Abstract: The current mobile IP specification forces all packets forwarded to a mobile terminal (MT) to be routed via that terminal's home agent (HA), which often leads to triangular routing, which in turn causes data transmission delay and wastes network resources. IETF (Internet Engineering Task Force) is studying a solution that can optimize the route length, but this solution requires the implementation of additional functions on all correspondent nodes, so it will not be realistic. The paper proposes the use of mobile IP border gateways (MBGs) to optimize the routing in a carrier-scale network and reduce the processing burden on the HA without adding more functions to the correspondent nodes, and shows the effect of reducing the route length and the HA's load. We also propose a hierarchical arrangement of foreign agents (FAs) to reduce the processing burden on MBGs.