Tweaking OCS for PIC with Windows Live/MSN Messenger



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:



· 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



· 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





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




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
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.
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="">
<Provider Name="OCS User Services" />
<EventID Qualifiers="50158">30929</EventID>
<TimeCreated SystemTime="2009-08-20T13:30:31.000Z" />
<Channel>Office Communications Server</Channel>
<Security />



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