2.2.1 Message Structures

The client uses the Autodiscover Publishing and Lookup Protocol, as specified in [MS-OXDSCLI], to discover the Web Distribution Point (WDP)URI, and then it constructs a manifest URI by appending the well-known name "oab.xml", as specified in the following ABNF:

manifestURI    = wdpUri "/oab.xml"

The client then retrieves the manifest file by using the standard HTTP/1.1 protocol, as specified in [RFC2616]. The manifest file contains information about the OAL data sequence number and the names of the data files that are published to a given WDP. The detailed structure of the manifest file is specified in the next section.

After the client retrieves and parses the manifest file, it ascertains what OALs are associated with this OAB. The client can retrieve each OAL in the OAB independently.

For each file that has to be retrieved, the client constructs the URI according to the following definition, and then it retrieves each of those URIs by using the HTTP/1.1 protocol [RFC2616], as follows:

dataFileURI = wdpUri "/" file