4.2.1 On the Receiver when receiving the packet with next higher sequence number

  1. Refer to step 1–3 in section 4.1.2 for low level processing when a packet is received by the Receiver.

  2. Because the DATA payload is present, the Receiver obtains both the channel sequence number and the sequence number. In this scenario both sequence numbers are higher by 2 from those of the last received packet.

  3. The Receiver forwards the packet to the Receiver reliability controller. And it is buffered without forwarding because there is still a missing packet to arrive before it can be forwarded (section 3.1.1.2.4.2).

  4. The Receiver updates the circular upper bound of the active range of the Receiver window buffer to point to the newest sequence number just received. For the hole created for the missing sequence number, it is marked as Pending (section 3.1.1.2.2).

  5. The Receiver flushes any pending acknowledgment packets by sending an acknowledgment packet to the Sender immediately (section 2.2.1.2.1).

  6. The Receiver constructs an acknowledgment vector packet containing the missing sequence number as the base sequence number, and the current received sequence number at the top in the acknowledgment vector, with valid timing information. The Receiver then sends this acknowledgment vector packet immediately (section 2.2.1.2.6).