Method, device, and system for deferring switchback

Patent metadata

Field	Value
Publication number	US-11146484-B2
Application number	US-201715614057-A
Country	US
Kind code	B2
Filing date	Jun 5, 2017
Priority date	Dec 5, 2014
Publication date	Oct 12, 2021
Grant date	Oct 12, 2021

Abstract

A method, a device, and a system for deferring a switchback. A first network device sends a query packet to a second network device, detects, according to the query packet, whether a route from the second network device to a destination device is available after receiving the query packet, and when it is available, the second network device sends a query response packet to the first network device in order to trigger the first network device to switch back from a secondary route to a primary route. The technical solution provided reduces a wait-to-restore time of the switchback, ensures that service data transmitted from the first network device to the second network device can be transmitted to the destination device, and facilitates smooth transmission of the service data.

First claim

What is claimed is:

1. A method for deferring a switchback, comprising:
sending, by a first network device responsive to restoring a connection to a second network device, a query packet to the second network device to trigger the second network device to detect whether a route between the second network device to a destination device is available to enable the first network device to defer switchback from a secondary route to a primary route until the primary route is available,
wherein the second network device is a primary network device on the primary route from the first network device to the destination device,
wherein a third network device is a secondary network device on the secondary route from the first network device to the destination device,
wherein the second network device is a next hop on the primary route and the third network device is a next hop on the secondary route, and
wherein the first network device switches to the secondary route to the destination device using the third network device instead of the second network device responsive to a failure of the second network device;

receiving, by the first network device, a query response packet from the second network device; and
switching back, by the first network device, from the secondary route to the primary route responsive to the query response packet indicating availability of the route between the second network device and the destination device.

2. The method of claim 1 , wherein the connection comprises a traffic engineering (TE) tunnel connection to the second network device.

3. The method of claim 1 , wherein switching back from the secondary route to the primary route, comprises:
creating, by the first network device, a forwarding entry of the primary route;
activating, by the first network device, the forwarding entry; and
forwarding, by the first network device, a data packet to the second network device using the forwarding entry.

4. The method of claim 1 , further comprising generating, by the first network device, a forwarding entry of the primary route before sending the query packet to the second network device, wherein switching back from the secondary route to the primary route comprises:
activating, by the first network device, the forwarding entry; and
forwarding, by the first network device, a data packet to the second network device using the forwarding entry.

5. The method of claim 1 , wherein the first network device is a network provider edge (NPE) device or a provider edge (PE) device, and wherein the second network device and the third network device are superstratum provider edge (SPE) devices or NPE devices.

6. A method for deferring a switchback, comprising:
receiving, by a second network device, a query packet from a first network device responsive to restoring a connection with the first network device, wherein the second network device is a primary network device;
detecting, by the second network device responsive to receiving the query packet, whether a route from the second network device to a destination device is available to enable the first network device to defer switchback from a secondary route to a primary route until the primary route is available,
wherein the second network device is a primary network device on the primary route from the first network device to the destination device,
wherein a third network device is a secondary network device on the secondary route from the first network device to the destination device,
wherein the second network device is a next hop on the primary route and the third network device is a next hop on the secondary route, and
wherein the first network device switches to the secondary route to the destination device using the third network device instead of the second network device responsive to a failure of the second network device; and

sending, by the second network device, a query response packet to the first network device when the route from the second network device to the destination device is available, wherein the query response packet indicates availability of the route between the second network device and the destination device, and wherein the query response packet is configured to trigger the first network device to switch back from the secondary route to the primary route.

7. The method of claim 6 , wherein detecting whether the route from the second network device to the destination device is available comprises:
querying, by the second network device, whether a backup of an Address Resolution Protocol (ARP) table from the third network device is completed; and
querying, by the second network device, whether an ARP entry corresponding to an Internet Protocol (IP) address of the destination device exists in the backup ARP table when the second network device completes the backup of the ARP table from the third network device.

8. The method of claim 6 , wherein detecting whether the route from the second network device to the destination device is available comprises:
generating, by the second network device, an Address Resolution Protocol (ARP) table using a preset ARP configuration file; and
querying, by the second network device, whether an ARP entry corresponding to an Internet Protocol (IP) address of the destination device exists in the ARP table.

9. The method of claim 7 , further comprising detecting, by the second network device, whether a pseudo wire (PW) from the second network device to a fourth network device is available when the ARP entry corresponding to the IP address of the destination device exists, wherein the fourth network device is connected to the destination device.

10. The method of claim 7 , further comprising detecting, by the second network device, whether a protection pseudo wire (PW) from the second network device to the third network device is available when the ARP entry corresponding to the IP address of the destination device exists, wherein the protection PW is an inter-chassis backup (ICB) PW or a dual-node interconnection (DNI) PW.

11. A first network device for deferring a switchback, comprising:
a processor;
a transmitter coupled to the processor and configured to send, responsive to restoring a connection to a second network device, a query packet to the second network device to trigger the second network device to detect whether a route between the second network device to a destination device is available to enable the first network device to defer switchback from a secondary route to a primary route until the primary route is available,
wherein the second network device is a primary network device on the primary route from the first network device to the destination device,
wherein a third network device is a secondary network device on the secondary route from the first network device to the destination device,
wherein the second network device k a next hop on the primary route and the third network device is a next hop on the secondary route, and
wherein the first network device switches to the secondary route to the destination device using the third network device instead of the second network device responsive to a failure of the second network device;

a receiver coupled to the processor and configured to:
receive a query response packet from the second network device; and
send the query response packet to the processor,

wherein the processor is configured to:
generate the query packet;
send the query packet to the transmitter; and
switch back from the secondary route to the primary route after the receiver receives the query response packet from the second network device, wherein the query response packet indicates availability of the

Assignees

• Huawei Tech Co Ltd

Inventors

• Zhang Yaokun
• Sun Chunxia

Classifications

• H04L45/22

  Alternate routing · CPC title

• H04L45/28 Primary

  using route fault recovery · CPC title

• H04L41/0654

  using network fault recovery (ring fault isolation or reconfiguration in loop networks without recovery actions by a network management system H04L12/437) · CPC title

• H04L41/0816

  the condition being an adaptation, e.g. in response to network events · CPC title