Transmitter that does not resend a packet despite receipt of a message to resend the packet

Patent metadata

Field	Value
Publication number	US-10789115-B2
Application number	US-201415513908-A
Country	US
Kind code	B2
Filing date	Oct 9, 2014
Priority date	Oct 9, 2014
Publication date	Sep 29, 2020
Grant date	Sep 29, 2020

Abstract

A processing device includes an internal transmitter to receive packets and to forward those packets across a link to an external receiver external to the processing device. The internal transmitter is to receive a portion of a packet and to begin transmitting the portion across the link to the external receiver before the entire overall packet, of which the portion is a part, is received and validated. For a packet determined to have an error, the internal transmitter does not resend the overall packet across the link even if a message is received from the external receiver to resend the overall packet.

First claim

What is claimed is:

1. A processing device, comprising:
an internal upstream receiver internal to the processing device to receive packets from an upstream link and to validate the received packets;
an internal downstream transmitter downstream to the internal upstream receiver to receive packets from the internal upstream receiver and to forward those packets across a downstream link to an external receiver external to the processing device; and
a retry buffer accessible to the internal downstream transmitter, wherein a respective entry in the retry buffer comprises a packet-information field and an error-information field;
wherein the internal downstream transmitter is to receive a portion of a packet from the internal upstream receiver and to begin transmitting the portion across the downstream link to the external receiver before the entire overall packet, of which the portion is a part, is received and validated by the internal upstream receiver that is upstream to the internal downstream transmitter;
wherein the internal downstream transmitter is to set at least one bit in the error-information field of an entry corresponding to the overall packet in the retry buffer in response to receiving an error message from the internal upstream receiver, and not resend the overall packet across the downstream link even if a message is received from the external receiver to resend the overall packet;
wherein the internal upstream receiver is to receive the overall packet across an upstream link from an external transmitter external to the processing device and to forward the portion of the overall packet to the internal downstream transmitter before the internal upstream receiver validates the entire overall packet; and
wherein, after forwarding the portion to the internal downstream transmitter, the internal upstream receiver is to detect an error in the overall packet and to inform the internal downstream transmitter of the error for the internal downstream transmitter to thereby determine the overall packet to have the error.

2. The processing device of claim 1 , wherein the downstream transmitter is to respond to receipt of the request for a retry of a packet that has an error by transmitting a message to the external receiver to drop the packet and cease requesting a retry.

3. The processing device of claim 1 , wherein the upstream receiver detects the error based on error-detection information included in the overall packet.

4. A processing device, comprising:
a downstream transmitter;
an upstream receiver that is upstream to the downstream transmitter, wherein the upstream receiver is to receive packets over an upstream link, to validate each received packet, and to perform cut-through routing to the downstream transmitter in which portions of a packet are to be forwarded from the upstream receiver to the downstream transmitter before the entire packet is validated by the upstream receiver; and
a retry buffer to include a plurality of entries, each entry to include a packet-information field and an error-information field indicating whether the packet corresponding to the packet information has experienced an error;
wherein the downstream transmitter also is to perform cut-through routing in which a portion of a packet received by the downstream transmitter from the upstream receiver is to be transmitted by the downstream transmitter across a downstream link to a downstream receiver before the packet is validated by the upstream receiver;
wherein the upstream receiver detects whether a given packet has an error and sends an error message to the downstream transmitter after the downstream transmitter has already transmitted at least one portion of the given packet across the downstream link to the downstream receiver;
wherein the downstream transmitter is to set at least one bit in the error-information field of an entry corresponding to the given packet in the retry buffer in response to receiving from the upstream receiver the error message; and
wherein the downstream transmitter is to implement link level retry in which the downstream transmitter is to retry a packet in the retry buffer across the downstream link to the downstream receiver upon request for a retry received over the downstream link if the at least one bit in the error-information field corresponding to the packet is not set in the retry buffer, but not to retry the packet if the at least one bit in the error-information field corresponding to the packet is set to indicate an error.

5. The processing device of claim 4 , wherein the downstream transmitter is to respond to receipt of the request for a retry of a packet that has an error by transmitting a message to the downstream receiver to drop the packet and cease requesting a retry.

6. The processing device of claim 4 , wherein the upstream receiver detects whether a given packet has an error based on error-detection information included in the given packet.

7. A method, comprising:
receiving portions of a packet at an upstream receiver;
providing a received portion to a downstream transmitter that is downstream to the upstream receiver before the packet is validated;
transmitting, by the downstream transmitter, the received portion across a downstream link to a downstream receiver;
adding an entry corresponding to the packet in a retry buffer, wherein the entry comprises a packet-information field and an error-information field;
detecting, by the upstream receiver, an error in the packet;
sending an error message from the upstream receiver to the downstream transmitter;
in response to receiving the error message from the upstream receiver, setting, by the downstream transmitter, at least one bit in the error-information field of the entry corresponding to the packet in the retry buffer;
receiving a message at the downstream transmitter from the downstream receiver to resend the packet across the downstream link; and
not resending the packet by the downstream transmitter across the downstream link.

8. The method of claim 7 wherein not resending the packet comprises examining the retry buffer to determine if the requested packet is corrupt.

9. The method of claim 7 , further comprising transmitting a message to the downstream receiver to drop the packet and cease requesting a retry.

10. The method of claim 7 , wherein detecting, by the upstream receiver, the error in the packet comprises analyzing error-detection information included in the packet.

Assignees

• Hewlett Packard Entpr Dev Lp

Inventors

• Lesartre Gregg B
• Regan James D
• Bockhaus John W

Classifications

• H04L49/251 Primary

  Cut-through or wormhole routing · CPC title

• H04L49/9068

  in the network interface card · CPC title

• G06F11/0772 Primary

  Means for error signaling, e.g. using interrupts, exception flags, dedicated error registers · CPC title

• H04L45/40

  Wormhole routing · CPC title

• H04L1/201

  Frame classification, e.g. bad, good or erased (frame indication per se H04L1/0082) · CPC title