Segmented link training

Patent metadata

Field	Value
Publication number	US-2025141782-A1
Application number	US-202418432312-A
Country	US
Kind code	A1
Filing date	Feb 5, 2024
Priority date	Oct 30, 2023
Publication date	May 1, 2025
Grant date	—

Abstract

Techniques are provided to extend training to an end-to-end method, where a ready-to-send (RTS) variable is added to training frames to indicate that, on a current interface, the Physical Medium Attachment (PMA) sublayer, with all its lanes, has valid data and appropriate clock timing and is ready to send data to the output when training is completed. These techniques are applicable to a PMA that is an endpoint (and thus has only a single network interface involved) as well as to PMAs that have two network interfaces connected to segment partners. Moreover, these techniques may be configured to work with legacy devices that do not support segmented link training.

First claim

What is claimed is:

1 . A method performed by a device that is part of a multi-segment network link, the method comprising:
on a network interface facing a segment partner, receiving incoming training frames from the segment partner and transmitting outgoing training frames to the segment partner; and including a ready-to-send indication in an outgoing training frame to be sent to the segment partner, wherein the ready-to-send indication indicates that the device has, on all lanes of the network interface, valid data and is ready to send data on the network interface to the segment partner.

2 . The method of claim 1 , further comprising:
determining when an incoming training frame received from the segment partner includes a receiver ready indication, wherein including comprises including the ready-to-send indication when the device has a receiver ready indication and a received incoming training frame from the segment partner has a receiver ready indication on all lanes.

3 . The method of claim 1 , wherein the ready-to-send indication is a single bit that is included in a bit of a status field of a training frame, a first state of the single bit indicating that no data is available and training is to continue and a second state of the single bit indicating to switch to data mode when training is complete.

4 . The method of claim 1 , further comprising, when both the ready-to-send indication is included and a received incoming training frame from the segment partner has a receiver ready indication, after a period of time, switching the network interface from transmitting outgoing training frames to transmitting data.

5 . A method performed by a device that is part of a multi-segment network link, the method comprising:
on a first network interface facing a first segment partner, receiving incoming training frames from the first segment partner and transmitting outgoing training frames to the first segment partner; on a second network interface facing a second segment partner, receiving incoming training frames from the second segment partner and transmitting outgoing training frames to the second segment partner; first including a first ready-to-send indication, when the first ready-to-send indication is included in an incoming training frame received from the first segment partner, in an outgoing training frame to be sent to the second segment partner; and second including a second ready-to-send indication, when the second ready-to-send indication is included in an incoming training frame received from the second segment partner, in an outgoing training frame to be sent to the first segment partner.

6 . The method of claim 5 , wherein the first ready-to-send indication indicates that the first segment partner has, on all lanes, valid data and is ready to send data to the device on the first network interface, and the second ready-to-send indication indicates that the second segment partner has, on all lanes, valid data and is ready to send data to the device on the second network interface.

7 . The method of claim 5 , further comprising:
determining when an incoming training frame received from the first segment partner includes an incoming receiver ready indication; and including an outgoing receiver ready indication in an outgoing training frame transmitted to the first segment partner, wherein the first including and the second including are performed when the incoming receiver ready indication is detected in an incoming training frame and when the outgoing receiver ready indication is included in an outgoing training frame.

8 . The method of claim 7 , wherein the first including comprises including the first ready-to-send indication in an outgoing training frame to be sent to the second segment partner when the device has a receiver ready indication and a received incoming training frame from the first segment partner has a receiver ready indication of the first segment partner on all lanes and a received incoming training frame from the second segment partner has a receiver ready indication of the second segment partner on all lanes.

9 . The method of claim 7 , wherein the second including comprises including the second ready-to-send indication in an outgoing training frame to the first segment partner when the device has a receiver ready indication and a received incoming training frame from the first segment partner has a receiver ready indication of the first segment partner on all lanes and a received incoming training frame from the second segment partner has a receiver ready indication of the second segment partner on all lanes.

10 . The method of claim 5 , wherein the first ready-to-send indication is a single bit that is included in a bit of a status field of a training frame, a first state of the single bit indicating that no data is available and training is to continue and a second state of the single bit indicating to switch to data mode when training is complete.

11 . The method of claim 5 , further comprising:
when both the first ready-to-send indication and the second ready-to-send indication are received, after a period of time, switching the first network interface from transmitting outgoing training frames to transmitting data that is received from the second network interface, and switching the second network interface from transmitting outgoing training frames to transmitting data that is received from the first network interface.

12 . A method performed by a device that is part of a multi-segment network link, the method comprising:
disabling a first transmitter on a first network interface of the device for a period of time; disabling a second transmitter on a second network interface of the device; on a first network interface facing a first segment partner, receiving incoming training frames from the first segment partner; after the period of time, enabling the first transmitter on the first network interface and transmitting outgoing training frames to the first segment partner; when a first ready-to-send indication is included in an incoming training frame received from the first segment partner, enabling the second transmitter and transmitting a binary pattern from a second network interface to a second segment partner; and when a receiver ready indication is determined for the second segment partner, including a second ready-to-send indication in an outgoing training frame transmitted to the first segment partner.

13 . The method of claim 12 , wherein the first ready-to-send indication indicates that the first segment partner has, on all lanes, valid data and is ready to send data to the device on the first network interface, wherein the second ready-to-send indication indicates that the second segment partner has, on all lanes, valid data, and is ready to send data to the device on the second network interface.

14 . The method of claim 12 , wherein the first ready-to-send indication is a single bit that is included in a bit of a status field of a training frame, a first state of the single bit indicating that no data is available and training is to continue and a second state of the single bit indicating to switch to data mode when training is complete.

15 . The method of claim 12 , further comprising:
when the first ready-to-send indication is received and the second ready-to-send indication is included in an outgoing training frame to the first segment partner, after a period of time, switching the first network interface from transmitting outgoing training frames to transmitting data that is received from the second network interface, and

Assignees

• Cisco Tech Inc

Inventors

• Ran Adee O

Classifications

• H04L45/24 Primary

  Multipath · CPC title