each Ex3200 Switch Supports Optional Front-panel Ex-um-2x4sfp Uplink Module With Pluggable Optics For High-speed Backbone Or Link-aggregation Connections Between Wiring Closets And Upstream Aggregation Switches. Ex-um-2x4sfp Uplink Module Can Be Installed Without Powering Down The Switch, Enabling Users To Add High-speed Connectivity At Any Time Or To Migrate From Gbe To 10 Gbe Uplinks, Delivering The Ultimate In Flexible, High-performance Interconnectivity.