface.

Key Features:

- View colleagues’ availability in real time and select the best way to communicate – initiating an instant message (IM), email, voice or video call.

- Connect to Lync Meetings with a single touch, without requiring long numeric passcodes or conference numbers.

- Forward or simultaneously ring calls to your Enterprise Voice (Lync ID) number so you’ll never miss a call.

- Lync 2013 for Android provides transport layer security (TLS) and perimeter/internal network protection without requiring a VPN, so your communications experience is safer no matter where you are or what network you use.

Get Lync 2013 in the Google Play Store

 One of the new features in Exchange 2013 CU1 is support for creation and joining of Online Meetings in Outlook Web App (OWA).

Scheduling

Joining 

More info: Creating Online Meetings from Outlook Web App in Exchange 2013 CU1
http://blogs.technet.com/b/jenstr/archive/2013/04/02/creating-lync-online-meetings-from-outlook-web-app-in-exchange-2013-cu1.aspx?utm_source=dlvr.it&utm_medium=twitter

Today I presented 2 LiveMeetings regarding Lync 2013. I had a great time, lots of questions and hoped the attendees liked it as much as I did.

The PowerPoint presentations for both are now available for download:

• AM: Lync 2013 What's New In Clients and Devices
• PM: Lync 2013 Persistent Chat

Both sessions were recorded and Microsoft will put them online within approx. 1 week. 
Links will be announced on our website when available.

Microsoft released a new KB article regarding a hotfix for Lync Server 2013: KB2827772

Issue that this update fixes

This update fixes the issue that is described in the following Microsoft Knowledge Base (KB) article: 

• 2828162 Live Meeting 2007 client microphone remains muted in an audio conference

This hotfix should only applied on systems which are affected by this specific issue and is only available by contacting Microsoft Support

Lync User Management Tool (LUMT) enables administrators to manage contacts, ACEs and Privacy settings on behalf of Lync Server 2013 users.

With LUMT, it is possible to:
- Add contacts to default group or to a named group
- Remove contacts from the contact list
- Add ACEs to change the relationship level for the contacts in the contact list
- Remove ACEs for the contacts in the contact list
- Set privacy preference settings for the user to be either Private or Public (this corresponds to the settings in Options/Status in Lync client)
- Change alert notification settings for the user (this corresponds to the settings in Options/Alerts in Lync client)

Description

LUMT tool can be used to manage contacts, ACEs, privacy settings or alert notification settings for Lync Server 2013 users.

Important: The software and source code are provided as samples. They are licensed "as-is." You bear the risk of using it. The contributors give no express warranties, guarantees or conditions. See MS-PL license description for more details.

Usage

LUMT.exe /Mode:<LUMTMode> /UsersFile:<UsersFileName> [/ContactsFile:<ContactsFileName>] [/ContactsGroup:<ContactsGroupName>] [/ACLFile:<ACLFileName>] [/PrivacyPreference:<Privacy>] [/Delete]

Generic Parameter List

Download @ Codeples
http://lumt.codeplex.com/

For those of you who like a good book before bedtime, "Lync 2013 Unleashed" has been released and available through (by example) Amazon.com

The book is written by Alex Lewis, Tom Pacyk, David Ross and Randy Wintle, well known names in the Lync Technical community.

The abstract as on Amazon.com:

The most comprehensive, realistic, and useful guide to Microsoft Lync Server 2013, today’s leading Unified Communications system.

Four expert Lync consultants and implementers bring together in-the-trenches guidance for all facets of planning, integration, deployment, and administration. The authors introduce Microsoft Lync Server 2013, outline what it can do, and review the key improvements Microsoft has made in this version.

They cover every form of communication Lync Server can manage, including IP voice, instant messaging, audio/video conferencing, web conferencing, and more. You’ll find expert guidance on planning infrastructure, managing day-to-day operations, server roles, multi-platform clients, security, troubleshooting, and much more.

Microsoft Lync Server 2013 Unleashed contains a new section on Office 365 and Lync Online, a chapter covering coexistence between on-premise and Office 365 Lync deployments, and another introducing Lync online configuration and administration.

Throughout, the authors combine theory, step-by-step configuration instructions, and best practices from real enterprise environments. They identify common mistakes and present proven solutions and workarounds. Simply put, they tell you what works--and show how it’s done.

Detailed information on how to…
• Plan for any type of deployment, from simple to highly complex--including virtualized environments
• Walk step-by-step through installation, and understand important new changes in the installation process
• Overcome obstacles to successful migration from older versions of Lync or Microsoft Office Communications Server
• Manage server roles, including Front End, Edge, Monitoring, Archiving, and Director roles
• Efficiently administer Lync Server 2013 through the Lync Server Management Shell
• Leverage Lync Server 2013’s significantly improved capabilities as a PBX replacement and videoconferencing solution
• Integrate Lync with third-party video platforms, voice/video gateways, and cloud services
• Evaluate the option of providing Lync services through Microsoft Office 365 hosting
• Make the most of Lync Server 2013’s dramatically upgraded web, mobile, and desktop clients

When trying to Edit or Create a Persistent Chat Room in Lync  2013 you may encounter a problem opening the Persistent Chat Room management web site.

Error : “Server Could not process your request. Please try again later”

While this error does not give you a clear indication what is wrong we can check other things on the server.

• Check the Persistent Chat Server state
• Check the Application log for ASP.NET Errors
• Use OCSLogger.exe and find problems related to Persistent Chat

The state of the Persistent Chat service is normal

We find an ASP.NET error but without any clear indication what is wrong

Event code: 3005
Event message: An unhandled exception has occurred.
Event time: 4/17/2013 1:22:39 PM
Event time (UTC): 4/17/2013 11:22:39 AM
Event ID: d66e27a7a4ee4b81a7a95c97c3a48b92
Event sequence: 11
Event occurrence: 5
Event detail code: 0
 
Application information:
    Application domain: /LM/W3SVC/34578/ROOT/PersistentChat/RM/Handler-7-130106607609071496
    Trust level: Full
    Application Virtual Path: /PersistentChat/RM/Handler
    Application Path: C:\Program Files\Microsoft Lync Server 2013\Web Components\PersistentChat\Ext\RM\Handler\
    Machine name: SERVER
 
Process information:
    Process ID: 11644
    Process name: w3wp.exe
    Account name: NT AUTHORITY\NETWORK SERVICE
 
Exception information:
    Exception type: FailureResponseException
    Exception message: A 504 (Server time-out) response was received from the network and the operation failed. See the exception details for more information.
   at Microsoft.Rtc.Collaboration.PersistentChat.Internal.AsyncResultNoResult.EndInvoke(Int32 millisecondsTimeout)
   at Microsoft.Rtc.Collaboration.PersistentChat.Internal.MessageRouter.EndCommand(GenericAsyncResult`1 asyncCommand)

 
 
Request information:
    Request URL: https://externalurl.domain.com:4443/PersistentChat/RM/Handler/ManagementHandler.ashx
    Request path: /PersistentChat/RM/Handler/ManagementHandler.ashx
    User host address: 192.168.0.1
    User: user@domain.com
    Is authenticated: True
    Authentication Type: WebTicketAssertions
    Thread account name: NT AUTHORITY\NETWORK SERVICE
 
Thread information:
    Thread ID: 62
    Thread account name: NT AUTHORITY\NETWORK SERVICE
    Is impersonating: False
    Stack trace:    at Microsoft.Rtc.Collaboration.PersistentChat.Internal.AsyncResultNoResult.EndInvoke(Int32 millisecondsTimeout)
   at Microsoft.Rtc.Collaboration.PersistentChat.Internal.MessageRouter.EndCommand(GenericAsyncResult`1 asyncCommand)
 

Even using OCSLogger does not help us really

TL_INFO(TF_COMPONENT) [3]2D7C.10B4::04/17/2013-11:30:01.298.0000065d (ChatRoomManagement,Default.Page_Load:834.idx(63))(0000000000E11E04)Loading Room Management default page.
TL_INFO(TF_COMPONENT) [3]2D7C.10B4::04/17/2013-11:30:01.298.0000065e (ChatRoomManagement,Default.get_ValidRoomRequestFormat:834.idx(144))(0000000000E11E04)QueryString contains no 'id'.
TL_INFO(TF_COMPONENT) [3]2D7C.10B4::04/17/2013-11:30:01.298.0000065f (ChatRoomManagement,Default.get_ValidRoomRequestFormat:834.idx(144))(0000000000E11E04)QueryString contains no 'id'.
TL_INFO(TF_COMPONENT) [3]2D7C.10B4::04/17/2013-11:30:01.300.00000660 (ChatRoomManagement,Default.FoundClientSpecifiedLanguage:834.idx(336))(0000000000E11E04)Trying to find the resource for client requested language en-US
TL_INFO(TF_COMPONENT) [0]2D7C.10B4::04/17/2013-11:30:01.301.00000661 (ChatRoomManagement,Default.FoundClientSpecifiedLanguage:834.idx(343))(0000000000E11E04)Resource en-US matches the client requested language en-US
TL_INFO(TF_COMPONENT) [0]2D7C.10B4::04/17/2013-11:30:01.301.00000662 (ChatRoomManagement,Default.FoundClientSpecifiedLanguage:834.idx(336))(0000000000E11E04)Trying to find the resource for client requested language en-US
TL_INFO(TF_COMPONENT) [0]2D7C.10B4::04/17/2013-11:30:01.301.00000663 (ChatRoomManagement,Default.FoundClientSpecifiedLanguage:834.idx(343))(0000000000E11E04)Resource en-US matches the client requested language en-US
TL_INFO(TF_COMPONENT) [1]2D7C.3714::04/17/2013-11:30:09.764.00000664 (ChatRoomManagement,ManagementHandler.BeginProcessRequest:2092.idx(372))(0000000002F5F5AF)BeginProcessRequest: Trying to figure the exact request from client side
TL_INFO(TF_COMPONENT) [1]2D7C.3714::04/17/2013-11:30:09.764.00000665 (ChatRoomManagement,ManagementHandler.BeginProcessRequest:2092.idx(390))(0000000002F5F5AF)BeginProcessRequest: About to process landing page request.
TL_INFO(TF_COMPONENT) [1]2D7C.3714::04/17/2013-11:30:09.765.00000666 (ChatRoomManagement,ManagementBase.constructor:1199.idx(50))Trying to get the identity of the sip-authenticated user.
TL_INFO(TF_COMPONENT) [1]2D7C.3714::04/17/2013-11:30:09.767.00000667 (ChatRoomManagement,ManagementBase.GetNewConnection:1199.idx(84))(000000000218BE67)Primary home server: server.domain.com
TL_INFO(TF_COMPONENT) [1]2D7C.3714::04/17/2013-11:30:09.767.00000668 (ChatRoomManagement,ManagementBase.ConnectPersistentChatServer:1199.idx(178))(000000000218BE67)About to get provisioning data for userEndpoint
TL_INFO(TF_COMPONENT) [0]2D7C.3714::04/17/2013-11:30:09.824.00000669 (ChatRoomManagement,ManagementBase.ConnectPersistentChatServer:1199.idx(216))(000000000218BE67)About to establish Persistent chat endpoint to sip:GC-1-PersistentChatService-17@domain.be
TL_INFO(TF_COMPONENT) [2]3330.1B6C::04/17/2013-11:30:09.870.0000066a (ChatServer,UcmaTransport.HandleSignaling_SessionReceived:1732.idx(399))(0000000001A5B562)Session invite from <sip:server.domain.com:5041;grid>. Details=Federated: False, UserAgent: RTCC/5.0.0.0 rmweb/5.0.0.0, ClientVersion: 0.0.0.0/Current
TL_INFO(TF_COMPONENT) [1]3330.1B6C::04/17/2013-11:30:09.874.0000066b (ChatServer,ChannelServer.ShouldAcceptIncomingSession:663.idx(1379))(00000000012719D7)IncomingUser: <sip:user@domain.com:ebd59c1c-7f4c-4ac6-ae57-96bce934a6aa>, Federated: <False>, Result: <Allowed>, ActiveEndpoints: <4>, ActiveUsers: <3>, Principal: <[10]sip:user@domain.com> fetch took <00:00:00.0000573>.
TL_ERROR(TF_COMPONENT) [1]2D7C.3714::04/17/2013-11:30:10.058.0000066c (ChatRoomManagement,ManagementBase.ConnectPersistentChatServer:1199.idx(230))(000000000218BE67)Failed to establish Persistent chat endpoint to sip:GC-1-PersistentChatService-17@domain.be because of Command failed - see inner exception for details.
TL_ERROR(TF_COMPONENT) [1]2D7C.3714::04/17/2013-11:30:10.083.0000066d (ChatRoomManagement,ManagementHandler.BeginProcessRequest:2092.idx(555))(0000000002F5F5AF)Exception on BeginProcessRequest: Microsoft.Rtc.Collaboration.PersistentChat.CommandFailedException: Command failed - see inner exception for details. ---> Microsoft.Rtc.Signaling.FailureResponseException: A 504 (Server time-out) response was received from the network and the operation failed. See the exception details for more information.
   at Microsoft.Rtc.Collaboration.PersistentChat.Internal.AsyncResultNoResult.EndInvoke(Int32 millisecondsTimeout)
   at Microsoft.Rtc.Collaboration.PersistentChat.Internal.MessageRouter.EndCommand(GenericAsyncResult`1 asyncCommand)
   --- End of inner exception stack trace ---
   at Microsoft.Rtc.Collaboration.PersistentChat.Internal.AsyncResultNoResult.EndInvoke(Int32 millisecondsTimeout)
   at Microsoft.Rtc.Collaboration.PersistentChat.PersistentChatEndpoint.EndEstablish(IAsyncResult asyncResult)
   at Microsoft.Rtc.Internal.RMWebHandler.ManagementBase.ConnectPersistentChatServer(UserEndpoint userEndpoint)
   at Microsoft.Rtc.Internal.RMWebHandler.ManagementBase.GetNewConnection(CollaborationPlatform collabPlatform, String sSipUri)
   at Microsoft.Rtc.Internal.RMWebHandler.ManagementLanding..ctor(CollaborationPlatform collabPlatform, HttpContext cntx, String localRegistrarFqdn)
   at Microsoft.Rtc.Internal.RMWebHandler.ManagementHandler.BeginProcessRequest(HttpContext context, AsyncCallback cb, Object extraData)!

RESOLUTION:

While all of these logs and messages don’t say anything I decided to move my user which was currently hosted on the SBA in a branch office to the Front-End Server in the Datacenter and surprisingly this fixed the Persistent Chat Room website issues.
So I guess this must still be a big in Lync 2013

This cumulative update fixes the following issues:

• 2828830 Exchange UM-disabled user cannot check call logs on an Aries or Tanjay telephone that is running Lync Phone Edition

• 2829269 Message waiting indicator light on an Aries telephone that is running Lync Phone Edition doesn’t turn off after a user plays all unopened voice mail

• 2829272 "Music on hold" feature doesn't work for Lync Phone Edition for an Aries telephone when an audio file is configured

Microsoft Lync Phone Edition for Polycom CX500, Polycom CX600 and Polycom CX3000
http://www.microsoft.com/en-us/download/details.aspx?id=23866

Microsoft Lync Phone Edition for HP 4110 and HP 4120
http://www.microsoft.com/en-us/download/details.aspx?id=28158

Microsoft Lync Phone Edition for Aastra 6721ip and Aastra 6725ip
http://www.microsoft.com/en-us/download/details.aspx?id=18390

Microsoft Lync Phone Edition for Polycom CX700 and LG-Nortel IP Phone 8540
http://www.microsoft.com/en-us/download/details.aspx?id=21644

What's New For Lync 2013 Clients And Devices

About This Video

Microsoft® Lync® 2013 is an enterprise-ready unified communications platform. Lync connects hundreds of millions of people everywhere, on Windows 8 and other devices, as part of their everyday productivity experience. Microsoft Lync 2013 has a redesigned user interface and important new features, Microsoft Lync 2013 delivers a familiar and engaging communications experience accessible across a variety of devices and platforms. In this session we will focus primarily on the new client features.

Presented By: Ruben Nauwelaers

Download Slides

Watch/Download

What's New In Lync Server 2013 - Persistent Chat

About This Video

Microsoft Lync Server 2013 Persistent Chat Server enables you to participate in multiparty, topic-based conversations that persist over time. The Lync 2013 client now integrates the features previously provided by Lync 2010 Group Chat client, a separate group chat client is no longer required.

Presented By: Ruben Nauwelaers

Download Slides

Watch/Download

A Microsoft Excel spreadsheet that calculates WAN bandwidth requirements for a Lync Server deployment based on administrator-specified user profiles and network information, and a Word document user guide that accompanies the spreadsheet.

The new version allows you to select what client is being used.  It looks like there is still a lot of work to do to include other clients (listed in yellow and crossed)

Download:
http://www.microsoft.com/en-us/download/details.aspx?id=19011

I have added my Lync account to my favorites (I cannot find how to add lync accounts to the Skype mobile app but that probably requires the Desktop Client)

I can see the presence clearly in front of the name but the name somehow gets truncated first + last name without any spaces.

I can check the profile where it says Messenger/Microsoft Account which is not correct, this must be Lync Contact

Chat Works as expected

Calling from Lync to Skype on Windows Phone 8

Skype does not recognize the Lync sip address

But the call completes successfull

Dialing from the Skype mobile client on Windows Phone 8 works

Call completes successfull

Bring up the Chat and Profile tab works

The recent call list shows the outgoing call correctly but the incomming call as Unknown Number

Microsoft promised to bring the full Skype integration by june 2013, clearly everything is not functional yet but we are almost there.

Happy Skyping and Lyncing

Microsoft has released an update for Microsoft Lync 2013. This update provides the latest fixes for the 32-bit and 64-bit editions of Lync 2013. Additionally, this update contains stability and performance improvements. This update version is 15.0.4481.1004.

Note To determine the version of Lync 2013, follow these steps:

1. In Lync 2013, click the Options button.
2. Under the Help menu, click About Microsoft Lync.

This update also fixes the issues that were previously listed in the following Microsoft Knowledge Base article:

• 2760512 Description of the Lync 2013 updates: February 2013
• 2760556 Description of the Lync 2013 update 15.0.4481.1000: March 2013

Description of the Lync 2013 update 15.0.4481.1004: May 2013
http://support.microsoft.com/kb/2768004/en-us

Update for Microsoft Lync 2013 (KB2768004) 64-Bit Edition
http://www.microsoft.com/en-us/download/details.aspx?id=39009

Update for Microsoft Lync 2013 (KB2768004) 32-Bit Edition
http://www.microsoft.com/en-us/download/details.aspx?id=39008

Skype has added a quite nice feature where users can give their feedback for the quality of a call.

Now this would be so valuable during Lync Proof of Concepts, Pilots or even during full Lync deployments!

While Lync has very good monitoring of Quality of Experience, it is still computer generated and misses some real human stuff, the quality feedback can add that missing piece of information. 

Lync Online and Lync Server both support connectivity with Skype. This connectivity allows Lync and Skype users to communicate with each other, add each other as contacts, and see each others' presence. This guide for Lync Online administrators and Lync Server Administrators describes how to enable connectivity between Lync and Skype users.

Provisioning Guide for Lync-Skype Connectivity
http://www.microsoft.com/en-us/download/details.aspx?id=39071

Configuration change for Lync 2013

Remove-CsPublicProvider -Identity Messenger
New-CsPublicProvider -Identity Skype -ProxyFqdn federation.messenger.msn.com -IconUrl "https://images.edge.messenger.live.com/Messenger_16x16.png" -VerificationLevel 2 -Enabled 1

This post is an update to the following article:

Download Provisioning Guide for Lync-Skype Connectivity
http://www.pro-lync.be/blogs/lync2013/archive/2013/05/31/download-provisioning-guide-for-lync-skype-connectivity.aspx

2) Signaling

If signaling is not working between Skype & Lync you probably need to update your EDGE Servers certificate for the GTE CyberTrust Global Root and the Baltimore CyberTrust Root

Lync Mobile Push Notifications
http://blogs.technet.com/b/lync/archive/2013/05/02/lync-mobile-push-notifications.aspx

Lync Server Federation with Microsoft.com: Root Certificate Change
http://blogs.technet.com/b/nexthop/archive/2013/05/09/lync-server-federation-with-microsoft-com-root-certificate-change.aspx

1) Media

When you follow the Skype Provisioning Guide you have enabled federation between Skype & Lync but you have not configured the media (audio).  Lync & Skype will do the signaling fine but trying to accept the call then the media channel never establishes and you get an error. 
If you never federated with MSN Messenger and you have to do configuration from scratch then you need to run an extra commandlet to enable media to work between Lync & Skype.

The problem is that by default Lync Requires Encryption by default for all media calls en like “MSN”, Skype does not support encryption.
To turn off the requirement for encryption you can do that with the following command:

Set-CsMediaConfiguration -EncryptionLevel SupportEncryption

Running this command does not disable encryption for Lync calls but when encryption is not available it will fall back to unencrypted media traffic like Skype calls  (Encryption is still used when both parties support encryption)