As briefly mentioned in a previous blog article the latest RMX software release now supports the ability to directly register and advertise presence for a Virtual Meeting Room (VMR).  Previously calls from Lync clients to VMRs would be placed to a SIP URI that displayed Presence Unknown, which could seem like an odd scenario for users expecting to see some type of presence before placing calls to a user or contact.

Prerequisites

Before enabling SIP registration and presence for any Virtual Meeting Room on the RMX conferencing bridge the standard OCS/Lync integration steps must first be completed.  The latest UC Deployment Guide covers this configuration in detail.  It includes creating an SSL certificate for the RMX that is trusted by the Lync server, configuring the RMX with the proper SIP settings, and then adding routes and an application pool in Lync for the RMX.

Once video calls are working from Lync to the RMX utilizing the static routing configuration then these additional steps can be completed to setup direct registration of specific virtual meeting room on the RMX.

The only requirements within Lync are that a dedicated user account is created in Active Directory and then SIP-enabled in Lync.  If external or federated Microsoft SIP users should be allowed to call the virtual meeting room then the account needs to have the External Access policy configured to allow Federated and/or External Access as well, but this is not required for internal use only.

The password value and policy is also not important as the RMX does not utilize the individual passwords of each AD user account during registration.  By leveraging the Trusted Application configuration detailed in the deployment guide the RMX is able register as any existing Lync user without that account’s individual password since it is a trusted host.  This prevents having to deal with multiple passwords or password expiration issues within the RMX configuration.

In the 7.2 RMX software release there are currently a limited number of meeting rooms which can be registered to Lync.  Both RMX 1500/2000 models support up to 10 simultaneously registered rooms, while the RMX 4000 supports up to 20.  In the next software release these limits will be increased to 24 and 48, respectively.

Lync Configuration

Before creating the Lync user account the name of the virtual meeting room must be selected.  (For simplicity’s sake the user logon name and SIP URI will use the same value, but this is not a requirement as only the SIP URI is important to the RMX for proper call routing.)

• Create a new Active Directory user object.  In this example an account name of msdemovmr was selected.

• Enable the new Active Directory user account in Lync using either the Control Panel or the Management Shell.  The SIP Address (URI) in this example happens to match the user logon name, but as mentioned before this is not required.

Enable-CsUser -Identity SCHERTZ\msdemovmr -RegistrarPool lync.schertz.local -SipDomain mslync.net -SipAddress sip:msdemovmr@mslync.net

• Grant External User Access and Federated User Access to the new Lync account if external and/or federated contacts should be able to place video calls into virtual meeting room.  For internal-only scenarios this step can be skipped.

Grant-CsExternalAccessPolicy -Identity SCHERTZ\msdemovmr -PolicyName “External Access”

In this example Lync has a User policy called ‘External Access’ with these levels enabled and that policy was assigned to the new user. If the Global policy already has these levels enabled then external and federated access will work by default.

RMX Configuration

As mentioned in the prerequisites section above the RMX is already configured for basic Lync integration, which includes defining the selected SIP domain.  Typically the default or primary SIP domain is used, but when more than one SIP domain exists in Lync it is important to understand that the registered VMRs will need to utilize Lync accounts with SIP URIs defined in the same SIP domain.

The Server Domain Name setting in the RMX SIP Servers configuration must match the SIP URI for the Lync account created for this purpose (e.g. mslync.net).

The additional configuration on the RMX simply requires that a Conference Profile is enabled for SIP registration, and that a Meeting Room is created specifically to match the new Lync user account.

Only one Conference Profile per RMX can be configured for SIP registration, so all registered meeting rooms will need to use this same profile. (This limits all registered meeting rooms to the same settings for Line Rate, Encryption, Layouts, etc. To leverage multiple different meeting room configurations for Microsoft SIP callers then the traditional static routing integration needs to be used.)

• Using the RMX management console create a new Conference Profile (or edit an existing profile).  On the Network Services tab enable the SIP Registration checkbox.

• Next create a new Meeting Room on the RMX.  Enter the user name portion of Lync account’s SIP URI for the Routing Name.  (e.g. msdemovmr).  The Display Name can be anything, although matching the Lync account’s display name is recommended.  The ID can be any valid, unique numeric range used to route calls to that specific meeting room.

• Once the new meeting room is created check the Meeting Rooms list and verify the SIP Registration status of the new room shows as ‘OK’ and ‘Registered’.

• Presence should now be displayed as Available in Lync for this user account.  Audio and Video calls to this VMR will also be functional at this point.

Routing Name Requirements

The Routing Name of the RMX Meeting Room must exactly match the SIP URI of the Lync account to be registered as. Do not include the entire SIP URI (e.g. msdemovmr@mslync.net), only enter the user name portion of the address (e.g. msdemovmr).

Also make sure that the Routing Name is entered all in lowercase.  This is important as although SIP is not case sensitive H.323 can be, and the RMX supports the unique case-sensitivity of H.323 in this field.  So regardless how the case is configured on the Lync server it must always be entered in lowercase on the RMX Meeting Room as the SIP INVITE will automatically use lowercase in the addresses. (A suggested practice to help avoid this potential issue as well as simplify the configuration would be to use the numerical ID for the Routing Name and SIP URI, as numbers do not have different cases.)

To demonstrate this behavior the SIP Address for a Lync account was configured to use a mixture of upper and lower case letters.  This same format is retained throughout the Control Panel and Management Shell since the raw attribute itself was stored in this format.

But when looking at a SIP INVITE it is evident that all SIP URIs are sent in lowercase characters only.

Instance-Id: 0000071D
Direction: incoming
Peer: lync.schertz.local:52716
Message-Type: request
Start-Line: INVITE sip:msdemovmr@mslync.net;maddr=lync.schertz.local SIP/2.0
From: <sip:jeff@mslync.net>;tag=48b45ea5e1;epid=172d0a520e
To: <sip:msdemovmr@mslync.net>
CSeq: 1 INVITE
Call-ID: 16dcda1fdf954cecb83365e33c73f122

This lowercase SIP URI must match the configured Meeting Room, otherwise the call will be incorrectly dropped into the default entry queue on the RMX.  Hence the requirement to use only lowercase characters in the Routing Name.