Use of the PPAR Scope to Implement IP over Mobile ATM
Original Publication Date: 2001-Apr-13
Included in the Prior Art Database: 2003-Jun-20
1. Introduction The mobility of ATM networks is specified by the ATM Forum with the PNNI mobility extensions. The mechanism allows the logical group node abstracting a mobile ATM network to roam in the PNNI hierarchy of the terrestrial backbone network. Routing information about the current location of a mobile network, is advertised through regular PNNI, thus enabling the setup of calls from a ground end-system to an end-system on board of a mobile platform and vice-versa. The implementation of the an ATM rerouting mechanism for SVCs in addition to the PNNI mobility extensions, makes the complete handling of mobility at layer 2 ATM possible. Proxy Par, also specified at the ATM Forum, allows upper layer protocols (e.g. IP) to register information and get this information flooded by the PNNI protocol. Proxy Par has been designed to allow IP routers at the edge of an ATM cloud to learn about each other, thus avoiding manual configuration of the IP adjacencies of the routers. Routers can register their layer protocol information (e.g. IP address, ATM address, OSPF area) to their serving ATM switch, which floods the information throughout the ATM network. Other routers can retrieve this information by querying their serving ATM switches and initiate for example a BGP session based on the IP and ATM address learned. Proxy Par allows a router to indicate a scope when registering information. The piece of information registered is flooded within the ATM network, up to the PNNI level matching the scope specified.