DHCPv6 IA_NA can be used for IPv6 WAN address assignment. IPv6 WAN prefix can also be supported using SLAAC.
For DHCPv4, the following address allocation modes are supported.
DHCPv4 proxy
The IPv4 address offered in DHCPv4 from the RG can be provided from AAA during initial authentication in the framed-IP-address RADIUS attribute.
DHCPv4 relay to a local or external DHCPv4 server for IPv4 address allocation
The pool can be provided from AAA during initial authentication in the framed-pool RADIUS attribute, and can be added in the relayed DHCP packets with a DHCP Option 82 vendor-specific sub-option.
For DHCPv6, the following address allocation modes are supported.
DHCPv6 proxy
The /128 IPv6 address for RG WAN using DHCPv6 IA_NA can be provided from AAA during initial authentication in Alc-IPv6-address VSA. The PD prefix requested by RG using DHCPv6 IA_PD can be provided from AAA in the Delegated-IPv6-Prefix RADIUS attribute.
DHCPv6 relay to a local or external DHCPv6 server for IPv6 address and prefix allocation
The pool for /128 IPv6 address allocation for DHCPv6 IA_NA can be provided by AAA during initial authentication in the framed-ipv6-pool attribute. Pool for PD prefix can be provided by AAA during initial authentication in the Alc-Delegated-IPv6-Pool VSA. These are signaled by DHCPv6 relay to the server.
Authentication is performed only during GTP session setup. All the RADIUS attributes related to DHCP and IP stack (host) setup are received during this authentication. No subsequent authentication is performed on the receiving DHCP. A single IPoE session containing all the hosts (DHCPv4, DHCPv6 IA_NA, and SLAAC) are created per GTP session. PD prefix should be configured to be added as a managed-route if both DHCPv6 IA_NA and SLAAC are in use and creating respective hosts.
Figure: Call flow for GTP session setup shows the call flow for GTP session setup, subsequent DHCP exchange, and host creation in case of RG with a standalone modem (user equipment is noted as UE in the diagram).
DHCP over GTP-u tunnel is not supported in conjunction with bonding (hybrid-access).
DHCP over GTP-u tunnel is supported in conjunction with multiple APNs. The APNs can have different address management (for example, in case of two APNs). It is possible to use WAN address assignment using NAS for one APN and DHCPv4 for another APN.
Broadcast flag should not be set in DHCP messages from the client.