IP Library › Granted Patent US 12701074
Granted Patent B2
US 12701074 · App. 18/731,632 · Granted Aug 4, 2026

Loop avoidance communications method, device, and system

Inventors: Chongyang Hu (Beijing, CN); Haibo Wang (Beijing, CN)
Assignee: HUAWEI TECHNOLOGIES CO., LTD.
H04L45/18H04L45/28H04L45/741H04L45/745H04L2101/622
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Quick Facts
Patent No.
US 12701074
App. No.
18/731,632
Granted
Aug 4, 2026
Kind
B2
Abstract

In a loop avoidance communications method, a first provider edge (PE) device sends a first identifier to a second PE device through a first interface; the first PE device receives, from the second PE through the first interface, a data packet including the first identifier. Then, the first PE device determines that a second interface associated with the first identifier is in a faulty state. In response to determining that the second interface is in the faulty state, the first PE device avoids sending the data packet to the second PE device through the first interface. The first PE device connects to a customer edge (CE) device using the second interface.

Claims (45)

1 . A communications method implemented by a first provider edge (PE) device and comprising:

sending a segment identifier (SID) to a second PE device, wherein an operation associated with the SID comprises forwarding a data packet through a second interface of the first PE device, wherein the first PE device and the second PE device are connected to a customer edge (CE) device in an all-active mode, wherein the first PE device is connected to the CE device through the second interface, and wherein the first PE device is connected to the second PE device through a first interface of the first PE device;

receiving the data packet from the second PE device via the first interface, wherein the data packet comprises a destination address that is the SID; and

avoiding sending the data packet via the first interface when the second interface is in a faulty state.

2 . The communications method of claim 1 , further comprising storing an entry comprising the SID and a second identifier of the second interface, wherein the entry does not comprise a first identifier of the first interface.

3 . The communications method of claim 1 , further comprising discarding the data packet when the second interface is in the faulty state.

4 . The communications method of claim 1 , wherein the first PE device is in a Segment Routing over Internet Protocol version 6 (SRv6) Ethernet virtual private network (EVPN).

5 . The communications method of claim 1 , wherein sending the SID to the second PE device comprises sending, to the second PE device, a routing message comprising the SID.

6 . The communications method of claim 5 , wherein the routing message is a Border Gateway Protocol (BGP) message comprising an attribute, and wherein the attribute comprises the SID.

7 . The communications method of claim 6 , wherein the attribute is a Segment Routing over Internet Protocol version 6 (SRv6) virtual private network (VPN) SID attribute.

8 . The communication method of claim 6 , wherein the BGP message advertises an Ethernet auto-discovery (A-D) route.

9 . The communications method of claim 6 , wherein the attribute instructs the second PE device to add the SID to the data packet when sending the data packet to the first PE device.

10 . The communications method of claim 1 , wherein the SID is a Segment Routing over Internet Protocol version 6 (SRv6) SID.

11 . The communications method of claim 10 , wherein the SRv6 SID is associated with an Ethernet virtual private line (EVPL) service on the first PE device.

12 . The communications method of claim 10 , wherein the SID is an End.DX2L SID.

13 . The communications method of claim 12 , wherein a function of the End.DX2L SID is associated with forwarding the data packet through a local outbound interface associated with the SID.

14 . The communications method of claim 1 , wherein the SID is an End.DT2UL SID.

15 . The communications method of claim 14 , wherein a function of the End.DT2UL SID is associated with forwarding the data packet through a local interface in an entry.

16 . The communications method of claim 1 , wherein a function of the SID is:

forwarding the data packet or another data packet through an outbound interface associated with the SID; or

forwarding the data packet or another data packet through a local interface in an entry that matches a destination medium access control (MAC) address.

17 . A first provider edge (PE) device comprising:

a first interface configured to connect to a second PE device;

a second interface configured to connect to a customer edge (CE) device that is multi-homed to the first PE device and the second PE device in an all-active mode, wherein an operation associated with a segment identifier (SID) comprises forwarding a data packet through the second interface; and

a processor coupled to the first interface and the second interface and configured to:

send the SID to the second PE device;

receive the data packet from the second PE device via the first interface, wherein the data packet comprises a destination address that is the SID; and

avoid sending the data packet via the first interface when the second interface is in a faulty state.

18 . The first PE device of claim 17 , wherein the processor is further configured to store an entry comprising the SID and a second identifier of the second interface, and wherein the entry does not comprise a first identifier of the first interface.

19 . The first PE device of claim 17 , wherein the processor is further configured to discard the data packet when the second interface is in the faulty state.

20 . The first PE device of claim 17 , wherein the first PE device is in a Segment Routing over Internet Protocol version 6 (SRv6) Ethernet virtual private network (EVPN).

21 . The first PE device of claim 17 , wherein the processor is further configured to further send the SID to the second PE device by sending a Border Gateway Protocol (BGP) message comprising an attribute, and wherein the attribute comprises the SID.

22 . The first PE device of claim 21 , wherein the attribute is a Segment Routing over Internet Protocol version 6 (SRv6) virtual private network (VPN) SID attribute.

23 . The first PE device of claim 17 , wherein the SID is a Segment Routing over Internet Protocol version 6 (SRv6) SID.

24 . A communications system comprising:

a second provider edge (PE) device; and

a first PE device comprising a first interface and a second interface and configured to:

connect via the second interface to a customer edge (CE) device that is multi-homed to the first PE device and the second PE device in an all-active mode;

connect to the second PE device via the first interface;

send a segment routing (SID) to the second PE device, wherein an operation associated with the SID comprises forwarding a data packet through the second interface;

receive the data packet from the second PE device and via the first interface, wherein the data packet comprises a destination address that is the SID; and

avoid sending the data packet via the first interface when the second interface is in a faulty state,

wherein the second PE device is configured to:

receive the SID from the first PE device; and

send the data packet to the first PE device via the first interface.