Ensuring Adjacent Device Traffic Redirection

B.

When a Session Border Controller (SBC) fails over, it is necessary to ensure that adjacent devices can redirect their Ethernet traffic to the new SBC that has taken over. This process can be achieved through the use of a mechanism known as Gratuitous ARP.

Gratuitous ARP is an Address Resolution Protocol (ARP) packet that is sent by a device to announce its IP address to other devices on the network. It is used to update the ARP caches of other devices on the network, allowing them to redirect their traffic to the new SBC that has taken over.

When a new SBC takes over, it sends a Gratuitous ARP packet that contains its MAC address and IP address. This packet is broadcast to all devices on the network, and the ARP caches of these devices are updated with the new information. This allows the adjacent devices to redirect their Ethernet traffic to the new SBC, ensuring that there is no disruption to the flow of traffic.

Reverse ARP (RARP) is another protocol that is used to map a MAC address to an IP address, but it is not typically used for failover scenarios. Proxy ARP is a technique that allows a device to respond to ARP requests on behalf of another device, but it is not used in this scenario either.

Hot Standby Router Protocol (HSRP) is a Cisco proprietary protocol that is used to provide redundancy for IP networks. It is typically used in router failover scenarios, not for Session Border Controller failover. Bootstrap Protocol (BOOTP) is a protocol that is used to assign IP addresses to devices on a network, but it is not used in failover scenarios.

In summary, the correct answer to the question is A. Gratuitous ARP is used to ensure adjacent devices can redirect their Ethernet traffic to the Session Border Controller that takes over, when a Session Border Controllers fails over.