Address Allocation Methods for Different Users

Address Allocation for PPPoX Users

PPPoX users obtain IP addresses through different method in the IPv4 network.

Over an IPv4 network, a PPP user obtains an IPv4 address through one of the following methods:

• After successful authentication, the AAA server allocates an IP address to the user.

• After successful authentication, the AAA server specifies the address pool for the user. The NetEngine 8000 F then assigns an IP address from the specified address pool to the user.

• After successful authentication, the NetEngine 8000 F assigns an IP address from the address pool specified in the domain configuration.

When local address pools are used, the NetEngine 8000 F checks whether there are unused IP addresses in the local address pools. If an unused IP address is found, the NetEngine 8000 F assigns an IP address to the user.

When remote address pools are used, the NetEngine 8000 F functions as the DHCP client to apply for an IP address to the external DHCP server.

• In the NetEngine 8000 F, the PPP protocol supports the negotiation of extended option 144 during the IPCP negotiation. Therefore, the PPP client can obtain the network segment through the IPCP negotiation, and the gateway address and route of the network segment must be delivered by the RADIUS server.

Address Allocation for IPoX users

IPoX users obtain IP address using one of the following methods:

• The NetEngine 8000 F allocate static IP address to static users who use fixed addresses.

• Users obtain IP addresses through DHCP.

  • If the local address pool is configured in the user domain, the NetEngine 8000 F functions as the DHCP server to allocate addresses to users.

  • If the remote address pool is configured in the user domain, the NetEngine 8000 F functions as the DHCP relay to apply for IP addresses to the DHCP server.

• IPv4 address allocation for E-line users

  Layer 2 users obtain IPv4 addresses from a local address pool or remote address pool using DHCP.

  Service packets of Layer 3 users do not travel through the BRAS, and the IP addresses of the Layer 3 users are allocated by other devices.

• Address allocation by the RADIUS server

  • Framed-IP-Address attribute

    The IP addresses allocated for Layer 2 DHCP users must be within the address pool configured. The Layer 2 users can also obtain other information, such as the lease time, from the address pool.

    The IP addresses allocated for Layer 3 DHCP users can be outside of the address pool of the device.

    Multiple IP addresses can be allocated to a user simultaneously, but only the last one takes effect.

  • Framed-Pool or HW-Framed-Pool attribute

    The BRAS allocates IP addresses based on the address pool configured for the user domain.