A specification from the ATM Forum (now MFA Forum) for a public network-to-network interface (PNNI) between two ATM-based network service providers or carriers, using permanent virtual circuits (PVCs).The B-ICI specification is based on Broadband ISDN User Part (B-ISUP) signaling messages and parameters. B-ICI includes service-specific functions above the ATM layer required to transport, operate and manage a variety of intercarrier services. See also ATM, FUNI, B-ISDN, MFA Forum, PNNI, and PVC.