US-20260128941-A1 - FALLBACK MECHANISM TO MINIMIZE SERVICE DISRUPTION IN RING TOPOLOGY BASED ON NODE UNAVAILABILITY

US20260128941A1US 20260128941 A1US20260128941 A1US 20260128941A1US-20260128941-A1

Abstract

Disclosed are systems, apparatuses, and methods to minimize service disruption in ring topology based on unavailability of the network device. A network device includes a network interface configured to receive frames from other network devices in a ring network and configured to detect that the network device will become unavailable and, in response to detecting the network device will become unavailable, transmit an unavailability frame to a first network device in the ring network and a second network device in the ring network. The unavailability frame indicates that the network device will become unavailable and causes at least one of the first network device or the second network device to change a transmission direction in the ring network. The unavailability frame is configured and stored in a hardware to reduce the power required to transmit the unavailability frame.

Inventors

Ashok Hegde
Srinivasa Rao NALLURI
Robert Edgar Barton
Saravanan M Karunanidhi

Assignees

CISCO TECHNOLOGY, INC.

Dates

Publication Date: 20260507
Application Date: 20241106

Claims (20)

1 . A method, comprising: detecting that a network device configured in a ring network will become unavailable; and transmitting an unavailability frame to a first network device in the ring network and a second network device in the ring network, wherein the unavailability frame indicates that the network device will become unavailable, and wherein the unavailability frame causes at least one of the first network device or the second network device to change a transmission direction in the ring network.
2 . The method of claim 1 , wherein the unavailability frame is received by a supervisor node, wherein the unavailability frame reactivates a deactivated link in the ring network that excludes the network device in a transmission path.
3 . The method of claim 1 , wherein detecting that the network device configured in the ring network will become unavailable comprises: detecting a loss of a power source; and switching power supply to a backup power source that provides sufficient power to the network device to transmit the unavailability frame.
4 . The method of claim 1 , wherein the first network device and the second network device are configured to detect the unavailability frame in a hardware component and reconfigure network configuration in response to the unavailability frame.
5 . The method of claim 1 , wherein the unavailability frame is preconfigured and stored in a hardware component.
6 . The method of claim 1 , wherein the unavailability frame includes an identification of the network device and a reason that identifies why the network device is unavailable.
7 . The method of claim 6 , wherein the identification of the network device and the reason are included in a type length value (TLV) field.
8 . The method of claim 1 , wherein the first network device and the second network device are reconfigured before a fallback power supply of the network device falls below a shutdown threshold of power.
9 . The method of claim 1 , wherein the network device further comprises a fallback power supply for providing power during a last gasp period.
10 . The method of claim 9 , wherein the network device further comprises a fallback detector for detecting a power supply failure.
11 . A network device for minimizing service disruption in ring topology based on unavailability of the network device, comprising: a network interface configured to receive frames from other network devices in a ring network and including a frame processing circuit for processing frames and configured to: detect that the network device will become unavailable; and in response to detecting the network device will become unavailable, transmit an unavailability frame to a first network device in the ring network and a second network device in the ring network, wherein the unavailability frame indicates that the network device will become unavailable; wherein the unavailability frame causes at least one of the first network device or the second network device to change a transmission direction in the ring network.
12 . The network device of claim 11 , wherein the unavailability frame is received by a supervisor node, wherein the unavailability frame reactivates a deactivated link in the ring network that excludes the network device in a transmission path.
13 . The network device of claim 11 , further comprising a fallback detector configured to: detect a loss of a power source; and switch power supply to a backup power source that provides sufficient power to the network device to transmit the unavailability frame.
14 . The network device of claim 11 , wherein the first network device and the second network device are configured to detect the unavailability frame in a hardware component and reconfigure network configuration in response to the unavailability frame.
15 . The network device of claim 11 , wherein the unavailability frame is preconfigured and stored in a network interface.
16 . The network device of claim 11 , wherein the unavailability frame includes an identification of the network device and a reason that identifies why the network device is unavailable.
17 . The network device of claim 16 , wherein the identification of the network device and the reason are included in a type length value (TLV) field.
18 . The network device of claim 11 , wherein the first network device and the second network device are reconfigured before a fallback power supply of the network device falls below a shutdown threshold of power.
19 . The network device of claim 11 , wherein the network device further comprises a fallback power supply configured to provide power during a last gasp period.
20 . The network device of claim 19 , wherein the network device shuts down at least one extra component of the network device during the last gasp period.

Description

TECHNICAL FIELD The disclosure relates generally to Layer 2 networks and, more specifically but not exclusively, to a fallback mechanism to minimize service disruption in ring topology based on node unavailability. BACKGROUND Ring network topologies are commonly utilized in Layer 2 networks, which operate at the Data Link Layer of the OSI model, to ensure reliable data transmission across physical network links. In a ring network, each node is connected in a circular pathway, with data typically traveling in a single direction through the network. Such configurations are particularly advantageous in high-speed network environments, including Fiber Distributed Data Interface (FDDI) networks, industrial automation, utility infrastructures, and broadcasting systems, where consistent and predictable data flow is critical. The dual-attached nodes within a ring network can be configured to transmit data in a single direction, with the option to enable bidirectional communication through the closure of a network switch. In such a topology, when one node within the ring fails, a fallback process can occur that enables a deactivated link to establish a backup path. The fallback process can take time, especially in larger networks with more nodes, and create temporary delays as the network protocols determine the new path for data transmission for each of the nodes. The need to reroute data around the disruption can introduce additional latency and may interrupt sensitive operations in the network. BRIEF DESCRIPTION OF THE DRAWINGS In order to describe the manner in which the above-recited and other advantages and features of the disclosure may be obtained, a more particular description of the principles briefly described above will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings. Understanding that these drawings depict only exemplary embodiments of the disclosure and are not therefore to be considered to be limiting of its scope, the principles herein are described and explained with additional specificity and detail through the use of the accompanying drawings in which: FIG. 1 illustrates an example of a ring network topology. FIG. 2 is a block diagram illustrating a network device 200 including a fallback mechanism to minimize service disruption in ring topology based on node unavailability in accordance with some aspects of the disclosure. FIG. 3 is a sequence diagram illustrating a fallback mechanism to minimize service disruption in ring topology based on node unavailability in accordance with some aspects of the disclosure. FIG. 4 illustrates an example method for minimizing service disruption in ring topology based on node unavailability in accordance with some aspects of the disclosure. FIG. 5 illustrates a block diagram of a system-on-chip (SoC) used in a network device to perform various functions in hardware in accordance with various aspects of the disclosure. FIG. 6 shows an example of a computing system, which may be for example any computing device that may implement components of the system. DESCRIPTION Overview According to one aspect, a network device is provided to minimize service disruption in ring topology based on unavailability of the network device. A network device includes a network interface configured to receive frames from other network devices in a ring network and configured to detect that the network device will become unavailable and, in response to detecting the network device will become unavailable, transmit an unavailability frame to a first network device in the ring network and a second network device in the ring network. The unavailability frame indicates that the network device will become unavailable and causes at least one of the first network device or the second network device to change a transmission direction in the ring network. The unavailability frame is configured and stored in hardware. The network device does not need to use any extra processing, interrupts, and delays associated with software (e.g., scheduling) and reduces the power required to transmit the unavailability frame. In one aspect, the network device includes a fallback detector configured to detect a loss of a power source. The fallback detector may switch power supply to a backup power source that provides sufficient power to the network device to transmit the unavailability frame. The backup power source (or fallback power source) may include a battery, a capacitor, or capacitors, that store enough power to transmit the unavailability frame and maintain the network device in a powered state until a supervisor node within the ring network reconfigures the network transmission associated with the ring network. In some cases, a switch can be activated that is disabled and prevents collisions, duplicated traffic, and other network challenges with bidirectional paths. The supervisor node may activate the switch and reconfigure network nodes befor