Implementing a BGP-free ISP core with LISP

Abstract

The sustained growth of the global routing table is exerting an economical strain on ISPs by requiring untimely router upgrades. Notably, it has been speculated that the growth rate of router FIBs is surpassing that of its supporting technology and that the deployment of IPv6 is only to make matters worse. In this paper, we propose LISP-MPS, an architecture based on LISP, that isolates the intra-domain routing of an Autonomous System (AS) from its inter-domain routing. The resulting separation implies the decrease of backbone routing table sizes and enables an AS to control the forwarding of traffic inside its network. For a seamless, cost effective, and incremental deployment, LISP-MPS leverages iBGP to implement the LISP mapping system functionality with minimal modification to a small subset of deployed equipment. Finally, an analysis of realistic topologies shows that, despite changing how packets transit a network, the architecture does not lose resilience to failures. Moreover, we show that it can be a viable alternative to BGP/MPLS deployments due to its low implementation cost.