ATM networks often carry other popular communication protocols such as TCP/IP. LAN emulation techniques, with LANE and MPOA being the most prominent ones, make it possible to support existing applications, but do not take advantage of many ATM capabilities. Furthermore, such server-based solutions often suffer from a single point of failure problems. PNNI augmented routing (PAR), based on private network-network interface (PNNI), enables ATM and TCP/IP to be better integrated than in an emulation environment. In addition to that, proxy PAR has been introduced as minimal version of PAR that gives ATM attached devices the ability to interact with PNNI devices without the complexity associated with a full PAR implementation. Proxy PAR has been conceived as a client/server interaction in which the client side is much simpler than the server side, permitting fast implementation and deployment in existing IPv4 devices. The main purpose of proxy PAR is to allow non-ATM devices to use the flooding mechanisms provided by PNNI for registration and automatic discovery of services offered. Proxy PAR capable servers support filtering based on virtual private network (VPN) IDs, IP protocols and address prefixes. This enables, for example, routers in a certain VPN running OSPF to find their neighboring routers without the manual configuration implied by other technologies such as frame relay.
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