Summary:

 

Windows Live/MSN Messenger defines both Minimum and Maximum values for Presence subscriptions. If the SUBSCRIBE method uses a value out of this range, it may result in a SIP failure.  The minimum value is 3600 seconds and the MAX value is 13000 seconds.

 

 

More Information:

 

MinPresenceSubscriptionExpiry

 

·         Stored in the Active Directory as "msRTCSIP-MinPresenceSubscriptionTimeout"

·         The default value is 1200 seconds (20 minutes)

·         The minimum value for this property is 300 and the maximum value is 86340

 

MaxPresenceSubscriptionExpiry

 

·         Stored in the Active Directory as "msRTCSIP-MaxPresenceSubscriptionTimeout"

·         The default value is 43200 seconds (12 hours)

·         The minimum value for this property is 300 and the maximum value is 86340

 

 

Workaround:

 

If you are encountering SIP interoperability failures via PIC against Windows Live/MSN Messenger, please modify your msRTCSIP-MaxPresenceSubscriptionTimeout and msRTCSIP-MinPresenceSubscriptionTimeout values (either via ADSIEDIT or LDP) in accordance with their guidance (min: 3600, max: 13000)

 

 

If you have installed OCS into the System container in the Active Directory, these attributes will be stored at the following location:

 

CN=Global Settings,CN=RTC Service,CN=Microsoft,CN=System,DC=yourdomain,DC=com

 

 

If OCS is installed in the Configuration container, you can locate these values in the Active Directory here:

 

CN=Global Settings,CN=RTC Service,CN=Services,CN=Configuration,DC=yourdomain,DC=com

 

 

Update:

 

If for any reason the above-mentioned values get reset, they will then fall outside of the default values.  Consequently, you'll need to modify the msRTCSIP-DefPresenceSubscriptionTimeout value, as without correcting this to be within range, the OCS Front-End service will not start.  Additionally, you will find the following error in the Office Communications Server Event Log:

 

Log Name:      Office Communications Server
Source:        OCS User Services
Date:          8/20/2009 6:30:31 AM
Event ID:      30929
Task Category: (1006)
Level:         Error
Keywords:      Classic
User:          N/A
Computer:      ocs.contoso.com
Description:
Failed to process WMI event to update the User Services Global Settings because the value of Attribute1 cannot be greater than the value of Attribute2.

Attribute1: DefPresenceSubscriptionExpiry Attribute2: MaxPresenceSubscriptionExpiry
Cause: This could happen during upgrades, or in topologies with mixed 1.0 and 2.0 servers or if the Active Directory is modified directly.
Resolution:
Use MMC (or WMI) to update all the values that are out of bounds.  The changes will take place without restarting the server.
Event Xml:
<Event xmlns="http://schemas.microsoft.com/win/2004/08/events/event">
  <System>
    <Provider Name="OCS User Services" />
    <EventID Qualifiers="50158">30929</EventID>
    <Level>2</Level>
    <Task>1006</Task>
    <Keywords>0x80000000000000</Keywords>
    <TimeCreated SystemTime="2009-08-20T13:30:31.000Z" />
    <EventRecordID>26728</EventRecordID>
    <Channel>Office Communications Server</Channel>
    <Computer>ocs.contoso.com</Computer>
    <Security />
  </System>
  <EventData>
    <Data>DefPresenceSubscriptionExpiry</Data>
    <Data>MaxPresenceSubscriptionExpiry</Data>
  </EventData>
</Event>

 

 

Credit to Jason Groves & Greg Anthony for the msRTCSIP-DefPresenceSubscriptionTimeout piece