Issues in the Usage of MANETs as Backup or Load-Balancing Transit Networks of the Internet

Internetworking the mobile ad-hoc networks (MANETs) with the Internet has been a hot issue for many years. However, most researches have been concentrated on the use of MANETs as the access networks for the Internet. This paper introduces another use of MANETs: backup or load-balancing transit networks for the Internet. Although the MANETs capacity is currently low compared with other backbone technologies, we argue that MANETs is a suitable alternative for backup or load-balancing transit networks of the Internet based on its self-organized infrastructure-less multi-hop architecture and its increasing capacity in the near future. To provide the backup or load-balancing transit services for the Internet, a scalable, stable, lowoverhead, QoS-support ad-hoc routing architecture with the address auto-configuration is required. Moreover, how an Internet gateway selects an external route via MANETs to another autonomous system (AS) also needs to be solved. In this paper, BGP-GCR+, a combination of the border gateway protocol (BGP), the gravitational cluster routing (GCR), and the passive/weak IPv6-based address stateless auto-configuration, is developed towards the standards to achieve the required functions. We have implemented of the routing component of our proposed BGP-GCR+ routing architecture [1] into ns-2 for the performance evaluation. Results show that the packet delivery ratio under high traffic load and mobility in BGPGCR+ is lower than that in AODV-Hello for small-scale (50-150 nodes), but slightly higher for the medium-scale (200 nodes) MANETs. For lower mobility and traffic load, the performance of both BGP-GCR+ and AODV-Hello are high (over 90%). Moreover, the routing overhead is much lower (almost one-half) in BGP-GCR+ compared with AODV in all test cases. The implementation of other components of BGP-GCR+ in ns-2 and the mapping of medium access control (MAC)-related metrics into the link stability of the cluster construction in BGP-GCR+ for quality of service (QoS) support, their performance evaluations are subject to our future researches.