Near-hitless upgrade or fast bootup with mobile virtualized hardware

An embodiment is directed to switchover operations with a mobile virtualized network device in a mobile device. The mobile virtualized hardware switchover operations may be used to selectively and temporarily provide virtualized control-plane operations to the data-plane of a non-redundant network device undergoing an upgrade or a reboot of its control plane. A non-redundant network device may operate hitless, or near hitless, operation even when its control plane is unavailable.

TECHNICAL FIELD

Embodiments of the present invention relate to networking equipment, in particular, hardware and software architecture and components that provide a virtualized switch in switchover operations. ss

BACKGROUND

Modern networking devices such as switches are configured with a data plane (also referred to as the forwarding plane), a control plane, and a management plane.

The data or forwarding plane comprises an amalgamation of hardware and software components responsible for the routing of packets from one port of the device to another port and are optimized for speed, simplicity, and regularity. The data plane relies on routing and/or forwarding tables that are maintained in high-speed, often customized, memory or tables. In most implementations, data plane components typically include processors that interface with application-specific integrated circuits (ASICs) and high-speed memory across dedicated data buses or switch fabrics.

The control plane operates with the data plane and is primarily responsible for the populating and updating of the routing or forwarding tables, among other things. Control plane hardware components are typically optimized for customizability, handling policies and exceptions, and are often implemented via microprocessor(s) (often referred to as a host processor(s)) that implement instructions stored in local memory.

During software upgrade operation, particularly for non-redundant switches, the upgrade operation involves bringing down the control plane so the operating system or application executing in that operating space can be updated. While the data-plane can be left running, without the control plane, the routing and forwarding information in the data-plane and protocol state machine changes in the control plane can become stale or lost. Redundant equipment, which has its own independent set of data-plane and control-plane components, are often used in switchover operations to completely take over the role of the upgrading device.

DESCRIPTION OF THE EXAMPLE EMBODIMENTS

Overview

In an aspect, an embodiment of the present disclosure is directed to switchover operations (also referred to as virtualized or mobile virtualized hardware switchover operations) with a virtualized or mobile virtualized network device (also referred to herein as a virtualized standby switch or a mobile virtualized network device) in a cloud or remote infrastructure or a mobile computing device.

The mobile computing device is configured to execute an image comprising operating-system and application-processes of an enterprise/access switch. The mobile computing device further includes “stub” function modules or simulation modules for certain components of the operating-system and application-processes. The mobile computing device may all of the HA/ISSU/SSO capability, and hence, the process of forming of a stack is equivalent as with a second physical switch.

The term “mobile computing device” as used herein refers to a laptop, tablet, small compact-factor single board computers, mini-PC, stick PC, and the like, that can be configured with control-plane processes and stub/simulated modules to execute mobile virtualized hardware switchover operations. The virtualized or mobile virtualized hardware switchover operations may be used to selectively and temporarily provide virtualized control-plane operations to the data-plane of a non-redundant network device undergoing an upgrade or a reboot of its control plane. To this end, the non-redundant network device can maintain hitless, or near hitless, operation for its data plane even when its control plane is unavailable. The term “selectively” is used herein to refer to the selective use of the virtualized or mobile virtualized hardware as a proxy of the control plane of the active network device and not that of the data-plane. The term ‘temporarily” is used herein to refer to the limited duration that the virtualized hardware is used (e.g., for virtualized hardware switchover operations), though, in some embodiments, it is contemplated that the virtualized hardware and techniques described herein can be used in an on-going manner, say, to augment the processing power of the control plane of the active network device.

The term “control plane” is a general term that is used to refer to group of functions and packets that involve configuration, protocol state-machine, state of the switch etc. and usually implemented in the host processor of the switch. Examples of such traffic may include Spanning Tree Protocol (STP), Hot Standby Router Protocol (HSRP), and control packets that are destined to the switch, or sent from the switch or application layer protocols such as Secure Shell (SSH) and Simple Network Management Protocol (SNMP) that must be handled by the host processor.

During the virtualized or mobile virtualized hardware switchover operation, in some embodiments, a mobile network device is initialized and/or connected to the non-redundant network device to synchronize its control-plane states to the non-redundant network device (also referred to herein as the “active network device” or “active switch” in switchover lexicon). For a virtualized or mobile virtualized hardware switchover operation, the virtualized instance of the control plane of the non-redundant switch is dynamically created in the cloud or remote infrastructure. The states between the virtualized or mobile virtualized hardware and the physical hardware may be synchronized using synchronization operation used in high availability (HA) operations, such as In-Service Software Upgrade (ISSU) operations and/or Stateful Switchover (SSO) operations. A virtual transport layer (e.g., implemented by a control-plane data-plane interface transport module, also referred to herein as a “virtual PCI” or “VPCI module”) may be executed in each of the active network device and in the virtualized or mobile virtualized network device, at the respective edge of the data-plane and control-plane, to transport bus transactions, e.g., associated with control-plane updates, from the data plane of the active network device to the control plane of the virtualized network device over a network tunnel, and vice versa. Stated differently, virtual transport layer can be characterized as a data-plane access interface or virtual DP access interface. In addition, rather than PCI, other access interface may be used as discussed herein, include AXI interface, and etc. That is, the control-plane data-plane interface transport module also transports bus transactions, e.g., associated with data-plane updates, from the control plane of the virtualized network or mobile virtualized device and the data plane of the active network device over a network tunnel to update the data-plane.

In some embodiments, the virtualized network device is instantiated in cloud or remote infrastructure (e.g., cloud servers or private servers). In other embodiments, rather than cloud or remote infrastructure, the virtualized mobile hardware switchover operation is executed with a local computing device, e.g., mobile or portable devices, e.g., laptop, iPad, and the like. In each of these embodiments, indeed, the virtualized or mobile virtualized network device does not require its own data-plane components, and only need to have the computing capability to manage the control-plane of the active network device. In some embodiments, the virtualized or mobile virtualized network device may be implemented across multiple cores or processing unit, e.g., using hyperthreading capabilities.

Notably, the virtualized or mobile virtualized network device may be configured with the same or compatible computer readable instructions associated with the system image (e.g., comprising the operating system and routing application) as that of the active network device. To this end, the transactions received at the bus interconnect to update data plane tables and associated states can be performed by virtualized network device using the same or compatible system image. The modularity ensures that virtualized or mobile virtualized hardware switchover operation, in some embodiments, can be performed for any system image as generated through current development processes and workflow without need for customization or modification of the system image for it be used for this purpose. In some embodiments, the software image and control-plane can be run on top of a virtual machine (VM) or virtual host, e.g., based on virtualization or containerization technology, which are used interchangeably herein.

In maintaining hitless, or near hit-less control-plane, for non-redundant network devices (e.g., non-redundant switches), security enhancements and bug fixes and other updates can be applied to non-redundant network devices, e.g., that are in critical infrastructure, such as for real-time controls in factory automation, without need for local redundant hardware. In some instances, reducing disruption time during minor upgrades to a few seconds can be the difference between having an uptime or a downtime for the factory automation application, particularly, where factory automation application have failsafe timeout operations to ensure proper synchronization of its real-time agents. Having these minor upgrades (as well as major ones) performed at higher frequency would thus improve the overall system health and security of the underlying network and the overall platform.

In an aspect, a network device is disclosed that is configured as a mobile virtualized standby switch, the network device comprising a processor executing instructions for control-plane operations that manage and maintain a plurality of data-plane-associated tables of a switch-fabric of a data plane of a second network device; a network interface; a memory having computer readable instructions, wherein execution of the computer readable instruction, cause the processor to: establish, via the network interface, a network connection with the second network device, wherein the second network device comprises one or more host processors executing a control-plane that manage and maintain the plurality of data-plane-associated tables; synchronize control-plane states of the network device configured as a mobile virtualized standby switch with control-plane states of the control plane of the second network device; and upon receipt of a switchover command, update status of the network device from a standby device to an active device; determine, via control-plane operations, updates to a portion of the plurality of data-plane-associated tables; and transport, over the network connection, to the second network device, the determined updates to the portion of the plurality of data-plane-associated tables of the data-plane of the second network device when the control plane of the second network device is unavailable.

In some embodiments, the network device further includes a bus-interconnect transport module, the bus-interconnect transport module being configured, by computer instructions, to obtain a control-plane update packet received over the network connection from the second network device, where in the control-plane update packet comprises control-plane bus-interconnect transaction read by a second bus-interconnect transport module executing at the second network device following receipt of a control-plane packet received at the data plane of the second network device; write a first set of bus-interconnect transactions to a bus interconnect of the network device based on the received control-plane update packet; read a second set of bus-interconnect transactions from the bus interconnect of the network device; encapsulate a payload comprising the second set of bus-interconnect transactions in a data-plane update message; and transmit, over the network connection, data-plane update packet to the second network device, wherein the second bus-interconnect transport module of the second network device is configured to receive the decapsulate the data-plane update packet and write the second set of bus-interconnect transactions to the bus interconnect to the second network device to update the data-plane-associated tables of the data plane of the second network device.

In some embodiments, the network device is selected from the group consisting of a laptop computing device, a tablet computing device, a single-board computer (SBC) computing device (e.g., Raspberry Pi, PC-on-a-stick), and a smartphone computing device.

In some embodiments, the computer readable instructions comprise instructions for one or more stub application modules of a non-control-plane associated operations, wherein each of the one or more stub application modules is configured to provide stimulated valid return calls for the non-control-plane associated operations.

In some embodiments, the non-control-plane associated operations is selected from the group consisting of an operating system associated module or process; and a switch application associated module or process.

In some embodiments, the computer readable instructions to synchronize the control-plane states of the virtualized standby switch with the control-plane states of the network device comprises instructions for switchover operations with a physical switch.

In some embodiments, the control-plane associated message comprises protocol state machine updates.

In some embodiments, the second network device comprises a non-redundant stackable switch.

In some embodiments, the network device as the mobile virtualized standby switch provides near-hitless operation of the second network device while the host processor is unavailable during an upgrade or boot-up process.

In some embodiments, the synchronization operation is performed using at least one of high availability (HA) operations, In-Service Software Upgrade (ISSU) operations, and Stateful Switchover (SSO) operations.

In some embodiments, the mobile virtualized standby switch is configured synchronize with the control-plane states of the second network device over a period of a few hours.

In some embodiments, the update of the one or more of the plurality of data-plane-associated tables and states of the second network device includes: updates associated with newly learnt MAC entries; updates associated with Layer 3 entries; updates associated with EtherChannel membership; updates associated with Spanning Tree Protocol topology-change; updates associated with protocol state or resource state change; or updates associated with hardware resource transition change.

In some embodiments, the network connection comprises a front-side interchassis system link of the second network device.

In some embodiments, the network connection comprises a back-side interchassis system link of the second network device that connects to a communication link across an adapter.

In some embodiments, the computer readable instructions includes instructions to synchronize the control-plane states of the network device with the control-plane states of the virtualized standby switch after the host processor boot-ups with the new system image.

In another aspect, a method is disclosed to upgrade a non-redundant stackable switch, the method comprising: establishing, via a network interface of a mobile computing device, a network connection with the non-redundant stackable switch, wherein the non-redundant stackable switch comprises one or more host processors executing a control-plane that manage and maintain the plurality of data-plane-associated tables; synchronizing control-plane states of the mobile network device configured as a mobile virtualized standby switch with control-plane states of the control plane of the non-redundant stackable switch; and upon receipt of a switchover command, updating status of the mobile computing device from a standby device to an active device; determining, via control-plane operations, updates to a portion of the plurality of data-plane-associated tables; and transporting, over the network connection, to the non-redundant stackable switch, the determined updates to the portion of the plurality of data-plane-associated tables of the data-plane of the mobile computing device when the control plane of the mobile computing device is unavailable.

In some embodiments, the method further includes obtaining, at a first bus-interconnect transport module executing at the mobile computing device, a control-plane update packet received over the network connection from the non-redundant stackable switch, where in the control-plane update packet comprises control-plane bus-interconnect transaction read by a second bus-interconnect transport module executing at the non-redundant stackable switch following receipt of a control-plane packet received at the data plane of the non-redundant stackable switch; writing, by the first bus-interconnect transport module, a first set of bus-interconnect transactions to a bus interconnect of the mobile computing device based on the received control-plane update packet; reading, by the first bus-interconnect transport module, a second set of bus-interconnect transactions from the bus interconnect of the mobile computing device; encapsulating, by the first bus-interconnect transport module, a payload comprising the second set of bus-interconnect transactions in a data-plane update message; and transmitting, from the mobile network device, over the network connection, data-plane update packet to the non-redundant stackable switch, wherein the second bus-interconnect transport module of the non-redundant stackable switch is configured to receive the decapsulate the data-plane update packet and write the second set of bus-interconnect transactions to the bus interconnect to the non-redundant stackable switch to update the data-plane-associated tables of the data plane of the non-redundant stackable switch.

In some embodiments, the update of the one or more of the plurality of data-plane-associated tables and states of the stackable switch includes: updates associated with newly learnt MAC entries; updates associated with Layer 3 entries; updates associated with EtherChannel membership; updates associated with Spanning Tree Protocol topology-change; updates associated with protocol state or resource state change; or updates associated with hardware resource transition change, and wherein the mobile virtualized standby switch is configured to provide near-hitless operation of the network switch while the host processor is unavailable during the upgrade or boot-up process.

In another aspect, a non-transitory computer readable medium is disclosed comprising computer readable instructions, wherein execution of the computer readable instruction by a processor of a network device, cause the processor to: obtain a control-plane update packet received over the network connection from the non-redundant stackable switch, where in the control-plane update packet comprises control-plane bus-interconnect transaction read by a second bus-interconnect transport module executing at the non-redundant stackable switch following receipt of a control-plane packet received at the data plane of the non-redundant stackable switch; write a first set of bus-interconnect transactions to a bus interconnect of the mobile computing device based on the received control-plane update packet; read a second set of bus-interconnect transactions from the bus interconnect of the mobile computing device; encapsulate a payload comprising the second set of bus-interconnect transactions in a data-plane update message; and transmit, over the network connection, data-plane update packet to the non-redundant stackable, wherein the second bus-interconnect transport module of the non-redundant stackable is configured to receive the decapsulate the data-plane update packet and write the second set of bus-interconnect transactions to the bus interconnect to the non-redundant stackable to update the data-plane-associated tables of the data plane of the non-redundant stackable.

In some embodiments, the computer readable instructions, when executed by the processor, further cause the processor to: obtain a control-plane update packet received over the network connection from the second network device, where in the control-plane update packet comprises control-plane bus-interconnect transaction read by a second bus-interconnect transport module executing at the second network device following receipt of a control-plane packet received at the data plane of the second network device; write a first set of bus-interconnect transactions to a bus interconnect of the network device based on the received control-plane update packet; read a second set of bus-interconnect transactions from the bus interconnect of the network device; encapsulate a payload comprising the second set of bus-interconnect transactions in a data-plane update message; and transmit, over the network connection, data-plane update packet to the second network device, wherein the second bus-interconnect transport module of the second network device is configured to receive the decapsulate the data-plane update packet and write the second set of bus-interconnect transactions to the bus interconnect to the second network device to update the data-plane-associated tables of the data plane of the second network device.

In another aspect, a network device (e.g., non-redundant stackable or non-stackable switch) comprising a host processor executing instructions for control-plane operations that manage and maintain a plurality of data-plane-associated tables of a switch-fabric of the network device; a network interface (native or plug-able); a memory having computer readable instructions, wherein execution of the computer readable instruction, causes the host processor to establish, via the network interface, a network connection (e.g., a tunnel or an inter-chassis link) with a remote computing device comprising a remote processor; direct the remote computing device to instantiate a virtualized standby switch (e.g., on a virtual machine or a container), wherein the instantiated virtualized standby switch is configured to execute a set of instructions, to manage and maintain the plurality of data-plane-associated tables of the switch-fabric of the network device; synchronize control-plane states of the virtualized standby switch with control-plane states of the network device; and reset the host processor to boot-up with a new system image in an upgrade or boot-up process, wherein during the upgrade process, the virtualized standby switch is configured to update, via data-plane transaction messages over the network interface, one or more of the plurality of data-plane-associated tables (e.g., L2 MAC table, MAC learning tables, L3 tables, FIB, etc.), and states of the network device. In some embodiments, the set of instructions for the control plane operation is the same as that of the network device (e.g., same version). In other embodiments, the set of instructions for the control operation is different, but functionally the same or compatible, from that of the network device (e.g., different version). That is, the image that runs on physical hardware and the virtual switch are derived, in some embodiments, from the same code base, but the image is different. Also, in case of image upgrade/downgrade, it will be a different version of the code, and could have substantial differences.

The term “host processor”, as used herein, is used interchangeably with the term “host CPU” and generally refers to cores of a microprocessor or microcontroller, e.g., having RISC or CISC architecture, of a device of interest, e.g., of an active network device (e.g., switch), that are configured to execute computer instructions within the framework of an operating system in a networking device.

The term “remote processor”, as used herein, is used interchangeably with the term “remote CPU” and generally also refers to cores of a microprocessor or microcontroller, e.g., having RISC or CISC architecture, of a remote or cloud server or network device, that are configured to execute computer instructions within a virtualization or container framework of the remote or cloud server. The remote processor is configured to execute, e.g., via a virtualized hardware switchover operation, the control plane of the active network device to serve as a proxy control plane for the active network device when it is unavailable.

The term “stackable switch” refers to a network switch that is fully functional when operating as a standalone device, but which can also be set up to cooperatively operate together with one or more other network switches as a group in which the group can be configured to show the characteristics of a single switch. Indeed, the stack may have a common set of one or more IP addresses for remote administration of the stack as a whole. Stackable switches, and similar class device, can provide redundant operations to individual switches in switchover operations. Non-stackable switches also refer to switches configured to operate as a standalone device. Stackable and non-stackable switches may be configured with modules to perform virtualized hardware switchover operations as described herein.

The term “switchover” generally refers to the manual or automatically triggered) switching of operation from one network device to a redundant or standby network device (e.g., for failure of a control-plane process but is used in the instant embodiments to perform system maintenance, such as installing patches, and upgrading software. Virtualized hardware switchover operation as described herein, in contrast, refers to the switching of control-plane operations from the active network device to a virtualized network device where the data plane operation continues to operate at the active network device. Virtualized hardware switchover operation, preferably, relies on conventional or existing switchover mechanisms and programs to perform the various hand-shaking operations and the synchronization of control-plane states. These switchover mechanisms are coupled with other operations described herein to perform the virtualized hardware switchover operation, including virtualization mechanisms, cloud infrastructure, or bus interconnect transport mechanisms, among others.

The term “data-plane” generally encompasses data-plane processor(s) and data-plane resource(s) configured to route packets from one port of a network device to another port. Data-plane processor (also referred to herein as data-plane devices) can include processing units involved in the switching or routing of packets in the network device such as network processors (NPUs), switching-ASICs (application-specific integrated circuit), switching FPGA (field-programmable gate array), CPLD (complex programmable logic device), and the like. Examples of data-plane resources may include, but are not limited to, MAC address table(s), FIB table(s), ACL table(s), and any other tables, register contents, content address memory (CAM) contents, tertiary content address memory (TCAM) contents, binary content-addressable memory (BCAM) contents, and memory contents (e.g., non-persistent, volatile, etc.) maintained or used by data-plane processors.

In some embodiments, the network device includes a second processor unit or upgrade logic circuit (i.e., a non-host CPU component, e.g., logic circuits of NPU, RP, ASIC, switching-FPGA, or a core located therein or an auxiliary processor) (e.g., implementing a PCI transport module, also referred to herein as a VPCI module) configured to: write a first set of bus-interconnect transactions to a bus-interconnect of the network device based on a first set of data-plane transaction messages received from the virtualized standby switch over the network interface, wherein the first set of bus-interconnect transactions updates a portion of the plurality of data-plane-associated tables of the network device (e.g., configure newly learnt MAC entries, update LACP EtherChannel membership); and read a second set of bus-interconnect transactions from the bus interconnect and transmit the second set of bus-interconnect transactions as a second set of data-plane transaction messages to the virtualized standby switch over the network interface, wherein the virtualized standby switch is configured to write a second set of bus-interconnect transactions to the bus interconnect or a host processor, as a logical equivalent of the bus interconnect, of the virtualized standby switch based on the second set of data-plane transaction messages to update control plane states maintained by the virtualized standby switch.

In some embodiments, the computer readable instruction, when executed by the host processor, cause the host processor to establish a tunnel connection (e.g., IP tunnel, GRE tunnel, IPSec tunnel, VXLAN tunnel, etc.) with the virtualized standby switch.

In some embodiments, the computer readable instructions to synchronize the control-plane states of the virtualized standby switch with the control-plane states of the network device comprises instructions for switchover operations with a physical switch.

In some embodiments, the control-plane associated message comprises protocol state machine updates.

In some embodiments, the network device comprises a non-redundant stackable switch.

In some embodiments, the network interface and the second processor unit or upgrade logic circuit is a part of a plug-able module that is connected to a bus-interconnect of the network device.

In some embodiments, the virtualized standby switch provides near-hitless operation of the network switch while the host processor is unavailable during the upgrade or boot-up process.

In some embodiments, the synchronization operation is performed using at least In-Service Software Upgrade (ISSU) operations and Stateful Switchover (SSO) operations, or other high availability (HA) operations.

In some embodiments, the virtualized standby switch is configured to synchronize with the control-plane states of the network device over a finite period (e.g., in a few minutes).

In some embodiments, the network device directs the remote computing device to instantiate the virtualized standby switch by directing the remote computing device to retrieve a system image of the network device from an image server.

In some embodiments, the update of the one or more of the plurality of data-plane-associated tables and states of the network device includes: updates associated with newly learnt MAC entries; updates associated with Layer 3 entries (e.g., IPv4 or IPv6); updates associated with EtherChannel membership; updates associated with Spanning Tree Protocol topology-change; updates associated with protocol state or resource state change; or updates associated with hardware resource transition change.

In some embodiments, the network connection between the active switch and the standby (virtual) switch comprises a front-side inter-chassis system link (e.g., Stackwise Virtual Link (SVL) or the like) of the switch.

In some embodiments, the network connection comprises a back-side inter-chassis system link of the switch that connects to a communication link across an adapter.

In some embodiments, the computer readable instructions includes instructions to synchronize the control-plane states of the network device with the control-plane states of the virtualized standby switch after the host processor boot-ups with the new system image.

In another aspect, a method is disclosed to upgrade a non-redundant stackable switch comprising a host processor executing a system image, the method comprising establishing, via a network interface of the stackable switch, a network connection (e.g., a tunnel) with a remote computing device comprising a remote processor; directing the remote computing device to instantiate a virtualized standby switch (e.g., on a virtual machine or a container), wherein the instantiated virtualized standby switch is configured to execute a set of instructions to manage and maintain the plurality of data-plane-associated tables of the switch-fabric of the network device; synchronizing, over a switchover operation, control-plane states of the virtualized standby switch with control-plane states of the network device; and resetting the host processor to boot-up with a new system image in an upgrade or boot-up process, wherein during the upgrade process, the virtualized standby switch is configured to update, via data-plane transaction messages over the network interface, one or more of the plurality of data-plane-associated tables (e.g., L2 MAC table; MAC learning tables; L3 tables; FIB, etc.), and states of the network device.

In some embodiments, the method includes receiving, over the network interface, a first set of data-plane transaction messages from the virtualized standby switch; writing (e.g., via a vPCI module) a first set of bus-interconnect transactions to a bus-interconnect of the stackable switch based on the received first set of data-plane transaction messages, wherein the first set of bus-interconnect transactions updates a portion of the plurality of data-plane-associated tables of the network device; reading (e.g., via the vPCI module), from the bus interconnect, a second set of bus-interconnect transactions from the data-plane of the stackable switch; and transmitting, to the virtualized standby switch, over the network interface, a second set of data-plane transaction messages generated based on the second set of bus-interconnect transactions, wherein the virtualized standby switch is configured to write a second set of bus-interconnect transactions to the bus interconnect of the virtualized standby switch based on the second set of data-plane transaction messages to update control plane states maintained by the virtualized standby switch.

In some embodiments, the update of the one or more of the plurality of data-plane-associated tables and states of the network device includes: updates associated with newly learnt MAC entries; updates associated with Layer 3 entries (e.g., IPv4 or IPv6); updates associated with EtherChannel membership; updates associated with Spanning Tree Protocol topology-change; updates associated with protocol state or resource state change; or updates associated with hardware resource transition change, and wherein the virtualized standby switch is configured to provide near-hitless operation of the network switch while the host processor is unavailable during the upgrade or boot-up process.

In another aspect, a non-transitory computer readable medium is disclosed comprising computer readable instructions, wherein execution of the computer readable instruction by a processor of a network device, cause the processor to establish, via a network interface of the network device, a network connection (e.g., a tunnel) with a remote computing device comprising a remote processor; direct the remote computing device to instantiate a virtualized standby switch (e.g., on a virtual machine or a container), wherein the instantiated virtualized standby switch is configured to execute a set of instructions to manage and maintain the plurality of data-plane-associated tables of the switch-fabric of the network device; synchronize control-plane states of the virtualized standby switch with control-plane states of the network device; and reset the host processor to boot-up with a new system image in an upgrade or boot-up process, wherein during the upgrade process, the virtualized standby switch is configured to update, via data-plane transaction messages over the network interface, one or more of the plurality of data-plane-associated tables (e.g., L2 MAC table; MAC learning tables; L3 tables; FIB, etc.), and states of the network device.

In some embodiments, the computer readable instructions, when executed by the processor, further cause the processor to: receive, over the network interface, a first set of data-plane transaction messages from the virtualized standby switch; write (e.g., via a vPCI module) a first set of bus-interconnect transactions to a bus-interconnect of the active switch based on the received first set of data-plane transaction messages, wherein the first set of bus-interconnect transactions updates a portion of the plurality of data-plane-associated tables of the network device; read, from the bus interconnect, (e.g., via the vPCI module) a second set of bus-interconnect transactions from the data plane; and transmit, to the virtualized standby switch, over the network interface, a second set of data-plane transaction messages generated based on the second set of bus-interconnect transactions, wherein the virtualized standby switch is configured to write a second set of bus-interconnect transactions to the bus interconnect of the virtualized standby switch based on the second set of data-plane transaction messages to update control plane states maintained by the virtualized standby switch.

Example System

FIGS.1A,1B,1C,2A, and2Beach shows a diagram of an exemplary network device102(shown as active/physical switch102a,102b,102c, and102, respectively) configured to operate with a virtualized or mobile virtualized standby device104(shown as a “virtualized or mobile virtualized standby switch”104a,104b,104c, and104) over a connection106in accordance with an illustrative embodiment. The connection106, in some embodiments, is a network tunnel established over a network108(shown inFIG.2A) between the network device (e.g.,102) and the virtualized standby device (e.g.,104) (shown inFIG.2B). In some embodiments, the virtualized standby device is executed in a cloud infrastructure and communicating over a network. In other embodiments, the connection106is a direct communication link, e.g., direct serial communication link such as ethernet cross-over cable, ethernet, USB, FireWire, SVL link, Sonet/SDH, Frame-relay, X.25, T1/E1, and the like, that can sufficiently provide control plane and data plane updates. Direct communication link can also refer to wireless links such as WiFi (e.g., 802.11), LTE 4G/5G, WiMAX, and the like.

As discussed above, a stackable switch can be a network switch that is fully functional when operating as a standalone device, but which can also be set up to cooperatively operate together with one or more other network switches as a group. Stackable switches, and similar class device, can provide redundant operations to individual switches in switchover operations. Non-stackable switches also refer to switches configured to operate as a standalone device. Stackable and non-stackable switches may be configured with modules to perform virtualized or mobile virtualized hardware switchover operations as described herein.

InFIG.1A, the active network device102ais shown comprising a plurality of ports124coupled to forwarding engine, which is coupled to a forwarding processor126via a bus structure128(shown as “switch fabric”128). Forwarding processor(s)126can be used to execute routing protocols, e.g., by maintaining routing information and forwarding table(s). The forwarding processor126may have access to fast memory130(such as ternary content-addressable memory (TCAM), CAM, SRAM, buffers, etc.) and local memory132(e.g., dynamic random-access memory (DRAM), SRAM)).

The forwarding processor126may communicate with a host processor134(also referred to herein as a host CPU and shown as “Host Processor(s)”134). As discussed above, a host CPU (134) generally refers to a core of a microprocessor or microcontroller, e.g., having RISC or CISC architecture, that is configured to execute general computer instructions (i.e., applications, middleware) within the framework of an operating system. Here, computer instructions generally refer to general instructions, preferably, that are prepared not to be specifically tied to a particular computer architecture. The host CPU134interfaces with the bus interconnect114(e.g., PCI or PCIe (PCI-express) bus) that serves as a data plane interface to the forwarding processors126and/or other components of the data-plane112. PCIe can refer to PCI-X, PCI-express 16x, PCI-express 1x, and the like. In some embodiments, the host CPU134and forwarding processor126are co-located on a same printed-circuit or circuit assembly136. In yet other embodiments, the host processor134is used as a substitute for, or integrated with, the forwarding processor126or components thereof, e.g., in a network-on-a-chip (NoC). The bus interconnect114provides connectivity between the host CPU134and the data plane112, which access the bus interconnect114through bus drivers137.

InFIG.1A, the forwarding processor126is shown to connect through the switch fabric128to a plurality of forwarding engines comprising one or more ASIC(s)140, memory and memory-like resources142(e.g., CAM, registers, buffers), and driver144. The forwarding engine is configured to route a frame received at one of its port to another port or to route the frame to the switch fabric128to other ports in the network switch. Other configurations and implementations may be implemented. An “ASIC” as used herein may refer to a customized application specific integrated circuit as well as configurable integrated circuit such as field-programmable gate array (FPGA) and complex programmable logic device (CPLD).

Broadly stated, when a frame (also referred to as a packet) is received at a port124at the forwarding engine, the frame is driven over an internal bus of the engine based on forwarding decision rendered by the ASIC140(or local processor) or is driven over the switch fabric128to other ports based on forwarding decision rendered by the forwarding engine. Such frames are processed by the data plane (also referred to as the forwarding plane, among other) of the network device (e.g.,102). InFIG.1A, the data-plane112is shown as any component and associated resources involved in the forwarding and routing of user traffic. The data-plane (e.g., forwarding engine) renders the forwarding decision by accessing a forwarding or routing table to look-up a destination MAC address of the frame. Frames associate with the control plane (e.g., those associated layer-2 and/or layer-3 control protocol such as Spanning Tree Protocol (STP), Open Shortest Path First (OSPF), Multiprotocol Label Switching (MPLS), Internet Group Management Protocol (IGMP), Intermediate System to Intermediate System (IS-IS), Border Gateway Protocol (BGP), PIM, Enhanced Interior Gateway Routing Protocol (EIGRP), Routing Information Protocol (RIP), Virtual LAN (VLAN), Virtual Extensible LAN (VxLAN), etc.) and management plane (e.g., associated with telnet, command line interface (CLI), file transfer protocol (FTP), trivial file transfer protocol (TFTP), syslog, secure shell (SSH), simple network management protocol (SNMP), Hypertext Transfer Protocol (HTTP), HTTP Secure (HTTPS), access control lists (ACL), etc.) may also be received at the ports but are generally routed to the host processor134to update control and management operation of the active switch (e.g.,102).

As noted, control plane updates are forwarded to and processed by the host CPU134. These can include, but are not limited to, updates associated with newly learnt MAC entries, updates associated with Layer 3 entries (e.g., IPv4 or IPv6), updates associated with EtherChannel membership, updates associated with Spanning Tree Protocol topology-change, updates associated with protocol state or resource state change; and/or updates associated with hardware resource transition change. In such embodiments, when a control plane associated packet is received, it is directed through the forwarding engine and data plane components112to the bus interconnect114to the host CPU134. The host CPU134then determines any updates to the data-plane-associated tables of the data plane112and write that updates to the bus interconnect114, which are updated by the data plane112.

The network device (e.g.,102), as a redundant or non-redundant system, may include additional cards comprising processors and memory to perform other control or supervisory operations of the network device. In some embodiments, the additional cards may be implemented in general-purpose or special purpose computing devices environments, virtual network environment, or configurations. Components on the additional cards may be connected to other components via the bus interconnect114or the switched fabric128. The bus interconnect114also may allow the host CPU134to connect to the data-plane112via a host CPU driver138.

Computer-executable instructions, such as program modules, being executed by a computing device (e.g., via the host CPU) may be used. Generally, program modules include routines, programs, objects, components, data structures, etc. that perform particular tasks or implement particular abstract data types. Computer-executable instructions may execute the Protocol and/or Resource State Transition Tracker functionality to be discussed below.

Computing device typically includes a variety of computer readable media. Computer readable media can be any available media that can be accessed by the device and includes both volatile and non-volatile media, removable and non-removable media. Computer readable media may be used to store executable instructions for the virtualized or mobile virtualized hardware switchover operations. Computer storage media include volatile and non-volatile, and removable and non-removable media implemented in any method or technology for storage of information such as computer readable instructions, data structures, program modules or other data. Memory, removable storage, and non-removable storage are all examples of computer storage media. Computer storage media include, but are not limited to, RAM, ROM, electrically erasable program read-only memory (EEPROM), flash memory or other memory technology, CD-ROM, digital versatile disks (DVD) or other optical storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other medium which can be used to store the desired information, and which can be accessed by computing device. Any such computer storage media may be part of computing device. Computer-executable instructions and computer storage media are well known in the art and are not discussed at length here.

Computing device may contain communication connection(s) that allow the device to communicate with other devices. Computing device may also have input device(s) such as a keyboard, mouse, pen, voice input device, touch input device, etc. Output device(s) such as a display, speakers, printer, etc. may also be included. All these devices are well known in the art and are not discussed at length here.

Because of the limited redundancy of supporting data-plane components, implementations of the protocol state transition and/or resource state transition tracking module in such systems can be particularly beneficial to overall system uptime.

In the mobile virtualized standby switch (e.g.,104,104d), and as shown inFIG.2B, stub and/or simulated applications250(shown as250aand250b) of non-control-plane associated application and processes are executed to reduce computation loads of such non-control-plane associated application and processes so the computational resources can be used for the execution of control-plane associated applications and processes. In some embodiments, the stub and/or simulated applications250is configured to return a simple and valid, though not necessarily correct, result or response for a given function call. Example of non-control-plane associated application and processes include certain security, monitoring, management, and house-keeping operations.

Operating system processes and various applications running on enterprise switches and access switching devices are often custom built to run on specialized platforms. To this end, various operating system processes and applications running on enterprise switches and access switching devices may not be executed on any microprocessors and hardware. For such customized operation, “stub” functionality for some of the components can be executed on mobile computing hardware that are missing such custom hardware. In addition, the instant operating system and application package of the mobile computing device can include equivalent functionality through simulation functions.

In some embodiments, simulation modules are used where possible and stub modules are used where simulation cannot be performed. Although use of stub and simulated operation may lead to system instability over time, the exemplary system and method are configured to employ them for a temporary and limited duration. In such limited use, which can be in the order of a few minutes, the exemplary system and method can provide sufficient operating system and application responses to perform a fast upgrade operation or reboot for the physical switch.

Most manufacturers of enterprise switches and access switching devices have development package to test various modules of enterprise switches and access switching devices using stub applications and simulators. Such development package, in some embodiments, is configured to execute a hardware, for example, with HA/ISSU/SSO capability.

Example Virtualized or Mobile Virtualized Network Device

As discussed above,FIGS.1A,1B,1C,2A,2B, and4, each shows the network device (e.g.,102) configured with a control plane110and a data plane112that are connected over a bus interconnect114(e.g., PCI or PCIe (PCI-express) bus). PCIe can refer to AXI, SPI (system packet interface), PCI-X, PCI-express 16x, PCI-express 1x, PCIe 4.0, PCIe 5.0, PCIe 6.0, and the like.

The virtualized or mobile virtualized standby switch (e.g.,104) as a remote or cloud server (or as portable or mobile devices) has a corresponding set of control plane116(shown as a “Remote/Cloud Processors”116) and bus interconnect118(seeFIGS.2A and2B), or a logical equivalent thereof, but no corresponding data plane. That is, the hardware and software of the virtualized or mobile virtualized standby switch104can execute the same or compatible operating system and applications as that of the network device (e.g.,102) and thus mimic the control plane operations of the network device. But, the virtualized or mobile virtualized standby switch (e.g.,104) does not necessarily have the corresponding hardware to execute a corresponding data plane.

In each ofFIGS.1A,1B,1C,2A,2B, and4, the network device (e.g.102) and the virtualized or mobile virtualized network device (e.g.,104) each includes a control-plane-data-plane interface transport module120(shown as “VPCI”120,122, respectively inFIGS.2A and2B, and also referred to herein as a “virtual PCI” module or “virtual AXI”120,122) that serves as a virtual data-plane driver interface, or a logical equivalent thereof. The control-plane-data-plane interface transport module (e.g.,120,122) is configured to transport bus transactions between the active network device (e.g.,102) and the virtualized or mobile virtualized network device (e.g.,104).

Control-plane updates. The control-plane data-plane interface transport module (e.g.,120) of an active network device (e.g.,102) is configured, in some embodiments, to implement read and write transaction. That is, it can read bus transactions from the data plane112of an active network device (e.g.,102) (intended for its control-plane110) and provide the read transaction to the network interface, which transmits that transaction as a message over the network108to the virtualized network device (e.g.,104) inFIG.2A. In other embodiments, and as shown inFIG.2B, the message is transmitted over a direct connection communication link106. The virtualized network device (e.g.,104) receives the messages and write, via a corresponding control-plane-data-plane interface transport module122, bus transactions to a physical bus interconnect (e.g.,FIGS.2A and2B), or a logical equivalent of (not shown), of the virtualized or mobile virtualized network device to write that control plane110.

InFIG.1A, the control-plane-data-plane interface transport module120is implemented as an integrated component of the active network device102a. InFIG.1B, the control-plane-data-plane interface transport module120is implemented as a core or logic circuit146in an ASIC140. InFIG.1C, the control-plane-data-plane interface transport module120is implemented in a core or logic circuit of an auxiliary card150.

For simplicity and in relation toFIGS.2A and2B, the control-plane data-plane interface transport module (shown as “VPCI”120) is shown to read (204), from the bus interconnect114, bus transactions written (202) by the data plane112of an active network device102and directs (206) that read bus transaction as a message to a network interface207to transmit (208) the message over the network108to a corresponding control-plane data-plane interface transport module122, or a logical equivalent thereof, executing at the virtualized or mobile virtualized network device104.

In some embodiments, the control-plane data-plane interface transport module122of the virtualized or mobile virtualized network device104then receives (208) the message (e.g., encapsulated packet) from the network interface215, unpackages the message, and writes (210) a corresponding bus transaction to the bus interconnect118to be read (212) by the control plane116of the virtualized or mobile virtualized network device104. To this end, control plane updates received by the data plane112of the active network device (e.g.,102) are transported to the control-plane116executing on the virtualized or mobile virtualized network device104without any modification to the data-plane112nor without the data-plane knowing that the control-plane110of the active network device102is unavailable.

In other embodiments, the control-plane data-plane interface transport module122is implemented as a logical equivalent (not shown) of the physical module, for example, as a software module executing in the remote processor116in the virtualized or mobile virtualized network device (e.g.,104).

The message, in some embodiments, includes a tunnel header, packet header, and packet payload (e.g., as shown inFIG.7). In some embodiments, the message is a transmitted using existing stack-over operations which may encapsulate the packet header and packet payload with an SVL header to which the resulting packet is encapsulated a tunnel header associated with the connection106.

The messages can nevertheless be in any format or protocol. In some embodiments, the bus transaction is encapsulated as a payload in an encapsulated packet, which serves as the message. In some embodiments, multiple bus transactions may be encapsulated as the payload in single encapsulated packet.

In addition, although the network interface207is shown inFIGS.2A and2Bto be natively integrated into the active network device102, it should be appreciated that the network device207could be implemented as a modular component that is plug-able into the active network device102.

Data-plane updates. Similarly, the control-plane data-plane interface transport module122of the virtualized or mobile virtualized network device104is configured to read bus transactions, or equivalents thereof, from the control plane116of the virtualized or mobile virtualized network device (e.g.,104). The read bus transaction, or its equivalent, is provided to the network interface215and is transmitted as a message over the network108to the active network device (e.g.,102), which reads the message. The control-plane data-plane interface transport module120of the active network device (e.g.,102) uses the message to write bus transactions to the bus interconnect of the active network device (e.g.,102) to write to the data plane112.

InFIG.2A, the control-plane data-plane interface transport module122of the virtualized or mobile virtualized network device (e.g.,104) is configured to read (210), from the bus interconnect118, bus transactions written (212) by the control plane116of the virtualized or mobile virtualized network device (e.g.,104) and directs (214) that read bus transaction as a message to a network interface215to transmit (208) over the network108to the control-plane data-plane interface transport module120of the active network device (e.g.,102). In other embodiments, and as shown inFIG.2B, the message is transmitted over a direct connection communication link106. The control-plane data-plane interface transport module120then writes (204) a corresponding bus transaction to the bus interconnect114to be read (212) by the data plane112of the active network device (e.g.,102). Data plane updates determined by the control plane (e.g.,116) of the virtualized or mobile virtualized standby device (e.g.,104) are transported to the data-plane (e.g.,112) of the active network device (e.g.,102) without any modification to the control-plane (e.g.,116) nor without the control plane (e.g.,116) knowing that it is a proxy/back-up control plane110of the active network device (e.g.,102).

Again, the messages can be in any format or protocol. In some embodiments, the bus transaction is encapsulated as a payload in an encapsulated packet, which serves as the message. In some embodiments, multiple bus transactions may be encapsulated as the payload in single encapsulated packet.

FIGS.1A,1B,1Ceach shows example implementations of the control-plane-data-plane interface transport module120as implemented in the network device (e.g.,102).

Example Control-Plane Data-plane Interface Transport Module #1.FIG.1Ashows an example implementation of a control-plane-data-plane interface transport module120implemented as an integrated component of the active network device102ain accordance with an illustrative embodiment.

InFIG.1A, the active switch102aincludes the control-plane-data-plane interface transport module120, which comprises an upgrade core or upgrade processor146(shown as “Upgrade Core (e.g., M3)”146) and bus interconnect driver148. The processor146can be implemented in a microprocessor, FPGA, ASIC/DSP, or other like instruction processing device. The upgrade core or processor146comprises core of a microprocessor or microcontroller, e.g., having RISC or CISC architecture, that is configured to execute general computer instructions (i.e., applications, middleware) as well as low-level computer instructions (e.g., microcode, Assembly instructions) within the framework of an operating system. The upgrade core or processor146may be a lightweight processor suitably sized to perform encapsulation and decapsulation operations or packet. In some embodiments, the upgrade core or processor146may be executed in a core of a forwarding processor126, which may interface with the bus interconnect114through the driver137. Other than Cortex M3, ARM A7/A15/A53 may also be used here. When used as a helper to Host-CPU, these are generally termed as “services processor.”

Example System #2—ASIC Core VPCI/VAXI.FIG.1Bshows an example implementation of a control-plane-data-plane interface transport module120as a virtual data-plane driver interface implemented as a core or logic circuit146(shown as “Upgrade Core”146) in the ASIC140in accordance with an illustrative embodiment. In some embodiments, the ASIC140includes an IP core comprising a CPU or DSP unit, peripheral interfaces, standard interfaces, integrated memories, and/or reconfigurable, uncommitted logic. The ASIC140may include a driver to directly write and read to the bus interconnect114or indirectly through the switch fabric.

Example System #3—Auxiliary Card VPCI/VAXI.FIG.1Cshows an example implementation of a control-plane-data-plane interface transport module120as a virtualized or mobile virtualized data-plane driver interface implemented as a core or logic circuit in an auxiliary card150in accordance with an illustrative embodiment. The auxiliary card150may include a printed-circuit or circuit assembly configured to interface with the bus interconnect114(as shown) or the switch fabric (not shown). The auxiliary card150, e.g., a logical data plane interface card, may include a core or logic circuit146, a driver115, and the network interface207.

In some embodiments, a library of images comprising the operating system and applications for a given enterprise switch may be generated and installed on specific mobile computing devices to be use in virtualized or mobile virtualized stateful switchover operation with the given enterprise switch as it undergoes fast upgrade operations.

Example Orchestration of Virtualized Standby Switch Using Stateful Switch-Over

FIG.3Ashows a method of establishing a virtualized standby switch (e.g.,104) using virtualized hardware switchover operation in accordance with an illustrative embodiment. In some embodiments, the virtualized hardware switchover operation (or virtualized stateful switchover operation) is based on a stateful switchover operation (SSO or SWO) configured to provide fault resistance capabilities for an active/primary stackable switch/chassis by employing a redundant supervisor engine (shown as306), on a same or different chassis, having similar or same capabilities to the primary supervisory engine and hardware (shown as304), to take over network operation of the primary supervisor engine (304) when the primary supervisory engine (304) fails or becomes unavailable. Stateful switchover operation relies on redundant hardware (e.g.,306) in a standby network device to take over operation of the active network device (e.g.,304) to continue to forward network traffic with no loss of sessions when the active network device becomes unavailable.

A standby network device forms a stack with the active device. Once a stacking configuration is formed between an active device and a standby device, SSO (Stateful synchronization Operation) automatically is initiated and continues until the configuration of active device is synchronized with Standby device. A trigger for SWO (SWitchover operation) is then provided and the Standby device takes over as the Active device, and prior active device goes through a reboot.

InFIG.3A, the virtualized stateful switchover operation includes stateful switchover mechanisms to fully initialize the standby network device (shown as104), e.g., via a Virtual Switch Link (VSL), after the device104has been orchestrated in a remote server or cloud server302, and then synchronize critical state information between the active and standby processors. Virtualized stateful switchover operation performs the orchestration to instantiate the remote server or cloud server302and to establish a secure tunnel106between the remote/cloud server302and the active network device102. In addition, the virtualized stateful switchover operation instantiates the control-plane-data-plane interface transport module (e.g.,120and122, respectively) in each of the network devices (e.g.,102,104) to provide transport operations of control plane updates from the active network device (e.g.,102) to the virtualized standby network device (e.g.,104) and to provide transport operations of the resulting data plane updates back to the active network device (e.g., active stackable or non-stackable switch) from the control plane116of the virtualized standby network device (e.g.,104).

Example Orchestration of Virtualized Redundant Switch Using High-Availability Operation

FIG.3Bshows another method of establishing a virtualized redundant switch, as another form of virtualized standby switch, using a virtualized high availability operation in accordance with an illustrative embodiment. To this end, the term “virtualized redundant switch” and “virtualized standby switch” are used interchangeably in the instant disclosure.

The virtualized high availability operation is derived from high availability (HA), or like, operation. In virtualized high availability operation, like high availability operation, the network devices are joined by a configurable control link and data synchronization link. The control link is used to communicate the status of the network devices. The data synchronization link is used to transfer stateful information to synchronize the stateful database for the calls and media flows. Each pair of redundant interfaces may be configured with the same unique ID number.

InFIG.3B, the virtualized high availability operation includes high availability mechanisms to fully initialize a second and redundant network device after the virtualized network device has been orchestrated in a remote server or cloud server, and then synchronize state information between the active and redundant processors. Virtualized high availability operation performs the orchestration to instantiate the remote server or cloud server and to establish a secure tunnel between the remote/cloud server and the active network device. In addition, the virtualized stateful switchover operation instantiates the control-plane-data-plane interface transport module in each of the network devices to provide transport operations of control plane updates from the active network device to the virtualized standby/redundant network device (e.g., virtualized standby/redundant switch) and to transport the resulting data plane updates back to the active network device (e.g., active stackable or non-stackable switch) from the control plane of the virtualized standby/redundant network device.

Example Orchestration of Virtualized Mobile Standby Switch Using Stateful Switch-Over

FIG.3Cshows a method of establishing a mobile virtualized standby switch (e.g.,104) using a mobile virtualized hardware switchover operation in accordance with an illustrative embodiment. In some embodiments, the mobile virtualized hardware switchover operation is based on a stateful switchover operation (SSO) configured to provide fault resistance capabilities for an active/primary stackable switch/chassis by employing a redundant supervisor engine (shown as306,308), on a same or different chassis, having similar or same capabilities to the primary supervisory engine and hardware (shown as304,310), to take over network operation of the primary supervisor engine (304) when the primary supervisory engine (304) fails or becomes unavailable. Stateful switchover operation relies on redundant hardware (e.g.,306,308) in a standby network device to take over operation of the active network device (e.g.,304) to continue to forward network traffic with no loss of sessions when the active network device becomes unavailable.

Mobile virtualized stateful switchover operation, similar to stateful switchover operation, in an upgrade operation, establishes the upgrading network device (e.g.,102) as an active network device and the mobile virtualized network device (e.g.,104) as a standby network device. The mobile virtualized stateful switchover operation, similar to stateful switchover operation, or using associated stateful switchover programs, may perform synchronization of the control plane state information to synchronize startup and running configurations. Once synchronized, the mobile virtualized stateful switchover operation may switch control plane operation from the active network device to the virtualized or mobile virtualized network device so that reconciliation may not need to be performed since the states have already been kept in sync by the applications.

InFIG.3C, the mobile virtualized stateful switchover operation includes stateful switchover mechanisms to fully initialize the mobile network device104, e.g., via a Virtual Switch Link (VSL), after the mobile device104has initiated execution of the control plane processes of the physical switch, and then synchronize critical state information between the active and standby processors. Mobile virtualized stateful switchover operation establishes a direct communication link (shown as106a) between the mobile network device104and the active network device102(e.g.,102a,102b,102c). In addition, the mobile virtualized stateful switchover operation instantiates the control-plane-data-plane interface transport module (e.g.,120,122as described in relation toFIG.2B) in each of the network devices (e.g.,102,104) to provide transport operations of control plane updates from the active stackable network device (e.g.,102) to the mobile virtualized standby network device (e.g.,104) and to provide transport operations of the resulting data plane updates back to the active network device (e.g., active stackable switch) from the control plane (e.g.,116) of the mobile virtualized standby network device104d.

Example Fast Upgrade System Using a Virtualized Standby Switch

FIG.4shows an exemplary timing diagram400of a virtualized or mobile virtualized hardware switchover operation between an active network device (shown as102d) and a virtualized remote/cloud or mobile standby switch (shown as104d) in accordance with an illustrative embodiment. InFIG.4, prior to performing a virtualized or mobile virtualized hardware switchover operation (shown as406), say, for a fast upgrade operation, for a standard data packet, the active switch102dis shown (402,402a) to receive (408a) the data packets at a port124(shown as “Port(s)”124), which are routed (408b) by the forwarding engine140(shown comprising “RP/ASIC/Switch Fabric”) to another port (still shown as124) using (408c) data-plane-associated resources112(shown as “Routing/Forwarding Tables”112). Also, inFIG.4, for a control plane packet with a simple control plane update, the active switch102dis shown (404) to receive the control plane packet at a port124, which are routed (410a) through the forwarding engine140and routed (410b) through a bus interconnect114(shown as a “data-plane interface”114) to the control plane110(shown as “host CPU”110). In this example, the control plane110cthen updates (410c) a data-plane resource112by writing (410d) to the data plane interface114.

In the example of an upgrade operation, and as shown inFIG.4, the virtualized or mobile virtualized hardware switchover operation is initiated at step412with an upgrade command received (412) by an upgrade controller146. In some embodiments, the upgrade controller146is an application executing a processing core or logic circuit at the active network device102d. In other embodiments, the upgrade controller146is an application executing on the processing core or logic circuit at an external controller. For a remote/cloud device, the upgrade controller146directs (414) the instantiation of a virtualized standby switch104din a remote or cloud infrastructure (e.g., remote or cloud server) to provide a redundant control plane116(shown as “Remote CPU”116and also referred to herein as control plane116) to the control plane executing on the host CPU110. For a mobile computing device, the upgrade controller146directs (414) the initiation of the mobile virtualized standby switch instance104executing on a mobile computing device to provide a redundant control plane116(shown as “Remote CPU”116cand also referred to herein as control plane116c) to the control plane executing on the host CPU110c.

The active network device102d(as a physical switch) and the virtualized or mobile virtualized standby switch104dpreferably forms a stack, e.g., using HA operations, such as ISSU, SSO, or like synchronization and management operations. For simplicity, in this example, switchover, HA, ISSU, SSO synchronization operations will be referred to as switchover synchronization.

In some embodiments, for cloud/remote device, instances of virtualized or mobile virtualized standby switches are pre-instantiated in the remote or cloud infrastructure to which the upgrade controller146can then direct the assignment of a pre-instantiated virtualized or mobile virtualized standby switch to the active network device102d. Once instantiated, the active network device102dand the virtualized or mobile virtualized standby switch104dare joined in stacked mode with the active network device102dset (416a) in active mode and the virtualized or mobile virtualized standby switch104dset (416b) in standby mode. The active network device102dthen performs bulk synchronization operation of its control-plane state, as well as subsequent incremental synchronization (418), to the virtualized or mobile virtualized standby switch104d.

For mobile computing device, the device is pre-configured with an image of the operating system and control-plane application but in hibernation or sleep mode. The upgrade controller146can then direct the assignment of a mobile virtualized or mobile virtualized standby switch to the active stackable network device102, which brings it to the non-sleep or non-hibernating mode.

During the initialization process (420), the control-plane-data-plane interface transport modules120,122are initialized (shown as422aand422b) in the respective active network device102dand virtualized or mobile virtualized standby switch104b. In some embodiments, the upgrade controller146pushes the instructions for the control-plane-data-plane interface transport modules120,122, or its equivalent, to the active network device102dand virtualized or mobile virtualized standby switch104b, e.g., as a part of the initialization process. In other embodiments, the system image for the active network device102dand virtualized or mobile virtualized standby switch104dincludes the instructions for the control-plane-data-plane interface transport modules to which the upgrade controller146can then initialize.

The initialization process (420) ends once both the control planes110,116of the active network device102dand virtualized or mobile virtualized standby switch104bare synchronized to have the same control-plane states, and the control-plane-data-plane interface transport modules120,122are instantiated and executing. With the control-plane-data-plane interface transport modules120,122executing to transport bus interconnect transactions between the physical and virtualized or mobile virtualized switches (102d,104d), the control plane110of the active network device102d(and not the data plane) can switch from an active mode to a standby mode, and the control plane116of the virtualized or mobile virtualized standby switch104dcan switch from the standby mode to the active mode. With the control plane110of the active network device102dbeing in the standby mode, it can then be disabled (shown as424), e.g., for a fast upgrade operation where it reboots to a new system image, or is rebooted. During this time, the data-plane of the active network device102dcontinues its forwarding operations of packets and any control plane associated updated (e.g., to the data plane tables and resources or the control plane) are made by the secondary control plane116of the virtualized or mobile virtualized standby switch104dby way of the control-plane-data-plane interface transport modules120,122.

InFIG.4, during the virtualized or mobile virtualized hardware switchover operation (shown as424), the data-plane of the active switch102dcontinues to service received from the packets from the network. As shown, upon a data packet arriving (426a) at a port124, the forwarding engine140routes (426b) the packet to another port124using (426c) data-plane-associated resources112, And for control plane updates (430), the active switch102dis shown to receive (428a) the control plane packet at a port124, which are routed through the forwarding engine140and routed (428b) to the driver of a bus interconnect114. These data and control-plane packets may be received from peer network devices (e.g.,504shown inFIG.5) as well as enterprise-level network controllers (e.g., Cisco Digital Network Architecture (DNA) controller, OpenStack controller, or the like, shown as506inFIG.5). However, rather than the control plane110(which is unavailable) reading the bus interconnect114, the control-plane-data-plane interface transport module120dof the active switch102dreads (428c) the bus interconnect114and transports (428d) the read transaction, as a message, through the network to the control-plane-data-plane interface transport module122of the virtualized or mobile virtualized standby switch104d. The control-plane-data-plane interface transport module122then writes (428e) a transaction to the bus interconnect118of the virtualized or mobile virtualized standby switch104d, which is then read (428f) by the control plane116of the virtualized or mobile virtualized standby switch104dto process (428g) the control plane update.

In instances where the control plane has a data plane update, the control plane116writes (430a) to the bus interconnect118. The control-plane-data-plane interface transport module122reads (430b) the transaction and transports (430c) the transaction, as a message, through the network (for a virtualized standby switch), or established communication link (for the mobile virtualized standby switch), to the control-plane-data-plane interface transport module120of the active switch102d. The control-plane-data-plane interface transport module120then writes (430d) the transaction to the bus interconnect114(as if written by the native control plane), which is written (430e) to the addressed data-plane resources.

It should be clear that even though the control plane of the active network device102dis in standby mode, the data plane continues to maintain the same active mode. And, while the control plane of the virtualized or mobile virtualized standby switch is in active mode, the virtualized or mobile virtualized standby switch itself does not have a local data plane—the control plane of the virtualized or mobile virtualized standby switch serves to temporarily maintain hitless or near-hitless control-plane operations during the entire upgrade or reboot processes of the control plane of the active network device102d.

Fast Upgrade System with Virtualized or Mobile Virtualized Stateful Switchover Operation

FIG.5shows a system500configured to perform a fast upgrade operation using the virtualized or mobile virtualized hardware switchover operation in accordance with an illustrative embodiment.

As discussed above in relation toFIGS.1-4, the fast upgrade operation generally include instantiating a virtualized switch (e.g., a virtualized standby switch) on a cloud or a local/remote server that has connectivity to a physical switch (e.g., an active stackable or non-stackable switch). And as discussed, in some embodiment, the local/remote server is implemented in a mobile computing device, e.g., a laptop, tablet, small compact-factor single board computers, mini-PC, stick PC, and the like. The physical switch and the virtual switch then can form a stack, e.g., using processes of software upgrade using HA, such as ISSU and SSO mechanisms and similar to a set of two physical switches in a stack configuration mode. The physical switch and the virtual switch may form a stack using front-side stacking (SVL), e.g., using front-panel port access.

In some embodiments, in addition to using HA, such as ISSU and SSO mechanisms, the virtualized switch is further configured to execute both the control-plane software of the physical switch and the data-plane drivers, including, for example, forwarding engine driver (FED), forwarding engine SDK (software development kit), and ASIC drivers. InFIG.5, the control plane software/instructions may be stored and retrieved from a stackable switch image library (shown as502) or upgradable switch image library (e.g., for non-stackable switches). In some embodiments, the library502is stored in a remote or cloud server. An example of a remote or cloud image library system is Cisco Software Image Management (SWIM) system. In other embodiment, the library is a computer readable medium (e.g., DVD, CD, compact flash, and other persistent memory device).

The device access layer (e.g., data-plane access layer) in the data-plane driver of the virtualized switch may implement a logical data-plane interface (e.g., virtual PCI (vPCI), Virtual AXI (vAXI), and other control-plane-data-plane interface transport modules) to provide communication between the data-plane drivers running on the virtualized switch and the data-plane of the physical switching. The data-plane drivers in the virtualized switch may be masked to the underlying data-plane device (or the logical data-plane interface endpoint) and the control plane of the virtualized switch can view and access the entire memory map of the data-plane device. A logical data-plane interface of the active switch may implement a tunnel (or a socket) implemented using technologies such as GRE, VxLAN, or similar mechanisms. Raw register/memory access operations are then sent and received over the logical data-plane interface.

In general, the data-plane device in the physical switch are configured to send punt packets, switch ASIC packet-descriptors, and other management packets to the virtualized switch. This can be realized through GRE, VxLAN, or similar mechanisms, as discussed above. The punt packet along with the Switch ASIC Packet-descriptors may be encapsulated with stack header and then an appropriate tunnel header.

Functionally, the virtualized switch is equivalent to another physical switch during the software upgrade.

FIGS.6and7A-7Dshow an example fast upgrade operation using the virtualized hardware switchover operation in accordance with an illustrative embodiment.FIG.6shows a timeline for a fast upgrade operations using an exemplary virtualized hardware switchover operation whileFIGS.7A-7Dshow sub-operations that may be performed.

InFIG.6, the process600is shown to include a virtualized switch “S2” (shown as104) being first instantiated (shown as “Create S2”602) in a cloud, local, or remote machine to be used to upgrade a physical switch “S1” (shown as102). In some embodiments, other computing device may be used to host the virtualized standby switch, including portable computing devices as discussed herein.

The physical switch “S1”102is shown running (604) in standalone mode and is operating in active mode within a switchover operation. InFIG.6, the physical switch is shown to be executing switch image version “16.12.1”. The instantiation may include the creation of a container or virtual machine in such infrastructure along with an operating system, drivers, and control-plane application(s) as described in relation toFIGS.4and5. In some embodiments, the instantiation is directed by a upgrade controller, which may be executing on the physical switch “S1” or a remote computing device.

After the virtualized or mobile virtualized switch “S2”104is instantiated, an SSO operation is triggered (shown as “SSO”606). In operation606, the virtualized or mobile virtualized switch “S2”104is joined (608), e.g., via SVL connectivity (where SVL is StackWise Virtual), in standby mode to the active switch “S1” (shown as “S2joins S1in stack mode”608) and bulk synchronization (the start is shown as606and the end is shown as614) is performed. The SVL is an inter-chassis system link between two stack members in an SVL domain. An SVL connection may not run any network protocol and may remain transparent in Layer 2 and Layer 3. The virtualized or mobile virtualized standby switch “S2”104is also executing the same or compatible system image as the physical switch “S1”102, shown as switch image version “16.12.1”.

The software upgrade process is then started (612) and the physical switch “S1”102, as the active node, continues to perform bulk synchronization operation (608,614) until step614. The bulk synchronization (606) synchronizes the control-plane state to the virtualized or mobile virtualized switch “S2”104so the control-plane states of the switches “S1” and “S2”102,104are the same. During the synchronization, the physical switch also prepares for reboot and/or upgrade.

FIG.7Ais a diagram illustrating an example synchronization operation608,614between the active and standby switches for one class of switches. It should be understood that similar, though different synchronization operations, may be performed for other classes of switches.

In this example, the class of devices in the example has a control plane that is separate to the forwarding plane, and any update is passed from the control plane to the data plane through the data flow shown inFIG.7A. Specifically, inFIG.7A, each of the physical and virtualized or mobile virtualized switches “S1” and “S2” is executing a control plane daemon process (“IOSd”) (shown as702aand702b, respectively) and a control-plane forwarding manager process704(“Control Plane Process”) (shown as704aand704b, respectively). The control plane daemon process (“IOSd”)702a,702bsend updates to the control-plane forwarding manager process704a,704b, respectively, which sends updates to the forwarding engine driver (“FED”) (shown as706aand706b, respectively), which provides the driver interface to the ASIC and forwarding plane hardware of the switch (shown as112). Because the virtualized or mobile virtualized switch104is a computing device in the cloud, local, or remote machine (or a portable machine), it does not include a data-plane and the forwarding engine driver (“FED”)708is shown to write to a virtual data-plane. In some embodiments, the virtual data-plane is a memory table or other addressable construct that is similar in construct to the data-plane (e.g.,112e).

For the synchronization process614, the control plane daemon process (“IOSd”)702aof the physical switch “S1”102is synchronized (710) to the control plane daemon process (“IOSd”)702bof the virtualized or mobile virtualized switch “S2”104. And, the control-plane forwarding manager process704aof the physical switch “S1”102is synchronized (712) to the control-plane forwarding manager process704bof the virtualized or mobile virtualized switch “S2”104. As noted, in the case of the virtualized or mobile virtualized switch “S2”104, the data-plane may be a NULL (sink). Indeed, bulk synchronization operations and incremental synchronization operations (614) may be performed in this manner.

Referring back toFIG.6, subsequent incremental synchronization operation (614) may also be performed to maintain control state synchronization between the physical and virtualized or mobile virtualized switches “S1” and “S2”102,104. In some embodiments, the control-plane state is synchronized by the control plane daemon process (“IOSd”) and control-plane forwarding manager process between physical switches and virtualized or mobile virtualized switches “S1”102and “S2”104, for example, as described in relation toFIG.7A.

Once the control-plane states are synchronized to the same states, the virtualized or mobile virtualized switch “S2”104is directed to assume the active role while the physical switch “S1”102assumes the standby role. Once in the active role, the virtualized or mobile virtualized switch “S2”104prepares (618) the state of the data-plane device and programs it, e.g., in some embodiments, using the logical data-plane interface (e.g., vPCI), which may be initiated at this sequence. In other embodiments, the data-plane device112may be programmed by the control plane110of the physical switch “S1”102prior to it becoming unavailable and under direction from the control plane of the virtualized or mobile virtualized switch. The programming ensures the association of resources and their addresses are consistent between the control-plane and data-plane on the physical and virtualized or mobile virtualized switches “S1”102and “S2”104. Without the programming operation, the data-plane state may have different table indexes or addresses in the data-plane even though the control-plane state of the physical and virtualized or mobile virtualized switches “S1” and “S2”102,104may be identical because the order of operations at the control-plane may not be preserved or performed in the same sequence. To optimize the programming of the data-plane device112of physical switch “S1”102, in some embodiments, the data plane device may be programmed for only resources where such change is expected or had been made. As noted, programming may be implemented using via either logical data-plane interface, or through the control-plane110of the physical switch “S1”102.

In yet another embodiment, the programming may involve generating an index translation table that translates addresses between i) old indexes associated with the data plane resource of the physical switches “S1”102and ii) new indexes associated with the data plane resource of the virtualized or mobile virtualized switches “S2”104. The translation can improve the network/switch availability as the programming may be performed very quickly without having to write over data-plane resources of the physical switch “S1”102. Indeed, once a mapping between old and new indexes are generated, ‘read’ and ‘write’ operations can go through the translation table, and the correct indexes/addresses can be accessed.

Following the synchronization of the data-plane states between the physical and virtualized or mobile virtualized switch “S1” and “S2”102,104, the physical switch “S1”102configures its data plane112to switchover to operate in slave mode (620) to the control plane116of the virtualized or mobile virtualized switch “S2”104. Subsequently, the host-CPU of the physical switch “S1”102is disabled (622) and undergoes reboot operation (624). In an upgrade operation, the host-CPU reboots (624) to a new system image. In a reboot operation, the host-CPU reboots (624) to the same system image. The data-plane112continues to operate in the slave mode (620), shown for the duration627, in which it is controlled by the control plane116of the virtualized or mobile virtualized switch “S2”104until the control-plane110of the physical switch “S1”102is restored.

FIG.7Bis a diagram illustrating the physical switch “S1”102operating a reboot/upgrade operation while in slave mode to the control plane116of the virtualized or mobile virtualized switch “S2”104. InFIG.7B, the control plane of the physical switch “S1”102, comprising the control plane daemon process702a, the control-plane forwarding manager process704a, the forwarding-plane forwarding manager706a, and the forwarding-plane driver708aare disabled, and the control-plane-data-plane interface transport module (e.g., vPCI)120,122facilitates the transport of data plane updates and control plane updates between the physical switch “S1”102eand the virtualized or mobile virtualized switch “S2”104c.

InFIG.7B, an update by the control plane of the virtualized or mobile virtualized switch “S2”104cis directed through the control plane of the virtualized or mobile virtualized switch “S2”104c, comprising the control plane daemon process702b, the control-plane process704b, and the forwarding-plane driver706b. The control-plane process704bwrites, e.g., to the FED (forwarding engine driver), which translates it to raw bus-address/value pairs. VPCI takes these raw bus-address/value tuples, and transmits to physical device. And the control-plane-data-plane interface transport module “VPCI”122transmits the update as a message over a network link106to a corresponding control-plane-data-plane interface transport module “VPCI”120executing at the physical switch “S1”102. In the example ofFIG.7B, the control-plane-data-plane interface transport module “VPCI”120is executing in an upgrade processor (shown as a “M3” processor) as described in relation toFIGS.1A,1B, and1C. The control-plane-data-plane interface transport module “VPCI”120provides the update to the upgrade processor146which writes it to the addressed data-plane resource (shown as “ASIC”112). In some embodiments, the logical data-plane interface (e.g., VPCI) can work at higher-level transactions can operate on address/value tuples. In other embodiments, the logical data-plane interface (e.g., VPCI) can work on table/index/value tuples.

For control-plane updates from control-plane packets received at the physical switch “S1”102, the control-plane updates are sent from the data plane112as control-plane traffic, e.g., via GRE/VxLAN protocol, to the forwarding-plane driver706b, which relays the control-plane update to the control plane, i.e., host CPU116, of the virtualized or mobile virtualized switch “S2”104. As discussed, other protocols may be used. InFIG.7B, an example structure of a GRE/VxLAN message is shown, which includes a packet payload714, which is encapsulated by a packet header716, an SVL header718, and a tunnel header720.

Referring back toFIG.6, in the example of an upgrade operation, once the control plane of the physical switch “S1”102is brought down, the operating system is booted up (624) with a new system image (shown as image version “16.12.2” from image version “16.12.1”). During the software upgrade, the host CPU is booted with a different and new kernel/system image. Once the kernel is loaded, the operating system is booted. In network devices manufactured by Cisco Technology, Inc, (San Jose, Calif.), operating system may include IOS XE, IOS XR, & IOS Classic. Other operating systems maybe similarly rebooted.

Following bootup of the operating system, the control plane of the physical switch “S1”102is restored (i.e., booted up (626)) and is placed in standby mode. Once in the standby mode, the control plane of the virtualized or mobile virtualized switch “S2”104then performs (628) a control-plane synchronization (e.g., bulk synchronization) to the physical switch “S1”102.

FIG.7Cis a diagram illustrating an example synchronization operation (628) between the active control plane of the virtualized or mobile virtualized switch “S2”104and the standby control plane of the physical switch “S1”102. Similar toFIG.7A, with restoration of the control plane of the physical switch “S1”102in to standby mode, each of the physical and virtualized or mobile virtualized switches “S1” and “S2” is thus executing a control plane daemon process (“IOSd”)702aand702b, respectively, and a control-plane forwarding manager process704aand704b, respectively.

As part of the synchronization operation (628), the control plane daemon process (IOSd)702bof the virtualized or mobile virtualized switch “S2”104is synchronized (722) to the control plane daemon process (IOSd) of the physical switch “S1”102. And, the control-plane forwarding manager process704bof the virtualized or mobile virtualized switch “S2”104is synchronized (724) to the control-plane forwarding manager process704aof the physical switch “S1”102. Bulk synchronization operations and incremental synchronization operations (628) may be performed in this manner.

Once the control-plane states are synchronized to the same states, the physical switch “S1”102switches over (628) and is directed to assume the active role and the virtualized or mobile virtualized switch “S2”104is directed to assume the standby role. Subsequently, the container or virtualized instance of the virtualized or mobile virtualized switch “S2”104may be deleted. InFIG.7D, the control plane is shown to be deleted.

Once in the active role, the physical switch “S1”102prepares the state of the data-plane device and programs it, e.g., in some embodiments, using the logical data-plane interface (e.g., vPCI), which may be initiated at this sequence. In other embodiments, the reprogramming of the data-plane of physical switch is not necessary. In yet other embodiments, a mapping data-base may be created, which maps the indexes of new image (16.12.2) to the indexes of the old image (16.12.1). In some embodiments, cache and flush operation is performed. Example and further description of cache and flush is provided in U.S. application Ser. No. 16/542,183, filed Aug. 15, 2019, which is incorporate by reference herein in its entirety.

Discussion

Software upgrade operation on non-redundant switches can cause the control plane to go down for the entire duration of upgrade. During this time, the switch may be running a stale data-plane, and any protocol State Machine changes are lost. This operation can take several minutes, and is not operationally acceptable for certain applications.

Having the ability to perform software upgrade while keeping the entire control-plane up is a unique aspect of the instant embodiments. There may be solutions to facilitate partial control-plane response. Most requires a designer to choose what control-plane events to track and respond. Mimic keep-alive packet have been used for selective L2 protocols which are sent on a regular basis from the data-plane. The mimic keep-alive packets prevents a link from going down while control-plane is being upgraded, but because the same static set of packets are repeatedly transmitted irrespective of the peer state, the technique can lead to instability if peer nodes are changed.

Stacking mechanisms provide redundancy but require redundant hardware. Cloud/controller managed switches are completely cloud-managed services with almost a complete separation of control-plane (in the cloud) and data-plane (on the physical device). Examples include OpenFlow and P4 switches. The control-plane runs in the cloud along with a thin protocol layer and drivers while the data-plane run on the physical switch. The protocol layer provides interfaces that can be accessed from cloud applications and controllers. Cloud-managed switches often require comparatively infrequent switch software upgrades, however, if the switch software needs an upgrade, it will suffer the same downtime problems as seen in traditional switches.

Near-hitless operation of core routers is a requirement of most core or backbone operations. The same or similar near-hitless operation requirements are being extended to access and campus networking. Certain real-time factory and distribution control automation may incur substantial financial impact for each minute of network outage. Hospitals and IoT applications may have real-time and life-critical applications, and cannot tolerate network downtime.

Modular platforms (e.g., Cisco Catalyst 9400) are designed and implemented with inherent redundancy having both active and standby supervisors or RP modules handle control-plane. Software upgrade may be done through ISSU with very low data-plane and control-plane impact. Non-redundant switches on the other hand, do not have an active/standby and the software upgrade process is intrusive, impacting data-plane for seconds) and control-plane (for minutes).

Multiply non-redundant switches can be connected and represented as a single larger system and is known as Stacking configuration mode. It could use either back-side or front-side (e.g., SVL) stacking. A stack of switches appears to the rest of the network as one single switch. This makes it easier to manage and configure. Since there is more than one processor sub-system that can host the control-plane, a stacked system has redundancy with ‘active’ and ‘standby’ capable of handling the entire stack on their own. SSO is the mechanism for state synchronization between and active and standby in a redundant system. This can occur in either a modular dual supervisor or a stacked system. This can also provide hitless or near-hitless software upgrade capability for stacked switches.

In general, SSO works by synchronizing startup and running configurations from ‘active’ to ‘standby’. Applications continue to sync all their state data between ‘active’ and ‘standby’ using this mechanism. On a switchover operation (aka, SWO), state reconciliation is not needed since the state has already been kept in sync by the applications.

In the context of software upgrade of a modular or a stacked system, the ‘standby’ unit takes over control-plane processing duties while the ‘active’ upgrades to a different release. This process is commonly referred to as ISSU, and used to either upgrade or downgrade images on platforms that support SSO. This minimizes downtime and degradation of service. During the upgrade process, Active and Standby units will have different versions of software.

While the control plane stays up during ISSU of a stacked system, it may not be able to update the data-plane of the switch during image upgrade, since it is likely that the modules that interact with the active control-plane, as well as the ASIC drivers are also being upgraded.

FIG.8is a diagram showing software upgrade in a stacking system in accordance with an illustrative embodiment. InFIG.8, two switches (“S1” and “S2”) in a stacked configuration are being upgraded from one version of software to another (shown as “16.12.1” to “16.12.2”) using conventional switchover operations. The redundant switch “S2” is powered on and joins the upgrading switch “S1” in stack mode (3) and assumes ‘standby’ role. The upgrading switch “S1” (active node) performs a bulk synchronization operation (2) and subsequently performs an incremental synchronization operation of its control-plane state to the standby node. Both the upgrading and redundant switches “S1” and “S2” are synchronized and have the same control-plane state. The upgrading switch “S1” then starts the software upgrade, which leads to redundant switch “S2” assuming the ‘active’ role. Subsequently the host-CPU on the upgrading switch “S1” goes through reboot (12&14). When the upgrading switch “S1” is booted up with the new 16.12.2 image, it assumes the ‘standby’ role (18). The redundant switch “S2”, which is playing ‘active’ role, then performs the control-plane synchronization to the upgrading switch “S1” (22). Once the upgrading switch “S1” has completed its upgrade, the redundant switch “S2” starts its upgrade (26), and a similar process is applied on the redundant switch “S2” (steps26through40). Subsequently, both the upgrading switch “S1” and redundant switch “S2” are upgraded from versions 16.12.1 to 16.12.2.

In contrast to such operation, the exemplary system and method provides for the dynamic creation and deletion of a remote virtual switch. The exemplary system and method may involve stack formation between physical and virtual switches where the physical switch may be a non-redundant device (i.e., a standalone device). The exemplary system and method may employ control-plane state synchronization across physical and virtual switches. The exemplary system and method may use virtual switch to manage the data-plane device (Switching ASIC, NPU, etc.) state of the physical switch, while the control-plane is upgrading. The exemplary system and method may update data-plane state of the physical switch even during the upgrade process. For example, newly learnt MAC entries can be configured, LACP can update EtherChannel membership, among others. The exemplary system and method provides a temporary operation during the software upgrades.

Indeed, non-redundant switches configured with the exemplary system and method can maintain near-hitless control-plane operation during the entire upgrade process, which in turn helps to keep data-plane state up-to-date. In some embodiments, the exemplary system and method is configured to use stacking and HA mechanisms in conjunction with a virtual switch. One or more virtual switches may be spun up in the cloud for a scalable and low-cost mechanism to upgrade a large network.

The exemplary system and method may operate with network management solutions such as DNAC (DNA Center with Assurance) and SWIMS (software image management). HA, such as ISSU, SSO and Stacking technologies are well-proven and readily available on switch platforms. The exemplary system and method, in some embodiments, can use such infrastructures as-is, and extends the infrastructure with i) a logical data-plane interface (vPCI, vAXI, etc.) on embedded micro-controller (M3 on Doppler ASICs), ii) enhancements to run binos/Polaris in a cloud and remote server environments, iii) provides commissioning/decommissioning operation of a ‘virtual switch’ in a stacking configuration. In some embodiments, the exemplary system and method can implement a cache and flush operation for incremental control-plane state updates. Indeed, any updates to the protocol behavior or bootup sequence may be performed without knowledge by the software upgrade process.

Embodiments of the network device may be implemented, in whole or in part, in virtualized or mobile virtualized network hardware in addition to physical hardware.

Although exemplary implementations may refer to utilizing aspects of the presently disclosed subject matter in the context of one or more stand-alone computer systems, the subject matter is not so limited, but rather may be implemented in connection with any computing environment, such as a network or distributed computing environment. Still further, aspects of the presently disclosed subject matter may be implemented in or across a plurality of processing chips or devices, and storage may similarly be effected across a plurality of devices. While various embodiments of the present disclosure have been described above, it should be understood that they have been presented by way of example only, and not limitation. It will be apparent to persons skilled in the relevant art that various changes in form and detail can be made therein without departing from the spirit and scope of the present disclosure. Thus, the breadth and scope of the present disclosure should not be limited by any of the above-described exemplary embodiments but should be defined only in accordance with the following claims and their equivalents.