hitless upgrade

Is there ever really a good time to perform a network device image upgrade? For many customers, downtime is not an option. They expect that upgrades occur while the network continues to forward packets, without any service impact. Designing a highly redundant network involves several strategies to ensure continuous operation and minimize downtime. Key approaches include multiple network paths between critical points, load balancing, and dual-homed devices and switches. Cisco supported hitless upgrades for data…