Mino – The UC Guy

Microsoft Unified Communications Blog

Posts Tagged ‘lync’

Lync Voice Deployment User Experience Comparison

Posted by Mino on November 11, 2010

During a very recent engagement with Microsoft Corp. competition team , they shared with me a new customer ready document for Lync voice deployments user experience comparison and I took the permission to share it on my blog.

There are three primary deployment scenarios for Microsoft® Lync™ Server 2010 customers. The three options, which differ in the user capabilities provided and the required infrastructure, are:

· Replace PBX phones with Lync to improve communications and collaboration, and to reduce infrastructure costs. This is the preferred Lync deployment scenario as it allows customers to simplify their communications infrastructure and rely exclusively on Lync Server 2010 for voice, conferencing, instant messaging and presence.

· Enhance PBX phones with the option to use Lync to improve communications and collaboration. This scenario is useful for organizations that are not yet ready to remove their existing PBX systems, but who want to provide their users either with the option to use Lync for phone calls instead of their PBX phone, or with the option to control their PBX phone with the Lync desktop client. The former approach is useful for providing seamless communications for employees working at home and on the road, and as a transitional approach while PBX systems are amortized and decommissioned. The latter approach is useful for providing desktop “Click-to-call” capability with existing PBX phones.

· Add instant messaging, presence, and conferencing to existing phone capabilities.This scenario is useful for customers that want to add Lync capabilities other than enterprise voice.





1. Entries marked “*” in the “Enhance, using Lync as phone” column apply when the user uses the Lync soft-phone only, not the PBX phone. Using the soft-phone in this scenario is the Lync default.

2. Entries marked “+” in the “Enhance, using Lync to control PBX phone” column apply when the user uses the Lync soft-phone only, not the PBX phone. Usng the soft-phone in this scenario requires that the user manually select “Lync call” in a drop-down menu each time a call is initiated.


As shown in the table above, with the Replace option, Lync is the only communications system used and provides the full set of unified communications capabilities to users inside and outside the office. With the Enhance option, users have both Lync and a PBX phone, and choose which phone to use at any given time. When Lync is chosen as the primary phone, as in the “Enhance, using Lync as phone” variant, users have the full set of unified communications capabilities inside and outside the office; when the PBX phone is chosen as the primary phone, as in the “Enhance using Lync to control the PBX phone” variant, users have a rich but reduced set of unified communications capabilities.


The Replace, Enhance, and Add options enable organizations to standardize on Lync as the only desktop software client for real time communications, but require different supporting infrastructure. In particular:

· The Replace option allows customers to eliminate separate PBX and conferencing systems and the associated user databases and management tools in favor of Lync Server, Active Directory, PowerShell, and Systems Center Operations Manager. This enables significant capital and operational cost savings, and takes advantage of existing skills in these areas.

· The Enhance and Add options require ongoing maintenance of existing PBX systems until those systems are retired. They also require the interconnection of the existing PBX systems with Lync Server, using Direct SIP or a third party gateway qualified via the Unified Communications Open Interoperability Program.This interconnection enables calls to be carried between Lync Server and the PBX systems.

The Enhance, using Lync to control the PBX phone additionally requires the deployment and maintenance of a connection to the PBX. This connection may require a PBX software upgrade and per user PBX software license fees, depending on the PBX manufacturer, and requires associated configuration and management.


The table below summarizes the key infrastructure differences for the deployment options.


As shown in the table above, the Replace option requires the minimum amount of infrastructure. This enables significant cost savings for organizations: for example, Sprint projects annual savings of over $9 million based on its replacement of nearly 500 PBX systems with Microsoft unified communications technology.

Posted in Lync 2010 Client, Lync Server 2010, Lync Telephony | Tagged: , , , , , , , , , | 1 Comment »

How to Enable HD Video for Lync 2010

Posted by Mino on October 28, 2010

Copied from the below Blog


One that might save a little bit of time for those folks wanting HD video for peer to peer calls between Lync clients…
You have to allow the maximum resolution to support HD 720p video – to do this you need a specific powershell cmdlet. Here’s how:

Set-CsMediaConfiguration -Identity:Global -MaxVideoRateAllowed HD720p15m

Restart the Lync Front End service and video calls can now utilise any 720p webcam that’s attached to the client.
So now you can see your colleague’s face in all its blemish free glory!

Posted in Lync 2010 Client, Lync Server 2010 | Tagged: | 6 Comments »

How to allow domain users to connect to Lync 2010 or OCS 2007 from Clients running on non-domain computers

Posted by Mino on September 15, 2010

I had a situation in our company where we have exceptional few users who got Domain credentials but they are working on Computers that are not joined to the domain.

However these computers run over the LAN or WAN, can communicate with the internal DNS and got the certificate chain of the CA imported to them and they use DOMAIN\UID and password credentials to login to mail , MOSS and everything is working fine.

When I installed the OCS 2007 R2 client on their machines and tried to login with the same behavior as mail using DOMAIN\UID , I was not able to log in and I received the below event log warning:

"Communicator was unable to authenticate because an authenticating authority was not reachable.”
The server may be asking for Kerberos authentication and Communicator is not able to find the Kerberos Domain Controller in order to generate credentials and authenticate.  The network administrator will need to change the configuration on the server to utilize only NTLM authentication before Communicator can login from this location properly, or connectivity will need to be made available to an authenticating authority"


also as for testing I removed the OCS 2007 R2 client and installed the new Lync RC client on the same machine , I know it is not supported scenario but I was just testing it. Now the user was able to login but it disconnects after 10 seconds then reconnects again , it keep in this loop. I also found the same warning in the event log.

I know why this is happening and I know it would have been solved from the beginning if i forced the OCS to use NTLM only rather than Kerberos but this was not something i can force.

So in the end the Solution was this problem was simple :

Ensure that the users when singing in to communicator 2007 or Lync 2010 to include the ".local" in the domain.local\username part of the authentication and not DOMAIN\username.

Posted in Common Errors, communicator client, Lync 2010 Client | Tagged: , , , | 3 Comments »

Microsoft Lync Server 2010 Media Bypass

Posted by Mino on September 14, 2010

What is it?
  • Media Bypass allows for Lync clients to communicate directly with a qualified PSTN voice gateway or qualified IP-PBX without traversing the Mediation server for media transcoding

  • When clients use Media Bypass, the Lync client uses the G.711 codec over SRTP

What are the benefits?
  • Greatly simplifies topology
    • Allows for Mediation server to collocate with Front End server or SBA because of low CPU intensity
    • Greatly reduces the amount of servers needed in deployment resulting in lower TCO
  • Optimizes media flow and quality
    • Eliminates unnecessary hops and potential points of failure
    • Saves WAN bandwidth
    • Improves voice quality with use of G.711 codec

However to enable Media Bypass ,you must ensure that either the Media Gateway ( SBA ) or the IP-PBX does support the Media Bypass feature.

Below are some different scenarios for the Media bypass between 2 sites:

First Scenario :

In this scenario the Client in the main data center dials a PSTN number, so the client communicates directly with the gateway using G.711 codec without the need to used the mediation for transcoding from RTaudio to G.711 Codec.


Second Scenario :

In this scenario the client is located in the branch site where there is no Lync Servers installed , when the client places a PSTN call it communicates directly with the IP-PBX over G.711 without the need for getting back to the Data Center pool mediation for transcoding. However this scenario is only applicable if your IP-PBX does support the new Media Bypass feature.


Third Scenario :

In this scenario we have two clients placing the call , one from the Data Center and the second is in Branch site. you will typically have this case in the international sites where you want to enable the least cost routing for international numbers. Lets say the Main Data Center is in US and the branch Site is in Egypt , and both Clients will dial the same number which is a US number.

So the first client who is in the US data center will communicate to the mediation server directly over G.711 , then the mediation will place the call through the Hosted SIP trunk to the PSTN also over G.711 since there is no local PBX available in the Data Center.

The Second Client who is in the Egypt branch site will dial the US number , the client will communication with the Mediation server place in the US Data center over RT Audio then the mediation will talk to the PSTN over G.711. In this second scenario we used RT Audio because it has got lots of features over the G.711 which consumes more bandwidth  , RT Audio gives much better quality over WAN due to correction mechanisms and the ability to overcome lost packets.


Forth Scenario :

In this scenario we have the same case like the last one , however we have also enabled Call Admission Control ( CAC ) which is a new great feature in Lync Server 2010. It allows call control over WAN to assure the accepted number of call over the allocated bandwidth and to refuse any extra calls over the allowed limit . What makes this CAC feature great also is not only to control calls over the WAN , but also to give alternate route for calls over the PSTN rather than using the WAN.

Ok let me explain it , the Client in the Egypt branch site is placing an international call to US number , so the client tries to place the call through the mediation placed in the US data center over the WAN , however due to WAN full usage and the CAC control ( call admission control ) so the call is not allowed to be placed over the WAN , however in spite of dropping the call we find that the client is redirected with alternate route to his local GW to place the call as international number from his PSTN gateway.


Fifth Scenario :

In this scenario the Client who is placed in the branch site places a call to a PBX legacy endpoint which is placed in the main site data center , this endpoint is connected to the IP PBX where this IP-PBX does not yet support direct Media bypass.

So the Client communicates over the WAN to the mediation server over RT Audio , then the call is routed after transcoding from the Mediation to the IP-PBX over G.711 , and finally the IP-PBX sends the call to the end point directly over G.711.


Posted in Lync 2010 Client | Tagged: , , , , , | 6 Comments »