Tag Archives: Lync

Lync Server 2013 – Location Based Routing: Part II

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In part I Lync Server 2013 – Location Based Routing aka LBR, I discussed about the basic fundamentals, benefits, capabilities and routing methodologies. To extend the same, part II will cover implementation steps and test cases. As discussed in part I, LBR is a set of rules which handle your PSTN calls to comply with regulations of specific countries such as India. In telephony terms, it prevents toll bypass by blocking or modifying the routes of PSTN calls. Organizations can define the scope for LBR such as specific region, International calls, specific gateways or PBX and set of users. LBR policies can be based on user’s location or PSTN gateways location. LBR applies rules on different scenarios.

To test the LBR scenario, Single Site is deployed with asterisk PBX to generate voice calls. Test scenario will consider enterprise voice calls which are generated by Lync user located @ office and located @ home

Let’s start with deployment process:

1. Process start with Enterprise Voice deployment

Create dial plans and configure Normalization rules

Create and configure trunks, voice policies and define voice routes

2. Test Enterprise Voice setup

3. Create Network Region and Sites, define subnets based on your Lync infra.

4. Create Voice Routing Policy.

New-CsVoiceRoutingPolicy –Identity “Site1VoiceRoutingpolicy” –Name “Site1 Voice Routing Policy”

5. Set Voice Routing Policy and assign PSTN Usage (In lab scenario PSTN usage is created with name “Asterisk”)

Set-CsVoiceRoutingPolicy –Identity “Site1VoiceRoutingpolicy” –PSTNusages @{add=”Asterisk”}

6. Enable and configure location based routing and voice routing policy for Network Site

Set-CsNetworkSite –Identity Site1 –EnableLocationBasedRouting $true –VoiceRoutingPolicy “Site1 Voice Routing Policy”

7. Trunk configuration

Set-CsTrunkConfiguration –Identity Site1Trunk –EnableLocationRestrictions $true –NetworkSiteID “Site1”

8. Change Voice & Routing Configuration

Set-CsVoicePolicy “Site1VoicePolicy” –PreventPSTNTollBypass $true

Set-CsRoutingConfiguration –Enable locationbasedrouting $true

Follow the same steps for multiple sites carefully.

Test multiple calls scenario such as:

Incoming PSTN call while user @ his home location (Site1)

Outgoing PSTN call while user @ his home location (Site1)

Transfer and Forward while both the users @ their home location (Site1)

Simultaneous ring while both the users/endpoint @ their home location (Site1)

Lync users @ their home location are doing conference

Lync users @ their home location are doing Lync conference and PSTN user is joining conference using “Dial-in Conferencing”

Incoming PSTN call while user is logged in from outside

Outgoing PSTN call while user is logged in from outside

Transfer and Forward while both the users or one of them are not @ their home location (Site1)

Simultaneous ring while both the users/endpoint or one of them are not @ their home location (Site1)

Lync users @ their home location are doing conference and one of the conferencing user is trying to conference any PSTN user

These are few examples related to my Lab design, if you have more than one site then you need to test many other scenarios as well which certify that you are compliant with regulation.

Lync Server 2013 – Location Based Routing

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Location Based Routing is an impressive feature of Lync Server 2013 which distinct Lync Server 2013 from other UC solutions. LBR allows full fledge Lync 2013 Enterprise Voice deployment for those enterprises who are doing business in regulated countries such as India, UAE, Egypt etc. Lync enterprise voice deployment with LBR requires well-versed planning and designing as your one wrong step can disturb entire voice setup. Now, questions come to every Lync professional if LBR requires planning & designing; it means LBR is not enabled by default or in other ways, LBR configuration part comes later.

Question: If LBR is not enable by default and needs additional configuration, which methodology Lync Server uses by default?

Answer: LCR

Many Exchange professional who are reading this blog, can assume LCR means Local Continuous Replication which was introduced in Exchange Server 2007.

By default Lync server uses Least Cost Routing methodology. Least cost routing can reduce the call rates by minimizing toll charges and maximizing WAN uses, which can benefit to the enterprises but in another ways it is a revenue loss for PSTN service providers.

LBR Benefits:

  • Comply with regulations that restricts IP-to-PSTN routing in pre-defined cases.
  • Routes PSTN calls based on caller’s location to prevent toll bypass.
  • Scoped to specific locations, gateways, and users based on Network configuration.
  • Route call to the gateway closest to the calling party which increase QoS & QoE.
  • Minimize use of WAN which result in better QoS & QoE.

LBR Capabilities:

  • Route outgoing calls to a PSTN gateway local to the caller’s location.
  • Prevent incoming calls if the Lync client is not in the PSTN gateway’s location.
  • Route outgoing calls through international PSTN gateways when there is no local gateway.
  • Ensures that conferences do not have a mix of users from different locations and PSTN dial-out.

Outbound routing:

Trunk-to-trunk routing:

Inbound routing:


There are many test cases involve in LBR implementation which need to be tested. Implementation steps and test cases is explained in the next part of this article.

Courtesy: Lync Conference 2014.

A trusted server….. error while publishing Lync Server 2013 topology

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You may see “A trusted server….” error while publishing Lync Server 2013 topology.

In my case, I was adding Archiving and Monitoring role in existing Lync environment and had never faced this issue before.

After searching and looking into the error, I observed this error is occurring because of some existing entries in Active Directory.

To resolve this issue, I followed the below steps.

Note: Please take your AD backup before playing with ADSI Edit or ask your AD expert to perform the same activity.

  1. Open ADSI Edit (adsiedit.msc)
  2. Open Configuration partition and navigate to CN=Services>CN=RTC Service>CN=Trusted Services.

  1. Go to the properties of each entry under “CN=Trusted Services”.
  2. Type “msrtc” to search the Lync attributes in the property.

  1. Cross verify “TrustedServiceType” and “TrustedServerFQDN” with the error.
  2. Close the property and delete the entry.
  3. Publish the topology.
  4. If you get the same error again with different TrustedServiceType, follow the same procedure one more time.

Finally, publish the topology 🙂

Lync Server 2013 Brick Model

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Messaging is a business critical application for any enterprise. To increase the productivity, instant or real-time communication is very much required. Lync has become a more suitable option for business productivity which serves all real-time workloads such as IM/Presence, Audio/Video & Web conferencing, Group/Persistent Chat, Application & Desktop sharing and Enterprise Voice.

While enterprises are moving towards an application for real-time communication, services availability is concern for IT decision makers. To avoid complexities and provide more availability Microsoft came up with brick model architecture for Lync 2013. It allows scaling out your Lync FE servers from 1 to 12 and each server can support up to maximum 6666 concurrent users. Lync Server 2013 is loosely coupled with Lync Back End SQL server and use lazy writes feature to write data in SQL Back End server.

Lync Server 2013 divides users in a group and each group is dynamically assigned to three Front End Server, primary secondary and tertiary. Once user logs in, primary server serves the services and replicate the data across secondary and tertiary using synchronous replication as well as update the SQL backend server using asynchronous replication known as lazy writes. In case of primary server failure secondary server serves the services.

In Lync server 2013, Front End server keeps rtc, rtcdyn and xds database in local sql express store. To know more about Lync 2013 databases please go through Lync Server 2013 databases.

Now, we should talk about how brick model works. Basically, brick model is based on windows fabric and it consider nodes majority for availability. That’s why you need minimum three Front End servers to achieve high availability. The majority is considered when n/2 or n+1/2 Front End servers are alive.

For maintenance, you should restart/down one server at a time. If all Front End servers go down due to the power outage or any other reasons, please make sure you are starting all Front End servers at the same time.

Configure DHCP Server options for Lync Phones

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Setting up entire Lync Infrastructure is fun for Lync Professionals but real fun always come at last moment when end users start enjoying Lync services from their end user devices. To setup Lync soft client is quite easy while configure Lync phone devices are tricky one.

Trick comes with automate process of Lync phone devices which start from getting an IP address from DHCP server and end with user specific configuration such as selecting Time zone. Most of the companies use DHCP server to provide IP address to the client machine, simply Lync Phone devices can get an IP address from same DHCP server but it needs more to complete the entire configuration.

First of all, we have to understand any Lync client can only login if time is synchronized between Lync Server and Client. To meet this requirement starts with DHCP option 42.

If you have time server in your existing environment, specify the same in DHCP configuration option 42.

Let’s take an example if you don’t have time server in your existing environment then you can configure domain controller (PDC) as a time server.

  1. Create a record as shown below.

  1. Create service record as shown below.

Once you are done with this, specify same server address in DHCP option 004 & 042 and domain name in option 119.



Rest all the options you can see below need to be configured. But 🙂 you’ll not get any option with specific vendor by default in your DHCP server.

To make it simple MS provide dhcputil.exe in Microsoft Lync Server 2013 Front End / Standard Edition Servers.

 

Just copy this dhcputil.exe file in DHCP server and run below command

DHCPUtil.exe -SipServer <Lync Server Pool FQDN > -WebServer <Lync Server Internal Web FQDN> -RunConfigScript

In my case, I have copied dhcputil.exe in c drive of dhcp server.

C:\> DHCPUtil.exe -SipServer se01.insidemstech.com -WebServer sewebint.insidemstech.com –RunConfigScript

Once you will run the above cmdlet, it will add & configure all the required option as shown below

If you want to verify your dhcp configuration, run DHCPUtil.exe –EmulateClient from client computer.

If it doesn’t give any errors. It means you are done.

Now you can set pin for your Lync users and get logged in through Lync Phone Edition devices.

I hope it helped 🙂

 

How does Lync Federation work?

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Lync federation also known as external connectivity which allows a lync user to connect with users in other organization as well as public IM domains and XMPP. Lync support two kinds of federation open and close. When an organization allow open federation that means the organization has enabled automatic discovery while closed means the organization has disabled automatic discovery and added specific domain to allow federation.

Lync federation can be configured from Lync Control Panel as well as from Lync Management Shell.

It is time to know “how does lync federation work?” Let’s take an example of two organizations contoso.com and fabrikam.com. Both organizations have open federation.

Below is the step by step procedure:

  1. UserA (sipuri:usera@contoso.com) is looking for UserB (sipuri:userb@fabrikam.com)
  2. First of all it will check the access edge configuration for federated domain.
  3. As UserA request for sipuri: userb@fabrikam.com and in my case both domain is configured for open federation, the request will go to Access Edge Server and Access Edge Server will do lookup for domain name fabrikam.com.
  4. If fabrikam.com domain exists then it will look for the SRV record _sipfederationtls._tcp.fabrikam.com.
  5. Once it will get the destination address of fabrikam.com access edge server then it will try to establish the SIP/MTLS:5061 connection.
  6. Once Fabrikam.com will receive the request from contoso.com, fabrikam.com will check the access edge configuration to verify allow/block federated domains.
  7. Once the connection will be establish between both Lync Front End Pools / Lync Standard Edition Servers via Access Edge Server, UserA and UserB will talk to each other.

 

Note:

  1. All the required ports should be open in both ends.
  2. SRV record entry should exist in External Certificate.
  3. Federated domain should be allowed in both ends.
  4. XMPP doesn’t use SIP/MTLS:5061. It use XMPP/TCP:5269 to connect access edge server from public network and XMPP/MTLS:23456 to connect Front End Pool.

Step by Step Lync 2013 Edge Server

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Lync server consists of multiple roles and Edge server role is one of them. Lync server 2013 Edge server role take care of external connectivity of Lync users. It provides connectivity to Remote, PIC, Mobile, Federated and Anonymous users. Edge server deployment provides external access to different communication modalities IM & Presence, Web Conferencing and Audio/Video Conferencing.

Edge server deployment is not as simple as other Lync server roles and requires attentive preparation before jump into the installation. Let’s start the preparation for deploying standalone Edge server role.

IP Address Planning:

I am using 192.168.x.x/16 IP addressing for Internal Network, 172.25.x.x/16 IP addressing for Perimeter Network and 10.x.x.x/8 IP addressing for External Network. IP address on internal firewall is 172.25.33.100 which will act as a gateway for communication between perimeter network and internal network, IP address on External firewall is 10.1.1.100.

As internal NIC of Edge server is behind internal firewall and don’t have gateway in internal network address. So, we will have to route traffic from 172.25.33.10 to internal network via 172.25.33.100.

Follow below steps to add route.

Open command prompt with administrative rights on Edge Server.

Run “ipconfig /all” and note down the physical address and Ethernet adapter description of internal NIC.

 

Now run route print and note the Interface List ID of the internal NIC.

 

Now add the persistent route for internal traffic.

 

Open Lync Server Topology Builder on Lync Front-End / Standard Edition Server.

Right click on Edge Pool and select New Edge Pool.

 

Click on Next.

 

Write Edge Server FQDN.

 

Select appropriate features as per your requirements.

 

Select IP versions and NAT option according to your requirement.

 

Specify external FQDN and associated port numbers. (Note: If you have selected “Use a Single FQDN and IP address” then you will have to use different port numbers for all three FQDNs).

 

Specify the IP address for Edge server internal NIC.

 

Now specify the external IP address for all services.

 

Please specify the Public IP address which will be NAT to the A/V edge service. (In my case, the deployment has been done in LAB and don’t have public IP address. That’s why I am taking a different IP address.)

 

Define the next hop server. Next hop server will be your Lync pool if you don’t have director otherwise next hop will be your director pool.

 

Select pool and click on finish.

 

Now publish your topology.

 

 

 

Open Lync management shell with administrative privilege on Lync FE server and export the configuration.

 

Login to the Edge Server with administrative privilege and run Microsoft Lync Server 2013 setup and follow the steps.

 

 

 

 

After installing Lync 2013 core components, open Lync server 2013 deployment wizard.

 

Click on “Install or Update Lync Server System”.

 

Run “Install Local Configuration Store”

 

Browse Edge configuration file which you had exported in Lync FE server.

 

Click on Next.

 

 

 

Cross verify the installation through log file.

 

Now, Run “Setup or Remove Lync Server Components”.

 

 

 

 

 

Now, it’s time to request and assign certificates.

 

Follow the steps to request the Edge Internal Certificate.

 

 

 

 

 

 

Fill the appropriate information.

 

 

 

 

 

 

 

Now, request External Edge certificate.

 

 

 

 

 

 

 

 

(Note: If you want to use same public certificate for Reverse proxy also, add additional SAN’s for reverse proxy: lyncdiscover.domain.com, lyncwebservicesexternalname.domain.com, dailin.domain.com, meet.domain.com)

 

 

 

 

Once you have generated certificate request, can send these request to your certification authority to generate the certificates for you. As we are doing this setup in our lab, so we will use our internal AD CA.

Once you have generated the certificates open mmc and add certificates (Local Computer) via add/remove snap-in to import the generated certificates.

 

Import root CA onto Trusted Root Certification Authority.

 

Import generated certificates into Personal store.

 

 

 

 

 

Follow same step to import Edge Public cert also.

 

Now, It’s time to assign certificate to Edge services.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Once certification assignment is done, open Lync control panel in Lync FE server and go to Federation and External access.

 

Change External access policy as shown below.

 

Change Access Edge configuration policy as shown below.

 

Now everything has been done, it’s time to perform last step. Add Front End Pool / FE server entry into Edge server host file.

 

Finally, your external Lync clients will be able to login and you can use Edge services for external connectivity.

But, still you cannot use those services which require Reverse proxy. Therefore, configure your reverse proxy also to get all the things worked seamlessly.

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.

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.