IP gateway, services, and routing

In many deployments, a BNG UPF acts as a direct IP gateway for sessions. All IP addresses are allocated by the BNG CPF and installed using the PFCP protocol. Optionally, framed routes can be provided by the BNG CPF.

To assist with forwarding, the BNG CPF signals the following information using the PFCP protocol.

• The service in which forwarding must occur is a name that maps to a preprovisioned IES or VPRN service.

• The aggregate routes that the BNG UPF can announce in routing protocols to attract traffic can be distinguished in policies using the direct option for the protocol name in the configure policy-options policy-statement entry from protocol name context.

  Note: The BNG CPF guarantees that no addresses from the aggregate routes are assigned to sessions on another BNG UPF. See the 7450 ESS, 7750 SR, 7950 XRS, and VSR Unicast Routing Protocols Guide for more information about route policies.

• The gateway address for IPv4 is typically a dedicated address within the aggregate route, and for IPv6 it is a link-local address, only one of which per VPRN or per IES is supported for IPv6.

  The BNG UPF still runs the appropriate routing protocols and responds to ARP/ND for the gateway addresses.