Reliable communications using a point to point protocol
This disclosure describes techniques for performing communications between devices using various aspects of Ethernet standards. As further described herein, a protocol is disclosed that may be used for communications between devices, where the communications take place over a physical connection complying with Ethernet standards. Such a protocol may enable reliable and in-order delivery of frames between devices, while following Ethernet physical layer rules, Ethernet symbol encoding, Ethernet lane alignment, and/or Ethernet frame formats.
1. A network system comprising:
a source device;
an Ethernet physical layer connection; and
a destination device connected to a destination host device, wherein the destination device is connected to the source device over the Ethernet physical layer connection, and
wherein the destination device is configured to:
receive a frame over the Ethernet physical layer connection from the source device by receiving, in order, an Ethernet preamble, an Ethernet start frame delimiter, a twelve-byte field, a two-byte type field, a data field, and a four-byte Ethernet frame check sequence calculated based on the frame, determine, based on the two-byte type field, that the frame is not to be interpreted as an Ethernet frame,
parse, from the twelve-byte field included within the frame, a frame sequence number, and
parse, from the twelve-byte field, an acknowledge sequence number and bandwidth allocation information,
wherein the bandwidth allocation information identifies a virtual channel and a credit number associated with the virtual channel.
2. The network system of claim 1 ,
wherein the destination device allocates a plurality of virtual channels for sending information to the source device, and wherein the destination device adjusts, based on the credit number, how much information is sent over the virtual channel.
3. The network system of claim 1 , wherein at least one of the source device and the destination device is configured to:
allocate bandwidth between Ethernet frames and frames that are not to be interpreted as Ethernet frames.
4. The system of claim 1 , wherein the destination device is further configured to:
parse, from the data field, a plurality of messages from the frame, wherein each of the plurality of messages includes a message header and a message payload.
5. The system of claim 4 , wherein each of the message headers includes information identifying a message type, a virtual channel, and a length.
6. The system of claim 4 , wherein the plurality of messages includes:
a first message including an eight-byte address; and
a second message including data associated with the address.
7. The system of claim 6 , wherein the data associated with the address is 64 bytes.
8. The system of claim 5 , wherein at least some of the plurality of messages are associated with a different virtual channel.
9. The system of claim 5 , wherein the destination device is further configured to:
determine a rate for at least one identified virtual channel; and
control the bandwidth for the identified virtual channel.
10. The system of claim 4 , wherein at least one of the plurality of messages is marked with an error, wherein a subset of the plurality of messages are not marked with an error, and wherein the destination device is further configured to:
process only the subset of the plurality of messages.
11. The system of claim 1 , wherein the destination device is further configured to:
prior to receiving the frame, establish communications with the sending device over the Ethernet physical layer.