Cisco Nexus 7000 Series Control Plane Failover
"Throughout both upgrades, we witnessed zero packet loss. After the last major upgrade was completed, we added the business services from the Nexus 5000, still witnessing no loss. We conclude that data center administrators can upgrade their Nexus 7000 gear even during peak hours without users experiencing the negative impact of dropped packets. This obviates the need for the administrator to come in at night or during the weekend in order to [perform] such upgrades, which in turn avoids an extra cost to the provider."
Cisco Nexus 7000 Series In-Service Software Upgrade (ISSU) "The Nexus 7000 kept running a full traffic profile, with zero packets lost, when a line card with an active control plane was physically removed from the switch... Throughout three full repetitions of the test we observed zero packets lost, indicating that a control plane failure in the Nexus 7000 would not induce a negative impact on the end user. That's another useful piece of news for the service provider operating a data center. All Service Provider need are two control planes in each Nexus 7000 switch for both control plane failure conditions and hitless software upgrade."
Cisco Nexus 7000 Series Data Center Convergence "Using the Virtual Port Channel and Virtual Device Context features, Cisco reduces failure times in the data center to less than a second."
Conclusion "Major and minor hitless software upgrades can be accomplished on Cisco's Nexus 7000 Series switches."
"...Make the lives of your operations staff simpler and, with two control plane modules in your data center switches, you will be able to enjoy hitless software upgrades and won't lose valuable services revenues when the control plane fails."
