IP ROUTER FAULT TOLERANCE IN THE iDEN PACKET DATA SYSTEM
Original Publication Date: 1997-Sep-01
Included in the Prior Art Database: 2002-Jun-06
The Packet Data feature within the iDEN system will be implemented using Mobile IP [RFC 20021. Mobile IP specifies the use of a Foreign Agent which provides tunnel endpoints for IP-in-IP encapsulated datagrams. In this system, the foreign network will correspond to an iDEN network. Each foreign agent may have several end- points and each of these endpoints correspond to IP networks. In the iDEN system, encapsulated datagrams that are delivered to these networks will be decapsulated at the foreign agent and will be delivered to Mobile IP hosts (subscriber units) using iDEN specific network and datalink mechanisms. In a large iDEN system, there will be multiple foreign agents each supporting multiple IP network end- points These IP networks must be advertised using a Router Interface Protocol just as any standard IP network would. Furthermore, these IP networks and their corresponding foreign agents must support a high degree of redundancy and fault tolerance. The iDEN system has adopted an N + 1 redundancy scheme for the foreign agents. Furthermore, the iDEN system will utilize standard routing protocols in unique ways to enhance IP network reachability and fault recovery. To meet the reliability require- ments of the iDEN packet data system, the Network Management function and IP network routing protocols must interact. This publication describes this interaction as well as unique techniques for IP advertising.