Hub and Spoke BGP: Leveraging multicast to improve wireless inter-domain routing

Satellite payloads and wireless cell/broadband towers are being designed and deployed to simultaneously provide backbone network connectivity for hundreds to thousands of end-user networks. Hence, large wireless “hub and spoke” networks are created. In order to allow user-networks to utilize their own IP address space, hub nodes must distribute user routes throughout the hub and spoke network utilizing a common network routing protocol such as Border Gateway Protocol (BGP). RFC 4271 compliant BGP, also known as BGPv4, is not optimized to take advantage of the multicast capabilities of a wireless channel. In this paper we show that given a wireless hub and spoke network running BGP with N spokes, system wide bandwidth savings from O(N2) to O(N) can be gained through multicasting the BGP routing messages. We will first present an analytical model with equations that explain our hypothesis, and then introduce a multicast version of BGP called Hub and Spoke BGP. We present a comparison study of large scale hub and spoke emulations utilizing both standard BGP and our multicast-capable version, validating the bandwidth savings.1 2