Brocade Multi-Service IronWare Routing Configuration Guide (Supporting R05.6.00) - Manual (Page 459)

Multi-Service IronWare Routing Configuration Guide 431
53-1003033-02
DHCP relay agent for IPv6
This feature description is shown in Figure 33 .
FIGURE 33 DHCPv6 Relay Agent Prefix Delegation Notification
A route is added to the IPv6 route table on the provider edge router (PE) for the delegated prefix to
be delegated to requesting routers. The delegating router chooses a prefix for delegation and
responds with it to the requesting router. to the external network and to enable the correct
forwarding of the IPv6 packets for the delegated IPv6 prefix. Adding the delegated prefix to the IPv6
route table ensures that the unicast Reverse Path Forwarding (uRPF) works correctly.
Since the PE is also a DHCPv6 relay agent (it relays DHCPv6 messages between the CPE and the
DHCP server), it examines all DHCPv6 messages relayed between the CPE and the DHCP server
and gathers information about a delegated prefix and then manages the advertisement of this
delegated prefix to the external network.
DHCPv6 Relay Agent Prefix Delegation Notification limitations
The following limitations apply to the DHCPv6 Relay Agent Prefix Delegation Notification.
• The PD notification fails when the DHCPv6 messages between a DHCPv6 server and a DHCPv6
client containing the PD option are not relayed via the DHCPv6 relay agent.
• If the delegated prefix is released or renewed by the client at the time when the DHCPv6 relay
agent is down or rebooting, then this release or renewal of the delegated prefix will not be
detected by the relay agent.
• If there is no sufficient disk space on a flash disk, then the system may not store all the
delegated prefixes in the IPv6 route table.