Quantitative analysis of enhanced mobile IP

Abstract

As the popularity of mobile computing grows, the associated protocols and their scalability are subject to much closer scrutiny. Mobile IP relies heavily on the use of IP-to-IP tunneling, requiring 20 bytes of overhead for every packet routed to or from a mobile node, assuming reverse tunneling is enabled. The goal of this research was to show that Enhanced Mobile IP (EMIP) eliminated the overhead by replacing tunneling with Network Address Port Translation (NAPT) without significantly impacting other performance factors. EMIP was implemented and benchmarks were used to compare EMIP and Mobile IP. The percentage of overhead with EMIP approached zero as the number of packets exchanged increased, while the percentage of overhead with Mobile IP remained constant. Once three or more round-trip packets were exchanged, the overhead of EMIP was less than Mobile IP, and when 1000 round-trip packets were exchanged, EMIP resulted in a bandwidth savings of almost 40,000 bytes. To achieve the bandwidth savings, EMIP introduced a one-time delay in session startup ranging from 160 to 260 ms when compared to Mobile IP, but it does not significantly impact the scalability or overall performance of the protocol. Therefore, the decrease in bandwidth consumed by the overhead of EMIP greatly outweighs the one-time delay and additional memory required.