One of the new features in Lync Server is the ability to use the Address Book Web Query (ABWQ) component in place of the default Address Book Service (ABS) for the standard Lync client.

By default only the Lync Phone Edition, Web App, and Mobile clients will leverage real-time web-query based searches against the Lync Server’s rtcab (or rtcab1) database which stores the same address book information that the ABS server files do.  In previous versions of Communications Server those databases existed only to service queries from clients which were incapable of downloading and storing local contact cache files.  Yet the standard Communicator client could only leverage the ABS download method and would not use the web query method for basic searching.

Now in Lync Server client policy settings can be used to modify that behavior of the standard Lync 2010 client software.  (The phone, mobile, and web app editions are still limited to using ABWQ only).

This TechNet article describes each client edition’s default behavior as well as introduces the Client Version policy setting used to control that behavior.  In order to use ABWQ only for all editions the client policy parameter AddressBookAvailability must be changed on either the default global policy or modified on a new policy which is then assigned to the desired users.

There are currently three available settings for this parameter which are self-explanatory based on the names: WebSearchAndFileDownload, WebSearchOnly, and FileDownloadOnly.

This article details the multiple steps to create a new policy, define that policy, and then assign it to a test user to validate the altered behavior.  If desired, this parameter can simply be changed on the Global policy to impact all users in the organization.

Validate Default Setting

Start by checking that the Lync Server environment is still set to the default behavior by identifying how many client policies are defined and then querying them for the address book policy.

• From the Lync Server Management Shell enter the following Get-CsClientPolicy cmdlet to list all defined client policies by name as well as list the current address book setting.

Get-CsClientPolicy | Select-Object Identity,AddressBookAvailability | ft

Only the default Global client policy was returned, indicating no other custom policies yet exist in this Lync deployment.  The default value of WebSearchAndFileDownload was also confirmed as the current AddressBookAvailability setting.

Force ABWQ

As previously mentioned the modified behavior will only be set for a single Lync user as a preliminary test by defining a new client policy and than granting that policy to the user.

• To create a new client policy using the default settings, yet modifying the client address book behavior, enter the following command in the Lync Server Management Shell using any desired string for the Identity value to set of the name of the new policy (e.g. ChicagoClientPolicy).
• Set the AddressBookAvailability parameter to WebSearchOnly.

New-CsClientPolicy -Identity ChicagoClientPolicy -AddressBookAvailability WebSearchOnly

• To assign the new policy to a single Lync user enter the following Grant-CsClientPolicy cmdlet.

Grant-CsClientPolicy -Identity jeff -PolicyName ChicagoClientPolicy

• (Optional) Verify the new policy and settings by using the following cmdlet to list all parameters of the new client policy.  Verify that the AddressBookAvailability parameter is set to WebSearchOnly.

Get-CsClientPolicy -Identity ChicagoClientPolicy

AddressBookAvailability                : WebSearchOnly

• (Optional) Alternatively the following cmdlet can be used to list only the non-null parameter values, which makes for an easier to read list of the current settings.

C:> (Get-CsClientPolicy -Identity ChicagoClientPolicy).psobject.properties |? {$_.value}| select name,value

Test Lync Client

Logon to a workstation using the account which was just updated to use the new client policy.  To visually verify that the ABWQ service will be used first delete the cached address book file (if this user has already signed-in to Lync once previously) on this workstation.

• On Windows Vista/7 workstations open the %userprofile%appdata
• On windows XP workstations open the
• Open the sip_username@domain.com folder for the user account which has been assigned the new client profile. (If it does not exist then skip the next step.)
• Delete the GALcontacts.db and GALcontacts.db.idx files.
• Leave the folder open and then sign in to the Lync client with that same user account.  Use the search bar as shown below to look for users not currently in stored in the contact list.  In the example shown the string ‘k’ was simply entered and results were listed below.  The folder view shows that no GALcontacts.db file was downloaded by the client, deducing that the Address Book Web Query method must have been used to return those results.

To further validate that assumption compare the IIS W3SVC logs on the Lync Server between a client still using the global client policy (which is using the ABS) and the newly configure client (which is using ABWQ).

• The current IIS log shows the following GET entry when a default client connection is established and the Address Book is retrieved or updated. (By default the Lync client can wait up to 60 minutes to download the address book but this workstation has been configured for immediate download using the process detailed in this previous article.)

GET /abs/handler/F-0e21.lsabs – 443 sip:Kristina@mslync.net 192.168.103.104 OC/4.0.7577.0+(Microsoft+Lync+2010) 200 0 0 47

• Yet the same logs shows no requests from jeff@mslync.net to download any .lsabs files. This also indicates that ABWQ is used by this client.

Additionally any search attempts on the ABS-enabled Lync client do not trigger any new POST or GET entries in the logs, while search entries from the ABWQ-enabled client do show a record of a WebTicket request against the Group Expansion service.  Each time a new search query was typed into the client another one of these POST lines would appear.

2010-11-27 15:43:40 192.168.103.23 POST /groupexpansion/service.svc/WebTicket_Bearer – 443 – 192.168.103.104 OC/4.0.7577.0+(Microsoft+Lync+2010) 200 0 0 47

Why Do This?

Now that we have seen how this is performed the question must be asked if and when it would be recommended to do this.  The entire point of the ABS method is to allow for local cache files to be used in an effort to reduce requests from clients to the Lync Server for a number of actions.  If comparing logs side-by-side it will be clear that the user photos are downloaded via the ABWQ regardless of the client behavior as these images are not stored in the GALcontacts.db.

One advantage to forcing ABWQ on all clients could be in an environment where changes to user attributes happen very often (multiple times per day).  The source address book files pulled from Lync clients are only updated every 24 hours by default, but those same changes in AD are pulled into the rtcab database roughly every 5 minutes by default.  Thus leveraging real-time lookups against the up-to-date database instead of cache-file based lookups could be more beneficial in some cases.

As with many new features that are added to later releases of software sometimes they can come from just a few large enterprises asking for a specific feature during trial use periods of pre-release code.  Meaning that just because the setting is there doesn’t mean you should rush out and turn it on.  In most cases the default setting is a default for a reason, yet if you understand what you are doing then having the ability to modify that behavior natively, and doing so in a supported fashion, is always a great advantage.