4.2 Peer Transmits 500 Bytes of Data

The following message sequence shows the steps taken to transmit a small amount of data (500 bytes).

  • The peer uses the Send operation to transmit the data because the upper layer request did not provide an RDMA Buffer Descriptor. A Data Transfer message is sent that contains the 500 bytes of data as the message’s payload. The message requests 10 Send Credits to maintain the current credit limit and grants 1 Send Credit to replace the credit request used by the final message in section 4.1.

    • The Data Transfer message fields are set to the following:

      • CreditsRequested: 0x000A (10)

      • CreditsGranted: 0x0001

      • Flags: 0x0000

      • Reserved: 0x0000

      • RemainingDataLength: 0x000000 (nonfragmented message)

      • DataOffset: 0x00000018 (24)

      • DataLength: 0x000001F4 (500 = size of the data payload)

      • Padding: 0x00000000 (4 bytes of 0x00)

      • Buffer: (Upper layer message)