Forwarding entry generation method, packet sending method, network device, and system

Patent metadata

Field	Value
Publication number	US-12407602-B2
Application number	US-202217890651-A
Country	US
Kind code	B2
Filing date	Aug 18, 2022
Priority date	Feb 21, 2020
Publication date	Sep 2, 2025
Grant date	Sep 2, 2025

Abstract

This application discloses a forwarding entry generation method, a packet sending method, a network device, and a system, so that a specified network device cannot use a backup forwarding path to forward a packet, thereby reducing, to some extent, a technical problem such as network resource waste or network congestion caused by a loop problem. The method includes: A first network device obtains routing information advertised by a second network device; and the first network device determines that the routing information advertised by the second network device matches a summary route stored in the first network device, and generates, based on a segment identifier of the second network device, a forwarding entry corresponding to the summary route. The forwarding entry includes the segment identifier of the second network device, and a forwarding path corresponding to the forwarding entry passes through the second network device.

First claim

What is claimed is:

1. A method for generating forwarding entries, comprising:
obtaining, by a first network device, routing information advertised by a second network device;
determining, by the first network device, that the routing information matches a summary route stored in the first network device, wherein the summary route includes a summary that summarizes at least one route corresponding to a destination address; and
generating, based on a segment identifier of the second network device, a forwarding entry corresponding to the summary route, wherein the forwarding entry comprises the segment identifier of the second network device and a forwarding path corresponding to the forwarding entry passes through the second network device,
wherein the forwarding entry is a backup forwarding entry corresponding to the summary route, a primary forwarding entry corresponding to the summary route does not pass through the second network device, and the method further comprises:
setting, by the first network device, the primary forwarding entry to an unavailable state.

2. The method according to claim 1 , wherein before generating the forwarding entry corresponding to the summary route, the method further comprises:
receiving, by the first network device, a first advertisement packet, wherein the first advertisement packet comprises the segment identifier of the second network device.

3. The method according to claim 2 , wherein the first advertisement packet further comprises first indication information, and the method further comprises:
matching, by the first network device based on the first indication information, the routing information against the summary route stored in the first network device; and
when it is determined that the routing information matches the summary route stored in the first network device, generating, based on the segment identifier of the second network device, the forwarding entry corresponding to the summary route.

4. The method according to claim 2 , wherein the first advertisement packet comprises the routing information advertised by the second network device; and
wherein obtaining the routing information comprises:
obtaining, by the first network device from the first advertisement packet, the routing information advertised by the second network device.

5. The method according to claim 2 , wherein the first advertisement packet further comprises a device identifier of the second network device; and
wherein obtaining the routing information comprises:
obtaining, by the first network device, the routing information advertised by the second network device based on the device identifier of the second network device and a correspondence between the device identifier of the second network device and the routing information advertised by the second network device.

6. The method according to claim 5 , further comprising:
receiving, by the first network device, a second advertisement packet that comprises the device identifier of the second network device and the routing information advertised by the second network device; and
generating, by the first network device, the correspondence based on the device identifier of the second network device and the routing information advertised by the second network device.

7. The method according to claim 3 , wherein the first advertisement packet comprises a segment routing over Internet protocol version 6 (SRv6) endpoint segment identifier (END SID) type length value (TLV), and the first indication information is carried in a Flags field, an Endpoint Behavior field, or a reserved field in the SRv6 END SID TLV.

8. The method according to claim 3 , wherein the first advertisement packet comprises a non-bypass segment identifier type length value (NoBypass SID TLV); and a Type field of the NoBypass SID TLV carries the first indication information; or a Type field of the NoBypass SID TLV carries second indication information, an Endpoint Behavior field of the NoBypass SID TLV carries the first indication information, and the second indication information is used to indicate that the Endpoint Behavior field carries the first indication information.

9. The method according to claim 2 , wherein the first advertisement packet is an open shortest path first (OSPF) packet or an intermediate system to intermediate system (ISIS) packet.

10. The method according to claim 1 , wherein determining that the routing information advertised by the second network device matches the summary route comprises:
determining, by the first network device, that a prefix in the routing information advertised by the second network device is the same as a prefix of the summary route and that a mask in the routing information advertised by the second network device is the same as a mask of the summary route.

11. The method according to claim 1 , further comprising:
receiving, by the first network device, a first packet having a destination address matching the summary route;
adding, by the first network device, the segment identifier of the second network device to a packet header of the first packet to obtain a second packet; and
sending, by the first network device, the second packet to the second network device based on the segment identifier of the second network device.

12. The method according to claim 11 , wherein the second packet comprises third indication information that is used to indicate the second network device to avoid using a backup forwarding path from the second network device to a destination device to forward the second packet.

13. A method for sending packets, comprising:
generating, by a second network device, a first advertisement packet having a segment identifier of the second network device; and
sending, by the second network device, the first advertisement packet to a first network device to instruct the first network device to generate, when it is determined that routing information advertised by the second network device matches a summary route stored in the first network device, a forwarding entry corresponding to the summary route, wherein the forwarding entry comprises the segment identifier of the second network device and a forwarding path corresponding to the forwarding entry through the second network device, wherein the summary route includes a summary that summarizes at least one route corresponding to a destination address,
wherein the forwarding entry is a backup forwarding entry corresponding to the summary route, a primary forwarding entry corresponding to the summary route does not pass through the second network device, and wherein
the primary forwarding entry is set by the first network device to an unavailable state.

14. The method according to claim 13 , wherein the first advertisement packet further comprises first indication information that is used to indicate the first network device to generate the forwarding entry corresponding to the summary route, when it is determined that the routing information matches the summary route stored in the first network device.

15. The method according to claim 14 , wherein the first advertisement packet comprises a segment routing over Internet protocol version 6 (SRv6) endpoint segment identifier (END SID) type length value (TLV), and the first indication information is carried in a Flags field, an Endpoint Behavior field, or a reserved field in the SRv6 END SID TLV.

16. The method according to claim 14 , wherein the first advertisement packet comprises a non-bypass segment identifier type length value (NoBypass SID TLV); and a Type field of the NoBypass S

Assignees

• Huawei Tech Co Ltd

Inventors

• Qiu Jun
• Hu Zhibo
• Chen Chuang

Classifications

• H04L45/247

  using M:N active or standby paths · CPC title

• H04L45/74

  Address processing for routing · CPC title

• H04L45/28

  using route fault recovery · CPC title

• H04L45/02

  Topology update or discovery · CPC title

• H04L45/741

  Routing in networks with a plurality of addressing schemes, e.g. with both IPv4 and IPv6 · CPC title