It is a common design to have an internet Edge router connected to two different internet service providers to protect against the failure of an ISP bringing the office down. The topology may look something like this: The two ISPs
IP services – Notes
ARP Address Resolution Protocol, used to discovery layer two address when IP address is already known. Uses protocol 0x0806 compared to Ethernet which uses 0x0800. At layer two an ARP request is a broadcast since the MAC address of the