Data transmission method, core forwarding device, and endpoint forwarding device

Patent metadata

Field	Value
Publication number	US-9967201-B2
Application number	US-201615185355-A
Country	US
Kind code	B2
Filing date	Jun 17, 2016
Priority date	Dec 20, 2013
Publication date	May 8, 2018
Grant date	May 8, 2018

Abstract

A data transmission method, a core forwarding device, and an endpoint forwarding device, where the data transmission method includes, an end-to-end flow control technology that is established between a core device and an endpoint device of a system using the core forwarding device and the endpoint forwarding device, resolving a technical problem in the prior art that a uniform back pressure is generated in an entire data transmission link when any endpoint device generates back pressure when peripheral component interconnect express (PCIe) data is transmitted through the Ethernet, thereby achieving technical effects of increasing bandwidth utilization of the entire system and increasing the data transmission efficiency.

First claim

What is claimed is:

1. A data transmission method, comprising:
receiving, by a core forwarding device through a first virtual channel in a peripheral component interconnect express (PCIe) channel, a first PCIe packet sent by a core device, wherein a first traffic class of the first PCIe packet is allocated by the core device according to a destination-end device of the first PCIe packet, wherein the first traffic class is in a one-to-one correspondence with the destination-end device, and wherein the first virtual channel is in a one-to-one correspondence with the first traffic class;
encapsulating, by the core forwarding device according to the destination-end device, the first PCIe packet into a first Ethernet frame that has a first priority;
sending, by the core forwarding device, the first Ethernet frame to a network switching device through a first-priority channel that is in a one-to-one correspondence with the first priority and is in an Ethernet channel, when a first-priority buffer that is configured to store the first Ethernet frame is not under back pressure;
receiving, by the core forwarding device through a second-priority channel in the Ethernet channel, a second Ethernet frame sent by the network switching device, wherein a second priority of the second Ethernet frame is in a one-to-one correspondence with the second-priority channel;
parsing, by the core forwarding device, the second Ethernet frame to obtain a second PCIe packet, wherein a second traffic class of the second PCIe packet is in a one-to-one correspondence with a source-end device of the second PCIe packet; and
sending, by the core forwarding device, the second PCIe packet to the core device through a second virtual channel that is in a one-to-one correspondence with the second traffic class and is in the PCIe channel, when a first sending buffer that is configured to store the second PCIe packet is not under back pressure.

2. The method according to claim 1 , further comprising:
receiving, by the core forwarding device through the first-priority channel, a first back pressure signal sent by the network switching device after the first Ethernet frame is sent to the network switching device through the first-priority channel that is in the one-to-one correspondence with the first priority and is in the Ethernet channel;
stopping, by the core forwarding device according to the first back pressure signal, sending the first PCIe packet to the network switching device through the first-priority channel;
generating, by the core forwarding device, a second back pressure signal according to the first back pressure signal; and
sending the second back pressure signal to the core device through the first virtual channel.

3. The method according to claim 1 , further comprising:
receiving, by the core forwarding device through the second virtual channel, a third back pressure signal sent by the core device, after the second PCIe packet is sent to the core device through the second virtual channel that is in the one-to-one correspondence with the second traffic class and is in the PCIe channel;
stopping, by the core forwarding device according to the third back pressure signal, sending the second PCIe packet to the core device through the second virtual channel;
generating, by the core forwarding device, a fourth back pressure signal according to the third back pressure signal; and
sending the fourth back pressure signal to the network switching device through the second-priority channel.

4. The method according to claim 2 , wherein a sending buffer of the core forwarding device comprises a first-type sending buffer and a second-type sending buffer, wherein the first-type sending buffer is a buffer that is in the one-to-one correspondence with a specified virtual channel when the core forwarding device receives a specified packet through the specified virtual channel in the PCIe channel, wherein the second-type sending buffer is another buffer, other than the first-type sending buffer, in the sending buffer of the core forwarding device, and wherein generating, by the core forwarding device, the second back pressure signal according to the first back pressure signal further comprises:
generating, by the core forwarding device, the second back pressure signal when the first back pressure signal is to exert back pressure on the first-type sending buffer and when a volume of data stored in the first-type sending buffer exceeds a first threshold; and
generating, by the core forwarding device, the second back pressure signal when the first back pressure signal is to exert back pressure on the second-type sending buffer and when a volume of data stored in the second-type sending buffer exceeds the first threshold.

5. The method according to claim 4 , wherein after generating, by the core forwarding device, the second back pressure signal when the first back pressure signal is to exert back pressure on the second-type sending buffer and when the volume of data stored in the second-type sending buffer exceeds the first threshold, the method further comprises generating, by the core forwarding device, a specified back pressure signal, to exert back pressure on a first PCIe sending buffer in the core device when the volume of the data stored in the second-type sending buffer exceeds a second threshold, wherein the second threshold is greater than the first threshold.

6. A data transmission method, comprising:
receiving, by an endpoint forwarding device through a first-priority channel in an Ethernet channel, a first Ethernet frame sent by a network switching device, wherein the first Ethernet frame has a first priority that is in a one-to-one correspondence with the first-priority channel;
parsing, by the endpoint forwarding device, the first Ethernet frame to obtain a first peripheral component interconnect express (PCIe) packet, wherein a first traffic class of the first PCIe packet is in a one-to-one correspondence with a destination-end device of the first PCIe packet;
sending, by the endpoint forwarding device, the first PCIe packet to an endpoint device through a PCIe channel, wherein the endpoint device is consistent with the destination-end device, when a first sending buffer that is configured to store the first PCIe packet is not under back pressure;
receiving, by the endpoint forwarding device through the PCIe channel, a second PCIe packet sent by the endpoint device, wherein a second traffic class of the second PCIe packet is in a one-to-one correspondence with the endpoint device;
encapsulating, by the endpoint forwarding device according to the endpoint device, the second PCIe packet into a second Ethernet frame that has a second priority; and
sending, by the endpoint forwarding device, the second Ethernet frame to the network switching device through a second-priority channel that is in a one-to-one correspondence with the second priority and is in the Ethernet channel when a second-priority buffer that is configured to store the second Ethernet frame is not under back pressure.

7. The method according to claim 6 , further comprising:
receiving, by the endpoint forwarding device through the PCIe channel, a first back pressure signal sent by the endpoint device, after the first PCIe packet is sent to the endpoint device through the PCIe channel;
stopping, by the endpoint forwarding device, sending the first PCIe packet to the endpoint device through the PCIe channel;
generating, by the endpoint forwarding device, a second back pressure signal according to the first back pressure signal;
sending the second back pressure signal to the network switching device through the first-priority channel;
receiving, by the endpoint forwarding device through the second-priority channel, a third back

Assignees

• Huawei Tech Co Ltd

Inventors

• Xu Dong
• Wang Fu
• Wu Pei

Classifications

• H04L61/2592

  using tunnelling or encapsulation · CPC title

• H04L45/745

  Address table lookup; Address filtering · CPC title

• H04L12/4633

  Interconnection of networks using encapsulation techniques, e.g. tunneling · CPC title

• H04L69/22

  Parsing or analysis of headers · CPC title

• H04L12/413 Primary

  with random access, e.g. carrier-sense multiple-access with collision detection [CSMA-CD] · CPC title