Section 3: ISDN (8 Points)
Ensure that VLAN3 and R4 Lo0 are accessible from R1 and beyond should the Frame Relay network fail either physically or logically. If VLAN3 and R4 Lo0 networks are restored while the ISDN line is active, ensure that traffic is routed over the Frame Relay network to these destinations immediately.
Configure R1 so that if half of the ISDN traffic to R4 is of an unacceptable quality, the line is automatically disconnected.
Allow only R1 to dial into R4. Do not use any PPP feature in your solution.
Do not allow the ISDN to flap if the Frame Relay network goes up and down; only allow the line to be dropped if the Frame Relay connectivity is deemed to be reliable for 90 seconds.