Tag Archives: Unified Communication

Office Web Apps Server & Lync 2013

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Office Web Apps Server is required server role for Lync 2013 deployments. You can have too many questions in your mind regarding OWS for Lync 2013 such as what, why, how, where, when etc. To make it simple, I am creating flow which can help you to know more about Office Web Apps Server.

What is Office Web App Server? Office Web Apps Server is a new Office server product that delivers browser-based versions of Word, PowerPoint, Excel, and OneNote. A single Office Web Apps Server farm can support users who access Office files through SharePoint 2013, Lync Server 2013, Exchange Server 2013, shared folders, and websites. (Microsoft definition)

History? Don’t be confused between Office Web Apps in 2010 which was tightly integrated with SharePoint 2010 and Office Web App Server which is an independent office server product build by MS to support SharePoint, Exchange and Lync in advance fashion to provide rich experience to end users. Now, you can have a question in your mind about Windows Live Office Web Apps which is free for Windows Live and small-business users. Yes, you are absolutely correct but if you need these functionality on-premises, deploy Office Web Apps server.

Why do we need OWS in Lync 2013 deployment? Basically, Lync Server 2013 use OWS to handle PowerPoint presentations and improve the overall experience for presenters and attendees both. It provides rich presentation experience with high resolution and all new set of features which are available in PowerPoint such as transitions, animations and embedded videos etc. Lync 2013 supports standard DHTML with Java script which enable users to view presentation in mobile devices which doesn’t support Silverlight. Authorized/Privileged users can also scroll PowerPoint presentation as per their own wish without disturbing presenter.

How does it make difference? Lync server 2010 users (Lync Clients) were used to use PowerPoint viewer (which is based on PowerPoint 97-2003 and doesn’t support new features and other OS platforms except windows) and Lync web app users were used to customize DHTML with Silverlight which also doesn’t support all new features. Many mobile devices don’t support Silverlight which can’t be a part of PowerPoint broadcasts. To mitigate all these issues MS came up with Office Web Apps server which support all the features and provide rich experience to end users.

When should we deploy OWS? To make the things simpler you should deploy OWS before Installing Lync Server. You can also continue without deploying OWS server and use futuristic/planned FQDN of OWS in Lync topology builder. If you have existing OWS, you can use same for the Lync also.

Where should we deploy OWS? You should deploy OWS in your corporate network where you will deploy Lync Front End Servers.

How should we deploy OWS? OWS supports Windows Server 2008 R2 with SP1 and Windows Server 2012.

Prerequisite for Windows Server 2008 R2 with SP1:

  1. .NET Framework 4.5
  2. Windows PowerShell 3.0
  3. Platform update for Windows 7 SP1 and Windows Server 2008 R2 SP1 (KB2670838)
  4. Install Windows Features:

Import-Module ServerManager

Add-WindowsFeature Web-Server,Web-WebServer,Web-Common-Http,Web-Static-Content,Web-App-Dev,Web-Asp-Net,Web-Net-Ext,Web-ISAPI-Ext,Web-ISAPI-Filter,Web-Includes,Web-Security,Web-Windows-Auth,Web-Filtering,Web-Stat-Compression,Web-Dyn-Compression,Web-Mgmt-Console,Ink-Handwriting,IH-Ink-Support

  1. Restart the server

Prerequisite for Windows Server 2012:

  1. Install Windows Features:

Add-WindowsFeature Web-Server,Web-Mgmt-Tools,Web-Mgmt-Console,Web-WebServer,Web-Common-Http,Web-Default-Doc,Web-Static-Content,Web-Performance,Web-Stat-Compression,Web-Dyn-Compression,Web-Security,Web-Filtering,Web-Windows-Auth,Web-App-Dev,Web-Net-Ext45,Web-Asp-Net45,Web-ISAPI-Ext,Web-ISAPI-Filter,Web-Includes,InkandHandwritingServices,NET-Framework-Features,NET-Framework-Core –Source “D:\sources\sxs\”        (Note: Here D: indicates path of Windows Server 2012 Media)

  1. Restart the server

Install Office Web Apps Server. Click here to download

Install the Office Web Apps Server update KB2810007

Install Language Pack to support multiple languages. Click here to download

Configure Office Web Apps Server farm

Configure certificates, url etc.

Add more servers in OWS farm

Configure load balancing.

High Availability Options in OWS? You can deploy stand-alone Office Web Apps Server farm which supports all the features but doesn’t provide High Availability. If you need HA for OWS farm, deploy more than one OWS server and configure load balancing. Office Web Apps Server only supports Windows Network Load Balancing or Hardware Load Balancing.

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Autodiscovery and Lync 2013

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Autodiscover is an integrated part of Lync 2013 which was first introduced in Lync 2010 CU4. Basically, autodiscover was launched for Lync 2010 mobile client and then continued for all Lync 2013 clients. Lync 2013 Windows store app only connects through autodiscover service and does not rely on SRV & other A records.

Lync 2010 mobile clients had connectivity issues from internal network because most of the organizations use private CA for internal services and mobile client does not rely on that. To mitigate this problem, there were work around such as use public certificate for internal network also but this is not very easy because of different DNS names internally and externally or another way was redirect mobile clients to external DNS so that they can connect using public certificate.

You need to create lyncdisoverinternal.domain.com in internal DNS and lyncdiscover.domain.com in external DNS to get the Lync clients connected mainly Lync mobile clients and Lync 2013 Windows store app.

Once Lync 2013 windows clients try to login. The following process mechanism starts to connect to the Lync Server:

 

While Lync 2013 windows store app try only lyncdiscoverinternal.domain.com and lyncdiscover.domain.com to log in.

In other ways, we can say Lync 2013 mobile connectivity has been hoodwinked. Lync 2013 mobile clients are hard coded to look for a unique parameter which looks for external services to connect regardless of client network location. Lync 2013 mobile clients use Ucwa parameter for internal and external connectivity while Lync 2010 mobile clients use MCX web service parameter for the same.

Collocated or Stand-alone Mediation Server

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Most of the time, Lync Enterprise voice deployments need debate for collocated or stand-alone mediation server. Collocation of Mediation Server can reduce the TCO and data center footprints. Can Mediation server collocation be a wise option? To choose a wise option out of collocated or stand-alone mediation server depends on the following:

  1. Number of users enabled for UC-PSTN calls
  2. Number of UC-PSTN calls per user per hour
  3. Number of UC-PSTN calls at the time of peak load
  4. Connected gateway / SBC and mediation server
  5. Percentage of calls that support media bypass
  6. Branch sites configuration for UC-PSTN deployment

If I have missed any point here, please leave your comment so that I can add the same.

Any call which initiate from any Lync endpoint has two components signaling and media. For UC-PSTN calls, signaling always goes through Mediation server if stand-alone or Standard Edition / Front End server collocated with mediation server role.

No Media Bypass:

Media Bypass:


If your gateways, SBC or IP-PBX support media bypass, you can use collocated mediation server. But if you are planning for an option which do not support media bypass, I will advise you not to use collocated mediation server as collocated meditation server will increase load on front end servers which can cause of poor performance.

If you still want to use collocated meditation server, you can increase number of front end servers which can help you to distribute the load among front end servers.

A Stand-alone Mediation server deployment also depends on Branch sites which are connected to central site. If your branch sites don’t have dedicated PSTN connectivity then you should go with stand-alone mediation server pool. Again this topic requires more debate. As we know Lync 2013 use M:N trunk, in simple way it means if you have mediation server deployed in branch site and that can support media bypass you can still go with collocated option.

You can use Lync Planning tool to try all options and choose best out of that which provide you better ROI and best performance.

Lync 2013 Enterprise Edition Users and Servers Model

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Lync designing & planning is intricate part and right decision can help organization to get better ROI. This article may help Solution Architects, Consultants and System Administrator to choose best Lync server/pool model. Number of Lync servers in a pool, collocated or distributed model of Lync roles typically depends on No. of Lync users, their activities and different geo locations.

Lync 2013 Server Pools Number of Servers Supported No. of End users Remarks
Lync 2013 Front End pool (Collocated with A/V conferencing, Mediation Server, A/M server) 12 80,000 Max. Conferences size is limited to 250 users, Media Bypass is required to support all users with condition of 60 % users are enable for EV and only 40% calls are UC-PSTN calls.
Lync 2013 Front End Pool (A/V only) 2 Large conferences b/w 250 – 1000 users
Lync 2013 Mediation Pool 12 80,000 100% users are enabled for EV and 80% calls are UC-PSTN calls. 12 servers are required if Media by pass in not enable/supported for deployed EV connectivity. No. of servers will reduce based on Media bypass configuration according to the %.
Lync 2013 Persistent Chat 8 (4 active & 4 Passive) 80,000 1, 50,000 users can be enabled for pChat and 80,000 users can use concurrent. Only pChat pool can be stretched b/w sites to achieve DR. For more details check Lync 2013 HA
Lync 2013 Edge Server 4 – 8 80,000 Depends on how many users will access Lync services simultaneously, 3-4 servers for 30-40% & 7-8 servers for 100%
Lync Director (optional) 3 – 8 80,000 Depends on remote users, 3 servers for 30% remote users and 8 servers for 100% remote users.
SQL Server 2* 80,000 *2 for each backend databases

 

Important: Above data has provided for physical servers, minor change can happen if you use virtualization as per MS guidelines. It does not take any accountability of DR plan/scenarios. If you are planning for DR also, please account overhead of DR users if available.

Branch Site Connectivity options for Lync

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Good connectivity between sites is a basic requirement for every organization. To keep the same requirement in consideration Microsoft designed Lync with multiple branch connectivity options. Basically Lync 2013 supports four types of branch connectivity solutions to choose from which depends on your requirement. Branch sites can have few hundreds of users or few thousands of users. Therefore, solution also depends on usage, connectivity between the sites and number of users. Basically branch sites come into picture at the time of connectivity failure b/w central and branch site and provide resiliency to branch site users.

Only WAN connectivity: This solution is not called as a branch site connectivity option by Microsoft. Usually, it might be an option for small sites where organization has few users (1 – 25) but good WAN connectivity which can sustain the load of branch site users. Organization can have one or more sites which are directly connected to the central site with good WAN connectivity. All the users from this type of sites will directly login to central site and will use all the features including PSTN.

Survival Branch Appliance (SBA): SBA can have an option for those branch sites where organization has user’s b/w 25 to 1000 or maybe 2000 and don’t have local administrative support. SBA is an industry standard appliance which has Lync server registrar and mediation server component. SBA also contains PSTN Gateway for direct PSTN connectivity to branch sites. If you have users range b/w 25 to 1000 you can choose SBA accordingly or if you have more than 1000 users you can have two SBA, this is just an example but totally it depends on requirements and supported number of users by device. SBA provides resiliency to branch users at the time of WAN failure for Enterprise Voice but does not provide resiliency for other Lync features such as IM/Presence, conferencing etc.

Survival Branch Server (SBS): SBS can have an option for those branch sites where organization has more than 1000 users and have local administrative support. SBS is a Windows Server which has Lync server registrar and mediation server component installed on it. SBA does not contain PSTN Gateway for direct PSTN connectivity to branch sites. Therefore you need a separate PSTN gateway to connect PSTN service provider or you need SIP trunk connectivity with ITSP. Same like SBA, SBS provides resiliency to branch users at the time of WAN failure for Enterprise Voice but does not provide resiliency for other Lync features such as IM/Presence, conferencing etc.

Standard Edition Server: Standard Edition Server is an option to provide all the Lync functionality to branch site users or you can say that is a small central site. Standard Edition Server need a PSTN connectivity same as central site using a Media Gateway or SBC to connect ITSP/PSTN service provider. Standard Edition Server provides resiliency to branch users at the time of WAN failure for Enterprise Voice as well as for other Lync features such as IM/Presence, conferencing etc.

For qualified Lync infrastructure, please click here

High Availability in Lync 2013

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Availability is the concern for any enterprise application. In Lync 2013 Microsoft took a step ahead and delivered better availability options. Lync 2013 is a next level enterprise communication and voice based solution which based on different Lync Server roles. In Lync 2013 Microsoft did a tremendous job to consolidate many Lync roles and reduced the number of Lync roles and their complexity. To know more about Lync roles click here

Lync Server Standard Edition and HA*

This is big question for all to know about HA option in Lync Server 2013 Standard Edition. Lync Server 2013 supports up to 5000 users and can be deployed in a single box but to achieve more availability (*not exactly High Availability) you can deploy Lync 2013 SE in paired pool. Paired pools means deploy two Lync SE Server and paired them in a pool. Failover In a paired pool is manual activity (can be automated by PowerShell scripting) and users will get limited functionality at the time of failover. HA can’t be achieved for Persistent Chat in Standard Edition.

Lync Server Enterprise Edition and HA

Lync Server Front End (Audio/Video, Archiving & Monitoring is collocated): High availability can be achieved by deploying Lync 2013 Enterprise Edition Server pool. In one Lync Server 2013 EE pool you can accommodate 80,000 users by deploying maximum of 12 servers. Lync 2013 Enterprise Edition is designed by using brick model which works on Windows Fabric to provide HA. In Lync 2013 EE need minimum three FE servers (MS recommendation) for one pool. For availability, Lync Server pool needs N/2, N/2+1 server in a pool to work.

Microsoft recommends if you have large conferences for more than 250 users, a separate A/V (FE) pool can be deployed.

Lync Server Back End: Lync Server uses SQL server for its backend databases. You need databases for Lync Server backend, archiving/monitoring and persistent chat which can be collocated in one SQL server or deployed on separate (MS recommended) SQL Server instances. Lync Server 2013 supports SQL mirror for its databases. It does not support SQL failover clustering (not recommended) or SQL always on feature. To configure automatic failover in SQL server mirror, you need SQL witness server which can be SQL Express edition or SQL Server instance.

Lync Mediation Server: In Lync 2013, Mediation server role can be collocated with FE server role or can be deployed separately as a pool.

Lync Persistent Chat: In Lync 2013, Persistent Chat is a new server role which replace Lync server 2010 Group Chat server component which was not part of the Lync 2010 server roles. You can deploy Lync Server Persistent Chat as a pool to achieve HA and can have maximum 8 servers in a pool (4 active and 4 passive) for 80,000 concurrent users and total 1, 50,000 users.

Lync Edge Server: Lync Edge server role can be deployed as a pool in a perimeter network to provide HA for external (outside your organization firewall) users.

Director: In Lync 2013, Director is an optional role and can be deployed in the same way as Lync Server 2010 Director pool.

Reverse proxy: Reverse Proxy is not part of any Lync Server role but required for external users. You can use Microsoft Reverse proxy solutions such TMG 2010 / UAG 2010 / IIS ARR or can have any third party solution.

Lync Enterprise Voice Connectivity

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World is changing and moving towards rich collaboration and corporates can’t avoid these changes. As well as, we also can’t neglect our traditional way of communication. It means still we need phone to communicate with people. Microsoft did excellent job in this field as earlier only mailing solution was the key application for formal communication. But to understand better, we were using traditional phone. Microsoft Lync as an application can cater all your corporate needs. Microsoft Lync is a rich communication medium and easily can be integrated with other business applications such as Exchange & SharePoint.

Lync provides many options to enable Enterprise Voice. Usually organization uses traditional PBX or IP PBX which involves lots of cost and need distinct administration to manage the whole solution. Lync provides an Enterprise solution which can be deployed with or without your traditional PBX’s. In general there are three ways to enable enterprise voice with Lync.

1. Traditional PBX connectivity with Lync mediation server using media gateway.

2. Direct SIP, Advance IP PBX connectivity directly with Lync mediation server.

3. Direct SIP/PSTN Gateway/VOIP only deployment option directly with Lync mediation server.

4. SIP Trunk, Direct connectivity to Lync Mediation server from ITSP using SBC.