Nokia Triple Play Services
Question No. 1
A DHCP relay agent is configured on a BNG when the DHCP server that is serving the client is on a different subnet.
The DHCP relay agent converts the DHCP Discover message to a multicast packet destined to the "All DHCP Servers" address.
The source IP address of the packet destined to the DHCP server is the address of the relay agent.
When the DHCP server replies with an Offer message, it contains the gateway address information.