Slots for line modules, switch route processor (SRP) modules, and switch fabric module (SFM) modules are located in the front of the router, while slots for input/output adapters (IOAs) and SRP IOAs are located in the rear.
Figure 12: E320 Router, Front View

Figure 13: E320 Router, Rear View

Figure 14: E120 Router, Front View

Figure 15: E120 Router, Rear View

For details about available line modules, IOAs, and compatibility between line modules and SRP modules, see the E120 and E320 Module Guide.