IP Library Granted Patent US 12695642
Granted Patent B2
US 12695642 · App. 18/628,877 · Granted Jul 28, 2026

Fast recovery in layer 2 rings using selective replication

Inventors: Saravanan M Karunanidhi (Bangalore, IN); Sonal Shah (Bengaluru, IN)
Assignee: Cisco Technology, Inc.
H04L12/437H04L45/24H04L45/745
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Quick Facts
Patent No.
US 12695642
App. No.
18/628,877
Filed
Apr 8, 2024
Granted
Jul 28, 2026
Kind
B2
Art Unit
2463
USPC
370/223
Abstract

In one embodiment, fast recovery in layer 2 rings using selective replication is disclosed. A method includes configuring, at a ring node of a network ring, a lookup table of the ring node to point to both a first ring port and a second ring port of the ring node for remote addresses learned on either the first ring port or the second ring port and configuring, at the ring node, the lookup table to point to a corresponding non-ring port of the ring node for local addresses learned on that corresponding non-ring port. The method further includes receiving, at the ring node, a packet having a destination address and sending, by the ring node, the packet toward the destination address according to the lookup table, thereby replicating the packet, when received on a non-ring port of the ring node and destined to a remote address, onto both the first ring port and the second ring port.

Claims (49)

1 . A method, comprising:

configuring, at a ring node of a network ring, a lookup table of the ring node to point to both a first ring port and a second ring port of the ring node for remote addresses learned on either the first ring port or the second ring port;

configuring, at the ring node, the lookup table to point to a corresponding non-ring port of the ring node for local addresses learned on that corresponding non-ring port;

receiving, at the ring node, a packet having a destination address; and

sending, by the ring node, the packet toward the destination address according to the lookup table, thereby replicating the packet, when received on a non-ring port of the ring node and destined to a remote address, onto both the first ring port and the second ring port.

2 . The method of claim 1 , wherein the packet is received on one of the first ring port or the second ring port and is destined to a remote address, and wherein sending comprises:

transiting the packet to another of the first ring port or the second ring port according to the lookup table.

3 . The method of claim 2 , wherein the packet is prevented from being sent out a same port that received the packet despite the lookup table.

4 . The method of claim 1 , wherein the packet is received on one of the first ring port or the second ring port and is destined to a local address, and wherein sending comprises:

passing the packet only onto an appropriate non-ring port of the ring node.

5 . The method of claim 1 , further comprising:

detecting a link failure in the network ring; and

refraining from communicating the link failure to switches associated with the network ring.

6 . The method of claim 1 , further comprising:

detecting a link failure in the network ring; and

refraining from purging one or more of the remote addresses learned on either the first ring port or the second ring port in response to the link failure.

7 . The method of claim 1 , further comprising:

detecting a link failure in the network ring based on a beacon interval sent across the network ring.

8 . The method of claim 1 , further comprising:

providing, to the network ring, a convergence time of less than ten milliseconds when a link failure is detected in the network ring.

9 . The method of claim 1 , wherein the network ring comprises a layer 2 ring network.

10 . The method of claim 1 , wherein the packet is an Internet of Things (IoT) packet.

11 . An apparatus, comprising:

one or more network interfaces to communicate with a network as a ring node of a network ring;

a processor coupled to the one or more network interfaces and configured to execute one or more processes; and

a memory configured to store a process that is executable by the processor, the process, when executed, configured to:

configure a lookup table of the ring node to point to both a first ring port and a second ring port of the ring node for remote addresses learned on either the first ring port or the second ring port;

configure the lookup table to point to a corresponding non-ring port of the ring node for local addresses learned on that corresponding non-ring port;

receive a packet having a destination address; and

send the packet toward the destination address according to the lookup table, thereby replicating the packet, when received on a non-ring port of the ring node and destined to a remote address, onto both the first ring port and the second ring port.

12 . The apparatus of claim 11 , wherein the packet is received on one of the first ring port or the second ring port and is destined to a remote address, and wherein the process is configured to send the packet by transiting the packet to another of the first ring port or the second ring port according to the lookup table.

13 . The apparatus of claim 12 , wherein the packet is prevented from being sent out a same port that received the packet despite the lookup table.

14 . The apparatus of claim 11 , wherein the packet is received on one of the first ring port or the second ring port and is destined to a local address, and wherein the process is configured to send the packet by passing the packet only onto an appropriate non-ring port of the ring node.

15 . The apparatus of claim 11 , wherein the process, when executed, is configured to:

detect a link failure in the network ring; and

refrain from communicating the link failure to switches associated with a network ring.

16 . The apparatus of claim 11 , wherein the process, when executed, is configured to:

detect a link failure in the network ring; and

refrain from purging one or more of the remote addresses learned on either the first ring port or the second ring port in response to the link failure.

17 . The apparatus of claim 11 , wherein the process, when executed, is configured to:

detect a link failure in a network ring based on a beacon interval sent across the network ring.

18 . The apparatus of claim 11 , wherein the process, when executed, is configured to:

provide a convergence time of less than five milliseconds when a link failure is detected in a network ring.

19 . The apparatus of claim 11 , wherein the network ring comprises a layer 2 ring network.

20 . A tangible, non-transitory, computer-readable medium storing program instructions that cause a device to execute a process comprising:

configuring, at a ring node of a network ring, a lookup table of the ring node to point to both a first ring port and a second ring port of the ring node for remote addresses learned on either the first ring port or the second ring port;

configuring, at the ring node, the lookup table to point to a corresponding non-ring port of the ring node for local addresses learned on that corresponding non-ring port;

receiving, at the ring node, a packet having a destination address; and

sending, by the ring node, the packet toward the destination address according to the lookup table, thereby replicating the packet, when received on a non-ring port of the ring node and destined to a remote address, onto both the first ring port and the second ring port.