On the Nokia 7750 Service Router (SR), Virtual Private Routed Network (VPRN) services utilize Multiprotocol BGP (MP-BGP) to exchange customer routing information between Provider Edge (PE) devices. This is achieved by using the VPN-IPv4 address family (AFI=1, SAFI=128). To enable the exchange of these VPRN routes within a BGP session, the family vpn-ipv4 command must be configured under the BGP group or neighbor context. This command activates the VPN-IPv4 address family for that specific BGP peering, allowing the advertisement and reception of labeled VPN-IPv4 prefixes, which are essential for VPRN service operation.

B, C: The keywords vprn-ipv4 and vprn are not valid address family identifiers within the Nokia SR OS BGP configuration context. The correct identifier is vpn-ipv4.

D, E, F: The command address-family is the syntax used by other network operating systems, such as Cisco IOS. Nokia's SR OS uses the family keyword to configure BGP address families.

1. Nokia 7750 SR OS Services Guide, Release 22.10.R1: In the "Virtual Private Routed Network (VPRN) Services" chapter, the section "VPRN Configuration Overview" details the BGP configuration steps. It explicitly shows the use of the family vpn-ipv4 command to enable the exchange of VPRN routes between PE routers. (See section: "Basic VPRN Configuration" for command examples).

2. Nokia 7750 SR OS Routing Protocols Guide, Release 22.10.R1: The "BGP" chapter, under the "BGP Configuration Overview" and "Configuring BGP" sections, describes the command hierarchy. It specifies that the family command is used at the config>router>bgp>group and config>router>bgp>group>neighbor levels to enable specific address families, including vpn-ipv4.