Transmission and Reception Devices

摘要

A method and devices for reducing the delay in end-to-end delivery of network packets may be achieved by having the transmission (TX) side of the device, tag each cell with a unique packet identifier and with a byte offset parameter where the tagging allows the reception (RX) side of the destination device to perform on-the-fly assembly of cells into packets by directly placing them at corresponding host buffer, and the method may be done for multiple packets concurrently, and hence store and forward buffering is not needed in either the source or the destination devices and the lowest possible end-to-end cut-through latency is achieved.

主权项

1. A transmission device, comprising:
a processor configured to:
submit multiple read request messages over a host interface corresponding to buffers of one or more network packets;assign for each network packet a unique packet identifier;calculate for each read request message a start byte offset indicating a relative location of a first completion byte of the read request message within the original network packet;store the unique packet identifier and the start byte offset as an entry within a transmission database,wherein upon arrival of completion data from the host interface for the submitted read request messages, for each read response message, the processor is further configured to:
associate the read response message with the entry of the transmission database;extract the packet identifier; andtransform the read response message into a fabric cell by the following operations:mark the fabric cell with the packet identifier;mark the fabric cell with a byte offset indicating a relative start byte offset of the fabric cell within the associated network packet, wherein the byte offset is calculated by summing a relative start offset of the corresponding read request message and a location of the read response message within an entire stream of completion bytes of that read request message;mark the fabric cell with a first flag when the fabric cell represents a first fabric cell of the network packet;mark the fabric cell with a last flag when the fabric cell represents a last fabric cell of the network packet;release the transmission database entry when the fabric cell is marked with the last flag; andsubmit the fabric cell over a fabric interface.