Microsoft have provided information on the Active Directory Schema extensions for Lync Server 2010. The documentation fails to provide information on the Search Flags and which attributes are added to the Global Catalog.
Based on Global Catalog Memberships (IsMemberOfPartialAttributeSet), I have extracted the infomation from the Lync Server 2010 Schema (LDF) files. They can be viewed in XLS format. Lync Server 2010 – PAS and Search Flags
This information is important when it comes to trying to gain an understanding on how your DC’s/GC’s may be impacted upon a Schema Upgrade.
The Search flags in the XLS mean:
1 = Index over attribute only. Bit 0 must be set (0001).
2 = Index the attribute in each container (this value is used in conjunction with 1). Bit 0 and bit 1 must be set (0011).
4 = Add this attribute to the ANR set (this value is used in conjunction with 1). Bit 0 and bit 2 must be set (0101).
8 = Preserve this attribute on logical deletion (that is, make this attribute available on tombstones). Bit 3 must be set (1000).
16 = Copy the value for this attribute when the user object is copied. You can use this value to set up a user object template so that you can create multiple users by making copies of an original and providing values for only those attributes that are unique to each user. Bit 4 must be set (10000).
32 = Index this attribute for medial-string search (this value is used in conjunction with 1). Bit 5 and bit 0 must be set (100001). This indexing capability is provided on domain controllers running Windows Server 2003 (or greater) when the schema has been updated for Windows Server 2003 functionality.
Note: if the Search Flags are set to 5 then then Search Flags 1 and 4 have been set.
More information on Active Directory Search flags can be found here