2.2.2.1 Discard Message

An initiator device sends this message to a sink device after it establishes a TCP/IP connection. When the sink receives this message, it MUST discard the message and prepare to receive subsequent messages on that connection. All these subsequent messages MUST be discarded immediately after the message is received, with no validation whatsoever.

This mechanism exists to give the initiator a very coarse mechanism to estimate the available bandwidth between itself and the sink through the inherent properties of TCP/IP acknowledgement. In other words, an initiator can very roughly estimate the available bandwidth if it measures the rate that it can send TCP/IP messages.