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 system comprising:
a first device connected to an Ethernet physical layer connection, wherein the first device is configured to: construct a frame having a twelve-byte field, a two-byte field, and a data field, wherein the two-byte field includes information identifying whether the frame is to be interpreted as an Ethernet frame, output the frame over the Ethernet physical layer connection by transmitting the twelve-byte field, followed by the two-byte field, and followed by the data field, and output, over the Ethernet physical layer connection, an Ethernet frame check sequence calculated based on the frame; and a second device connected to the Ethernet physical layer connection, wherein the second device is configured to: receive the frame over the Ethernet physical layer connection, determine, based on the two-byte field, whether the frame is to be interpreted as an Ethernet frame, and communicate with the first device;
wherein the second device is further configured to: parse, from the data field, a plurality of messages included within the frame, wherein each of the plurality of messages includes a message header and a message payload;
wherein the plurality of messages includes a message marked with an error, and wherein the second device is further configured to: refrain from processing the message marked with an error.
2. The system of claim 1 , wherein to determine whether the frame is to be interpreted as an Ethernet frame, the second device is further configured to:
determine, based on the two-byte field, that the frame is not to be interpreted as an Ethernet frame.
3. The system of claim 2 , wherein the frame is a first frame, wherein the twelve-byte field is a first frame twelve-byte field, wherein the two-byte field is a first frame two-byte field, and wherein the data field is a first frame data field, and wherein to communicate with the first device, the second device is further configured to:
construct a second frame having a second frame twelve-byte field, a second frame two-byte field, and a second frame data field, wherein the second frame two-byte field includes information specifying that the second frame is not to be interpreted as an Ethernet frame; and
output the second frame over the Ethernet physical layer connection to the first device by transmitting the second frame twelve-byte field, followed by the second frame two-byte field, and followed by the second frame data field.
4. The system of claim 3 , wherein the Ethernet frame check sequence is a first frame Ethernet frame check sequence, and wherein to communicate with the first device, the second device is further configured to:
output, over the Ethernet physical layer connection, a second frame Ethernet frame check sequence calculated based on the second frame.
5. The system of claim 3 , wherein the second device is further configured to:
acknowledge receipt of the first frame.
6. The system of claim 5 , wherein to acknowledge receipt of the first frame, the second device is configured to:
include an acknowledgement of the first frame within the second frame twelve-byte field.
7. The system of claim 6 , wherein to construct the first frame, the first device is configured to:
include, within the first frame twelve-byte field, a sequence number identifying the first frame.
8. The system of claim 7 , wherein to include an acknowledgment of the first frame within the second frame, the second device is configured to:
include the sequence number identifying the first frame within the second frame twelve-byte field.
9. The system of claim 8 , wherein the sequence number is included within a plurality of earlier sequential numbers, and wherein the first device is further configured to:
receive, over the Ethernet physical layer connection, the second frame;
parse, from the second frame, the sequence number;
interpret the sequence number as acknowledging the first frame; and
interpret the sequence number as acknowledging another frame that has one of the earlier sequential numbers.
10. The system of claim 2 , wherein the frame is a first frame, wherein the twelve-byte field is a first frame twelve-byte field, wherein the two-byte field is a first frame two-byte field, and wherein the data field is a first frame data field, and wherein to communicate with the first device, the second device is further configured to:
construct a second frame having a second frame twelve-byte field, a second frame two-byte field, and a second frame data field, wherein the second frame two-byte field includes information specifying that the second frame is to be interpreted as an Ethernet frame; and
output the second frame over the Ethernet physical layer connection and to the first device by transmitting the second frame twelve-byte field, followed by the second frame two-byte field, and followed by the second frame data field.
11. The system of claim 1 , wherein the second device is further configured to:
establish communications with the first device over the Ethernet physical layer connection prior to receiving the frame.
12. The system of claim 1 , wherein the first device is further configured to:
allocate bandwidth between Ethernet frames and frames that are not to be interpreted as Ethernet frames.