For any of you wondering what a network backbone is:
The network backbone at many large sites -where networks can span multiple buildings-usually undergoes many minor upgrades in its lifetime. Most often, the upgrades are simple : You add parts to the backbone, such as additional interface cards in routers or switches.
The simplest upgrade is to add "more of the same." A more radical upgrade has you replacing the router or switch with newer devices of the same general type, perhaps replacing some smaller devices with fewer larger ones. Or you might change the technology of a backbone network, retaining the same backbone routers or switches. In these cases, everything outside the backbone remains the same, and with planning, the disturbance to users and system administrators is minimized.
The most radical upgrade would be to replace routers with switches (or vice versa), to deploy ATM as the primary backbone or to deploy virtual LANs (VLANs) widely, for example. These types of changes require modifications to the configuration of every computer on the network. The network and system changes must be coordinated, requiring extensive work with system administrators. With luck, you might find some lengthy down time and enlist all the system administrators in order to accomplish the necessary changes at once. But, more likely, you'll make the changes over time, moving the network and systems to the new scheme LAN by LAN.
Why you would update your backbone:
To address poor performance
To gain superior performance
To provide the performance required by new applications
To provide the performance required by planned expansion
To increase the reliability of the network
This is a great explanation of why we will wait patiently for this maintenance period.