Hitless Virtual Router Upgrade via Standby VM Incubation
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Solution Overview
Problem
Conventional methods for upgrading line cards in physical routers result in traffic disruption and require expensive redundant hardware to prevent service interruptions, which is costly and inefficient.
Innovation Solution
The method involves upgrading route processor virtual machines (RP VMs) and line card virtual machines (LC VMs) in a virtualized environment without disrupting data traffic by spawning new VMs, configuring switches to forward traffic to both active and standby VMs, and swapping roles to ensure seamless traffic flow without additional hardware.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional line card upgrade methods are used in physical routers, then image upgrade can be performed, but traffic disruption occurs and redundant hardware is required
Solution Approach 1:
The patent creates a virtual copy of the line card functionality through virtual machine migration. Instead of requiring physical redundant hardware, the system copies the operational state and configuration of the active line card to a standby virtual machine, enabling seamless failover during upgrades without additional physical components.
Solution Approach 2:
The patent replaces the mechanical hardware redundancy system with a software-based virtualization system. By using virtual machines that can be migrated and cloned, the system eliminates the need for duplicate physical line cards while maintaining service continuity during upgrade operations.
2Productivity
If conventional line card upgrade methods are used, then upgrade can be performed, but traffic loss occurs
Solution Approach 1:
The patent performs preliminary actions by pre-configuring standby virtual machines with the new image before the actual upgrade. The standby VM is prepared in advance with the updated software, allowing the active VM to be swapped over instantly during the upgrade process, thus preventing traffic loss while maintaining upgrade speed.
Solution Approach 2:
The patent ensures continuity of useful action by maintaining continuous traffic flow through the virtual router. The standby virtual machine is configured to take over traffic immediately upon activation, eliminating interruptions in data forwarding during the upgrade process and maintaining uninterrupted service.
3Reliability
If redundant hardware is deployed to prevent traffic disruption, then service continuity is improved, but cost increases
Solution Approach 1:
The patent creates a virtual copy of the line card functionality through virtual machine migration. Instead of requiring physical redundant hardware, the system copies the operational state and configuration of the active line card to a standby virtual machine, enabling seamless failover during upgrades without additional physical components.
Solution Approach 2:
The virtual router platform provides multi-functionality by supporting multiple virtual machines that can serve different roles (active, standby, upgraded) on the same physical hardware. This universal platform eliminates the need for dedicated redundant hardware for each upgrade scenario, reducing overall hardware requirements while maintaining service continuity.
Data Source
AI summary
Exemplary methods for upgrading route processor virtual machines (RP VMs) and line card virtual machines (LC VMs) include upgrading a second RP VM serving as a standby RPVM with a new RP VM image. The methods further include spawning, using a new LC VM image, a second set of LC VMs to serve as standby LC VMs. The methods also include performing incubation of standby VMs, by configuring a switch to forward data traffic to both the first and second set of LC VMs, thereby allowing system states of the standby VMs to be auto-populated by the data traffic. The methods further include, after the incubation has completed, swapping roles of VMs at the virtual router, such that data traffic are exchanged only between the switch and the upgraded VMs.