Lync Server 2010Comments (0)

Lync Server 2010 is real-time-communications platform from Microsoft. This is a successor to Microsofts Office Communications Server 2007 R2 but there is also a newer version called Lync Server 2013.

Lync Server 2010 comes in two editions; Standard Edition and Enterprise Edition.
The major difference is that Enterprise Edition are for larger organizations where you want to have High Availability, this is not something you would get with the Standard Edition of Lync Server 2010.

Besides the HA feature; both Editions support:
- IM and precense
- Conferencing
- A/V Conferencing
- Dial-in Conferencing
- Enterprise Voice
- Virtualization

New Server features
- Supports only 64-bit of Windows Server 2008 R2 and Windows Server 2008 SP2
- Many configuration settings were previously kept within AD, but are now stored in the Central MAnagement Store, except phone numers, sip addresses and so forth.
- Supports Powershell
- New GUI for administrators called Lync Server Control Panel
- New web-based client for users without an account or not having the Lync client installed
- Director is now a true server role
- For scalability and performace we can now separate the A/V Conferencing functionality into its own server role
- Mediation Server can now be collocated with a Front-End server

New Management and Administration Tools
- New Topology Builder that helps you create or edit the topology of the organization
- Central Management store that stores configuration data. All changes happends here and are replication to all other servers as a read only copy.
- Lync Server 2010 Management Shell
- Role-Based Access Control
- Web based management tools
- DNS load Balancing feature

New Client features
- Brand new interface
- Contacts tab are now enhanced
- Conversation tab
- Activity tab
- New way of displaying contacts by group, availability, level of privacy, with or without photos
- Privacy feature, control who can see your presence


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Lync Server 2010 installationComments (0)

This short little guide will give you a glimpse on how it is to install Lync Server 2010 as a standalone server!

First we want to use the rock solid Windows Server 2008 R2!

Pre-installation steps
1. Add RSAT Adds (AD DS and AD LDS Tools)
2. .NET Framework 3.5.1
3. Add IIS files easy using cmd

ServerManagerCmd.exe -Install Web-Server Web-Http-Redirect Web-Scripting-Tools Web-Windows-Auth Web-Client-Auth Web-Asp-Net Web-Log-Libraries Web-Http-Tracing Web-Basic-Auth

4. Microsoft Visual C++ 2008 Redistributable (you will be prompted to install this when setup starts)
5. Installation will now begin with the Core files

Deployment Wizard:
1. The deployment wizard should appear, in here we can Prepare AD, Install or Update Lync Server, Install Topology Builder
2. Choose Prepare first Standard Edition server
3. Install Topology Builder
4. Press Prepare Active Directory
5. Prepare Schema
6. Prepare Forest
7. Prepare Domain

Topology Builder:
1. New Topology
2. Name the file topology01.tbxml
3. Enter primary SIP domain: ‘’
4. Fill in Site Name: ‘HQ’
5. Fill in the Location information
6. New pool wizard appears
7. Fill in FQDN: ‘’ and choose Standard Edition
8. Choose features: Conferencing (without Dial-in, no PSTN), Enterprise Voice and Call Admission Control
9. Choose to collocate the Mediation Server
10. Leave archiving, monitoring or federating blank
11. No SQL server is specified, we use SQL Express
12. Define share ‘LyncShare’
13. Define external base URL
14. Wizard is now completed, choose to edit the topology and define the Central Management Server
15. Choose to publish the topology

1. Press Install or Update Lync Server system
2. Run Install Local Configuration Store (choose to retrieve information from the local store)
3. Run Setup or Remove Lync Server components
4. Install certificate, Send immediately or create offline request
5. Verify that the services are started
6. Create a SRV DNS record for the Lync Server,
6.1 Go to DNS Manager and expand Forwarding Lookup Zone
6.2 Click other new records and Service Location (SRV), and fill in:

Service: _sipinternaltls
Protocol: _tcp
Priority: 0
Weight: 0
Port Number: 5061
Host offering this service:

7. Start Server Lync Control Panel


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Error when publishing the topology in Lync Server 2010Comments (0)

Error message:
An error occurred: “Microsoft.Rtc.Management.Deployment.DeploymentException” “Cannot determine where to install database files because Windows Management Instrumentation on the database server is unavailable from your computer or user account. To continue, you can resolve this issue, or you can specify where you want to install the files.”

Solution: The pool name must match the FQDN of the server name itself!


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Media Bypass in Lync Server 2010Comments (0)

Normally when media is transmitted it would traverse in an Mediation Server.
In Lync Server 2010 there is a new feature called Media Bypass, which changes the path that the media would be transported. Instead of sending the media from a Lync client through a Mediation Server to the gateway, we could skip the Mediation Server and go straight to the gateway.

If Media Bypass is enabled we could:
- Improve voice quality by reducing latency
- Minimize the need of translation
- Minimize the possibility of packet loss
- Minimize the number of points of potential failure
- Improve scalability

As a general rule, enable media bypass wherever possible.


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How to estimate PSTN voice usage and traffic in Lync Server 2010!Comments (0)

Microsoft posted an article back in January 2011 with some thoughts on how to calculate the workload.

Light user
1 x PSTN call per user per hour – 15 users per port

Medium user
2 x PSTN call per user per hour – 10 users per port

Heavy user
3 x PSTN call per user per hour – 5 users per port

The following is an estimate of three different companies.

Company X with 500 light users:
500 users / 15 users per port = 34 ports

Company Y with 5,000 medium users:
5,000 users / 10 users per port = 500 ports

Company Z with 3,000 light users and 10,000 heavy users:
3,000 users / 10 users per port = 300 ports
10,000 users / 5 users per port = 2,000 ports
This would give around 2,300 ports


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A few words on Call Admission Control in Lync Server!Comments (0)

Call Admission Control or (CAC) for short is a feature in Lync Server 2010/2013 that determines whether there is sufficient network bandwidth to establish a real-time session of acceptable quality. CAC controls real-time traffic for audio and video, so if the default WAN path does not have the required bandwidth, CAC can try to route the call using an Internet path or the PSTN network.

If a new session of either voice of video exceeds the bandwidth limits that has been set on a WAN link, the session is either blocked or (for phone calls only) rerouted to the PSTN. The limits are defined in CAC polices which are enforced by the Bandwith Policy Service that is installed with every Front End pool.

If a call fails because of a CAC policy the rerouting of the call is used in the following order:
1. Internet
3. Voice mail

Call Admission Control can be used with a Mediation server regardless of whether it is connected to an IP/PBX, a PSTN gateway, or a SIP trunk.

The Mediation server is a Back-To-Back-User-Agent meaning its connected using two sides; one side with Lync Server and on the other side there is the gateway (PSTN gateways, IP/PBXs, or SIP trunks).
CAC can be enforced on both sides unless Media Bypass is enabled. If this would be the case, the media from the Lync client won’t flow through the Mediation Server, it would instead go directly to the gateway. This means that CAC is no longer needed.


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Understanding some telephony concepts within Lync ServerComments (0)

This guide will address the basics of PBX integration.
To have a better understanding of the various scenarios when it comes to PBX integration we can have a look at some basic telephony infrastructure.

Public Switched Telephone Network / PSTN
The PSTN is the the common network of telephony systems across the world. One could say its the Internet for phones, a cloud through which phone systems are connected.
Connections to the PSTN are analog phone lines, cellular connections or satellite based.

Private Branch Exchange / PBX
A PBX is a device that companies or organizations typically have on-premise which enables them to connect internal phones, fax machines or other devices together. Thx PBX allows for users within the organization to call each other without traversing the PSTN and incurring charges.
Like everything the the telephony evolved over the years and new types of PBXs emerged:
- Traditional PBX, does not have IP capabilites and has often very limited features.
- IP PBX, based on Voice over IP (VoIP), does not support analoge devices natively, all endpoints are IP based.
- Hybrid PBX – Like an old PBX but can be used with IP capabilites with expansion modules and software upgrades.

To be able to call each other, there must be some sort of information exchange between the PBX and the end users.
Such things can be phone numbers of the caller and the callee. This type of information is called signaling information.
Lets say we have a T1 connection with 24 channels. Each channel has about 64 kbps of bandwidth.
The first 23 channels carry the voice traffic, which means 23 simultaneous calls can be made. The last channel carries the signaling information for all of the first 23 channels.

Voice of IP / VoIP
As internal networks where growing the need for VoIP based PBX’s emerged. Instead of using analog lines one could now utilize the “computer network”. This allowed voice and datatraffic to share a common infrastructure with cuts down the cost significant.
The Session Initiation Protocol or SIP for short has emerged as a standard that many IP based PBS’s use for signaling and that is what Lync Server 2010 uses.

Although SIP meets the needs for signaling information, VoIP PBX’s still require a method of transmitting the media stream. The protocol used for this is the Real-Time Transport Protocol (RTP).
Encryption of the media traffic was also added later on and the Secure Real-Time Transport Protocol (SRTP) emerged which Lync Server 2010 uses by default.

Direct SIP
The most cost-effective way of integrating Lync Server into an existing PBX is if the PBX support SIP trunks.
In a Direct SIP scenario, the Mediation Server role serves as the conversation point between the two systems.
The signaling on both sides of the server is SIP but the Mediation roles translates the media stream between G.722 on the PBX side RTAudio on the Lync Server side.

Media Gateways
If Direct SIP is not supported, a third-party device called media gateway can be used to complete the integrations.
The media gateway helps translagte the traditional PBX protocols to SIP traffic, which Lync Server understands.
In addition one needs to configure the old PBX so it knows to route calls from specific extenstions to the media gateway which delivers the calls to the Lync Server.


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