Configuring a DHCPv6 Relay Agent

A DHCPv6 Relay Agent is configured in the IPv6 DHCP6 context of a group-interface:

config>service>vprn>sub-if>grp-if>ipv6>dhcp6# relay ?
config>service>ies>sub-if>grp-if>ipv6>dhcp6# relay ?
  - no relay
  - relay

 [no] client-applications - Configure the set of DHCP6 relay server client
                            applications
 [no] description     - Description for DHCPv6 relay
 [no] link-address    - Configure the link address of the DHCPv6 relay messages
 [no] option          + Configure the DHCPv6 Relay information options
 [no] server          - Configure the DHCPv6 server IPv6 address
 [no] shutdown        - Administratively enable/
disable DHCPv6 relay on this interface
 [no] source-address  -
 Configure the source IPv6 address of the DHCPv6 relay messages

Up to eight DHCPv6 servers can be provisioned to be served by a DHCPv6 Relay Agent. A Relay-Forward is send to all servers and the Relay-Replies from all servers are sent to the client.

The ‟client-applications” parameter specifies if the Relay Agent can be used for IPoE (dhcp) or PPP (ppp) hosts. Optional configuration parameters:

• description

  A free configurable description string.

• link-address

  The link address field in the DHCPv6 Relay-Forward message header.

  The link address can be configured to enable link-address based pool selection in a 7450 ESS and 7750 SR DHCPv6 local server. The address must be one of the IPv6 prefixes configured at the ipv6 subscriber-prefixes context for a subscriber interface. If not configured, the system selects one of the prefixes.

• option: allows to configure following options to be inserted in the Relay-Forward message:

  • Interface-Id [18]

    The interface ID option identifies the interface on which the DHCPv6 client message is received. The format options are the following:

    • ascii-tuple:

      host-name | service-id | group-interface-name | sap-id

    • ifindex

      Interface index for the group interface

    • sap-id

      SAP identifier (port and VLANs)

    • string <string>

      A free configurable string (up to 80 characters)

  • Remote-Id [37]

    Relay Agent Remote Id option contains the DHCPv6 client DHCP Unique Identifier (DUID).

• source-address: the source-address of the Relay-Forward messages.

  If not configured, the outgoing interface IPv6 address is used. The source-address configuration is mandatory for a DHCP Relay Agent in a VPRN service when the DHCPv6 server is reachable by a tunneled next-hop (MPLS).