# Before You Begin

Before installing E Series routers, be sure you:

- Have a plan for installing the routers that takes into consideration future expansion of your system.
- Have the tools and accessories needed to complete the installation.
- Read and understand the clearance requirements for the front and back of the chassis for cable routing and other unit access. See Environmental Requirements for more information.
- Read and understand the clearance requirements for the chassis to ensure adequate ventilation.
- Prepare the equipment racks by measuring and marking space for each router and plenum you plan to install.