Network Working Group                                              C. Ng
Request for Comments: 4888                      Panasonic Singapore Labs
Category: Informational                                       P. Thubert
                                                           Cisco Systems
                                                               M. Watari
                                                           KDDI R&D Labs
                                                                 F. Zhao
                                                                UC Davis
                                                               July 2007


         Network Mobility Route Optimization Problem Statement

Status of This Memo

   This memo provides information for the Internet community.  It does
   not specify an Internet standard of any kind.  Distribution of this
   memo is unlimited.

Copyright Notice

   Copyright (C) The IETF Trust (2007).

Abstract

   With current Network Mobility (NEMO) Basic Support, all
   communications to and from Mobile Network Nodes must go through the
   bi-directional tunnel established between the Mobile Router and Home
   Agent when the mobile network is away.  This sub-optimal routing
   results in various inefficiencies associated with packet delivery,
   such as increased delay and bottleneck links leading to traffic
   congestion, which can ultimately disrupt all communications to and
   from the Mobile Network Nodes.  Additionally, with nesting of Mobile
   Networks, these inefficiencies get compounded, and stalemate
   conditions may occur in specific dispositions.  This document
   investigates such problems and provides the motivation behind Route
   Optimization (RO) for NEMO.














Ng, et al.                   Informational                      [Page 1]

RFC 4888               NEMO RO Problem Statement               July 2007


Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  3
   2.  NEMO Route Optimization Problem Statement  . . . . . . . . . .  3
     2.1.  Sub-Optimality with NEMO Basic Support . . . . . . . . . .  4
     2.2.  Bottleneck in the Home Network . . . . . . . . . . . . . .  6
     2.3.  Amplified Sub-Optimality in Nested Mobile Networks . . . .  6
     2.4.  Sub-Optimality with Combined Mobile IPv6 Route
           Optimization . . . . . . . . . . . . . . . . . . . . . . .  8
     2.5.  Security Policy Prohibiting Traffic from Visiting Nodes  .  9
     2.6.  Instability of Communications within a Nested Mobile
           Network  . . . . . . . . . . . . . . . . . . . . . . . . .  9