Lync 2010 Media Bypass and CAC Part 3: Call Admission Control

In this post I will stay at the 100 level because I don’t think I could cover Call Admission Control (CAC) in just one post in any great depth. When you first look at the configuration for CAC it may start to get a little confusing. But the most important thing you can do with CAC is to plan, plan, plan. I could say it again but I think you get the message. Outlining your complete network is going to be critical to establish the correct admission control requirements. You will also need to either use a combination of the Control Panel with PowerShell or just use PowerShell to make a successful CAC configuration.

More about regions, sites and subnets with CAC

While my opening post helped open the conversation about Regions, Sites and subnets it was a high level view that wasn’t focused on CAC. Now we are here lets dive a little deeper in relation to CAC. For information from Technet on this topic see here.

Example diagram taken from Planning for Enterprise Voice In Microsoft Lync Server 2010


Network Regions – Network hub or backbone. Every network site must be associated with a network region. This concept seems a little odd when looking at the above diagram. Here is why. The sites drawn inside the circle are highly connected and CAC is not required. Those outside the green region circles require a bandwidth policy applied to their links although. This diagram is taken directly from the CAC planning guide and it really doesn’t explain that part. Just know that every site must be associated with a region and that remote sites like Portland in the example also require a bandwidth policy to enable CAC.

Central site – This is where you Lync pool resources are located and must be associated with a network region. Every network region is owned by a central site.

Network site – Can be a remote location, campus or a set of buildings. Basically it’s a set of IP subnets that have that are highly connected. In the example diagram Reno and New York are examples of a network sites. The difference between these two sites is New York is a highly connected site that does not require CAC policy applied to it. So if someone in Chicago is calling someone in New York there would be no restrictions. Reno on the other hand is bandwidth limited and does require the use of CAC. So if someone in Reno makes or received a call from any other sites in the North American region CAC would be applied.

Network Links - In the example there are a number of different link scenarios. They are Region to region (NA – EMEA), site to region (Portland –NA), site to site(inter-site) (Reno-Albuquerque). How you plan out your CAC requirements will largely come from your networking team who will have a vested interested in bandwidth usage. Not all sites require a bandwidth Policy applied directly to them. New York is a good example.

CAC planning

This is the most important stage in the process of deploying CAC. There is excellent guidance available in the Planning for Enterprise Voice Lync Server 2010 guide. So rather than belabor the point I will point to the guide on the best methods for planning.

How to configure CAC

This is a rough break down with the basic steps. As your network gets more complex as will your network mapping. First step is to enable CAC.


Figure 1 Enable CAC

Next, define a Central Site and associate it to a region. Central site is a site with Lync Server 2010 deployment or pool. In this case my central site is called home (my home lab).


Figure 2 Configure a region and central site


Figure 3 Define sites within region


Figure 4: Define a Bandwidth Policy


Figure 5 Define Links


Figure 6 Define Routes

Some network configuration tasks cannot be performed by using Lync Server Control Panel. For example, to create inter-site links, refer to the Lync Server 2010 Management Shell documentation for the New-CsNetworkIntersitePolicy.

The last screen shot is to highlight the ability to enable certain folks the ability to not be control by bandwidth restriction. This can be controlled through the voice policy so you can apply it to multiple users . See Jens blog for a more in-depth explanation of this feature


Benefits of CAC

Being able to define and control a roaming users use of WAN bandwidth is critical in some organizations. Unlike some systems that define CAC based on a single location for a device, Microsoft designed CAC with the roaming user in mind which is important as softphone technology becomes more prevalent.

  • No matter where a user is located CAC can be applied according to the sites policy without requiring any direct user or network configuration
  • Not only can you limit the number of audio and video calls you can also limit the amount of bandwidth those video or voice calls make per call
  • For calls that exceed the predefined max, they can be redirected to an alternate PSTN gateway or the internet if edge servers are in place.
  • Codec selection by the client can be maximized. The client will pick the codec that uses the least amount of bandwidth based on the max bandwidth allowed per call defined by the administrator. So potentially you could force all calls across a WAN link to default to G.722 if you set your max bandwidth per call below the threshold of RTAudio.

Points to keep in mind about CAC

1. The Mediation Server cannot enforce CAC when Media Bypass is in use which in any case the use of CAC should not be required.

2. CAC cannot be enforced on clients prior to Lync. So if you have Communicator 2007 R2 and lower registering to Lync Server during a migration period CAC will not work for those clients until they are migrated Lync.

3. Does not affect data. So this includes web conferencing and desktop sharing.

4. Better together with Quality of Service (QoS). You cannot achieve complete call quality relying solely on CAC. CAC is for bandwidth consumption control. It doesn’t not affect what happens on the wire. So if you configure CAC for a WAN link to a remote site other data can still affect your call quality over that link unless you deploy QoS. QoS is a big subject with a number of different ways to configure and maintain depending on your Enterprise QoS architecture. In saying that CAC is independent of QoS for the purposes of network configuration. Lync CAC does not require any specific network configuration nor is there any dependency on QoS.

5. Beware that if you are to deploy CAC anywhere in your network, all subnets need to be entered into Lync Server 2010. This is critical as the Bandwidth Policy Server coordinates bandwidth limitations based on your current location and not where you are homed which it cannot do unless you map your entire network. This sounds like a lot of work but it’s really not to bad as long you have a good list of where your subnets map to your network. Entering the subnets into Lync as a site will most likely be the easy bit. Gathering all the required network subnet information from your network will be the hard part. Hopefully you have a diligent network team that has documented all this information. If you have then its nothing more than transferring information to a csv file that can be uploaded via PowerShell script into Lync.

From the help file. How to assign subnets from a CSV file:

  1. Create a CSV file that includes all of the subnets you want to add. For example, create a file named subnet.csv with the following content:

IPAddress, mask, description, NetworkSiteID, 24, "NA:Subnet in Portland", Portland, 24, "NA:Subnet in Reno", Reno, 25, "EMEA:Subnet in Warsaw", Warsaw, 31, "EMEA:Subnet in Paris", Paris

  1. Start the Lync Server Management Shell: Click Start, click All Programs, click Microsoft Lync Server 2010, and then click Lync Server Management Shell.

Run the following cmdlet to import subnet.csv, and then store its contents in the Lync Server 2010 management store:


import-csv subnet.csv | foreach {New-CSNCSSubnet _.IPAddress -MaskBits $_.mask -Description $_.description -NetworkSiteID $_.NetworkSiteID}

Although this is not a complete guide to implementing CAC my hope was to cover the basics without having the need to read the planning guides before diving in.

Other posts in this series:

Regions, Sites and Subnets

Media Bypass

Comments welcomed.


Dialing Rule Optimizer on DR Rez

Its been an extremely busy few weeks and even though I am on vacation most this week I still managed to pump out a blog post,  just not on my own blog.

Thought I would give Ken the creator of the Dialing Rule Optimizer some free publicity. Check it out here.


Android for OCS 2007 R2

A third party developer has gone ahead and developed a Android client  for Office Communications Server called AndrOCS. Not to sure if its compatible with Lync but its currently in beta and downloadable from here. 



Just How Desperate are the Competitors to Learn about Lync?

Just when I thought the misinformation that competitors spreads about Lync/OCS was the tip of the iceberg to get a leg up in the UC race, they went a step further. Suspected full time employees of a competitor (who shall remain nameless, lets just call them vendor X) registered and attended Lync launch events by registering with false company names to get into invitation only customer events.

Now, I totally get the whole you do whatever you can to get a leg up on the competition type thing but this is a new low that I was unaware of. We have all done the thing at the trade shows where we watch a competitor do a demo of their product in an open and public forum. Maybe you went as far to turn your badge around or swapped badges to hide who you worked for, but actually submitting a false company name to get into an event,  really. Had it been an isolated case I probably wouldn’t have cared but it was by no means isolated to one city. The fact they think no one would notice is what really cracks me up. I am only aware of one large competitor doing this but time will tell. If you can’t guess who vendor X is yet your just not trying.

I am sure that vendor X would dispute this by saying it was the actions of “a few individuals” which it very well could have been but in the end Lync is a great product and it shows just how concerned “a few individuals” are.

Comments welcomed.


Polycom and Microsoft Moving Towards H.264 SVC

This is great interoperability news from two industry leaders. Looking forward to seeing what the outcome will be.

See Polycom’s announcement here.


Microsoft Kinect for Xbox 360 Versus Cisco Umi

If you haven’t seen any of the press releases this last week around Microsoft’s Xbox Kinect launch the rock you are living under must have its own postcode. Seriously. Although I haven’t received my Kinect yet (its in the mail) I am looking forward to testing out the new video chat feature with Live Messenger 2011. I am a part time gamer but I also use my Xbox 360 for Netflix. So having a Xbox live subscription is something I already have. If you buy from Amazon you can get a Live Gold subscription for about $40 a year.

So when video chat was announced it made perfect sense. The fact you can connect with Windows Live Messenger 2011 made even more sense still. There are also some other scenarios that make sense that I am sure will come to light in the coming months.


Kinect Video and Live Messenger 2011

I can’t say the same for Cisco’s Umi. Even though it may have the leg up around video resolution with 1080p, the price tag is the least compelling piece of the Umi story. At close to $600 for the unit itself and $25 paid to Cisco a month to participate, it just doesn’t make sense from a consumer point of view. The fact that I can buy an Xbox 360 250Gb bundled with a Kinect ($399 at Amazon) and a yearly Xbox subscription ($40 at Amazon) for less than the price of the Umi may make Umi a nonstarter.



Subscription Fee

Video Res

Who Can You Talk To?

Other uses

Cisco ūmi


$24.99 monthly subscription


Google Talk users


Microsoft Kinect for Xbox 360

$399.99 (Xbox 250 Gb + Kinect Bundle; $149.99 Kinect only)

Requires $49.99 per year Xbox LIVE Gold membership ($39 from Amazon)


Windows Live Messenger 2011

Gaming, Netflix streaming video, Messenger, ESPN

While Umi may be able to talk with Google Talk users I think the 330 million Windows Live users makes a much more compelling story. I was unable to find up to date numbers for Google which indicates to me that their overall market share is probably pretty low.

In the end, price and functionality are going to be the killer of Cisco Umi or any other at home Telepresence single function device for that matter. Video to other family members just isn’t that compelling from a consumer standpoint when there are free and low cost options such as Kinect, Live Messenger etc. Even the high end consumer is going to look pretty hard at what they are getting. I don’t think that there are that many reckless consumers in the market t that Umi is actually going to be around for very long in its current proposed format. Unless Cisco drastically change the startup or reoccurring cost I think their move into the consumer video market space is going to be a flop.

Video is certainly a big push at Cisco and for many companies video is seen as a cost saver and strategically important. But the consumer space is quite a different story with so many free options. The fact my Xbox will do video with Kinect is a bonus not something I specifically brought it for. Although I am excited about it, its not going to be the first thing I am going to try out. I think you get what I am talking about here.

In the end Kinect is just so much more compelling with sales expected to be in 2-5 million this Holiday season. Along with 40 million daily users of Windows Live and 34 million Xbox live subscribers there is already a large audience ready for Kinect Video. As for Umi, hmmm it does HD. Cool.

Comments welcomed.


Speaking 34 Languages Has Never Been so Easy

In an earlier post back in August I talked about a new SDK that will be released with Lync that allows the use of Bing Translator. Well after some more research I have actually found a second way to do a similar function. Although not as fancy as the extended window in Lync it still is a handy tool. Tbot is available to do translations if you have federated your Lync or OCS deployment with Live. All you need to do is add to your contacts and you can start translating. Tbot has been around for a while but its totally new to me.

Even though the screen shot below shows up as offline in Lync he can still IM translate 34 different languages. Once you invite is accepted he does show as online. You can also use Tbot with you Live account and after your invite is accepted he will show as online and you can begin use. As you can see below he has a set of commands you can see anytime by typing in Tbot.



Here are all the commands you can use with Tbot:
1 TBot lang - Show the current language pair
2 TBot change - Select translation languages
3 TBot stop - Stop translations
4 TBot start - Start translations again
5 TBot set - Set your preferred language
6 TBot detect - Detect the language of the text
7 TBot ? - Show this list of commands
See also: _

For more information about Tbot check out here.

Comments welcomed.