Dell PowerConnect 7048P User Manual - Page 144

If you move the master unit of stack to a different place in the network, make sure you power down the whole stack before you redeploy the master unit so that the stack members do not continue to use the MAC address of the redeployed switch. NSF Network Design Considerations You can design your network to take maximum advantage of NSF. For example, by distributing a LAG's member ports across multiple units, the stack can quickly switch traffic from a port on a failed unit to a port on a surviving unit. When a unit fails, the forwarding plane of surviving units removes LAG members on the failed unit so that it only forwards traffic onto LAG members that remain up. If a LAG is left with no active members, the LAG goes down. To prevent a LAG from going down, configure LAGs with members on multiple units within the stack, when possible. If a stack unit fails, the system can continue to forward on the remaining members of the stack. If your switch stack performs VLAN routing, another way to take advantage of NSF is to configure multiple "best paths" to the same destination on different stack members. If a unit fails, the forwarding plane removes Equal Cost Multipath (ECMP) next hops on the failed unit from all unicast forwarding table entries. If the cleanup leaves a route without any next hops, the route is deleted. The forwarding plane only selects ECMP next hops on surviving units. For this reason, try to distribute links providing ECMP paths across multiple stack units. Why is Stacking Needed? Stacking increases port count without requiring additional configuration. If you have multiple PowerConnect switches, stacking them helps make management of the switches easier because you configure the stack as a single unit and do not need to configure individual switches. 144 Managing a Switch Stack