Hierarchical routing by PNNI and OSPF/BGP

Private Network-Network Interface (PNNI) is a routing protocol standard developed by the ATM Forum for the connection-oriented ATM networking technology. Open Shortest Path First (OSPF) and Border Gateway Protocol (BGP) are the corresponding IETF standards for connectionless IP networks. In this paper, we compare the hierarchical routing properties of these two sets of routing protocols.