A DHCPv6 Relay Agent can support a 7450 ESS and 7750 SR DHCPv6 local server (same or remote chassis) and a third party DHCPv6 external server.
An incoming DHCPv6 client message is relayed within the Relay-Forward message specified in RFC 3315, Dynamic Host Configuration Protocol for IPv6 (DHCPv6). If the server responds with a valid address/prefix, the ESM process attempts to install it. If it fails, the DHCPv6 Relay Agent sends an explicit RELEASE to the server. There is no retransmission of DHCPv6 Relay-Forwards in the case of failure, it requires the client to re-start or re-send the original DHCPv6 message.
A Lightweight DHCPv6 Relay Agent may insert Relay Agent Information including the Interface ID option between the DHCPv6 client and the DHCPv6 Relay Agent.
Additional Relay Agents (non-LDRA) between the DHCPv6 client and the DHCPv6 Relay Agent are not supported.
DHCPv6 Reconfigure messages received from an external DHCPv6 server are forwarded to the DHCP client, if a corresponding DHCPv6 lease exists. The Reconfigure message can be sent in a unicast message to the client or encapsulated in a Relay-Reply message to the DHCPv6 relay agent. The DHCPv6 Reconfigure message is dropped if no corresponding DHCPv6 lease exists.