3.2.1.1.3 Receive Window (Call)

Receive Window: The client and server SHOULD implement an abstraction of a receive window in its call object to support an implementation of a sliding window algorithm. The Windows-based client and server call objects share a common packet-windowing implementation that maintains separate windows for the data to be sent and received. For a particular call, the receive window contains the following properties:

  • Received Fragment List: For every call, the client and server MUST maintain a list of received fragments indexed by fragment number, as defined in [C706] section 12.5.2.16, and also containing the fragment's serial number. The list is used to collect fragments until all fragments for the call have been received. All fragments have been received when the receiver has received a fragment with the flag value lastfrag, as defined in [C706] section 12.5.2.3, and all fragments are present from fragment number zero up to and including the fragment number of the fragment with lastfrag set.

    The Received Fragment List is initially empty at the beginning of a call. The Received Fragment List is deleted when a call is completed.

  • Receive Fragment Base: For a call, an integer variable that indicates the lowest fragment number which can be received and added to the Received Fragment List. A fragment with a fragment number greater than or equal to the Receive Fragment Base value is added to the Received Fragment List.

  • Receive serial number: The latest fragment serial number received in this call.