upper protocol ——PMIP

Proxy Mobile IP

Proxy Mobile IP (or PMIP , or Proxy Mobile IPv6 ) is a new standard currently (2008) being worked on at Internet Engineering Task Force (IETF). Sometimes referred to as Network-based mobility management , it provides similar functionality to that of Mobile IP , however it does not require any modifications to the mobile host's network stack, i.e. the mobility is taken care of by the network.

 Introduction

Network-based mobility management enables the same functionality as Mobile IP, without any modifications to the host's TCP/IP Protocol stack . With PMIP the host can change its point-of-attachment to the Internet without changing its IP address . Contrary to Mobile IP approach, this functionality is implemented by the network, which is responsible for tracking the movements of the host and initiating the required mobility signalling on its behalf. However in case the mobility involves different network interfaces, the host needs modifications similar to Mobile IP in order to maintain the same IP address across different interfaces.

  How Proxy Mobile IP works

The standard defines two network entities which are involved in the process - Local Mobility Anchor (LMA) and the Mobile Access Gateway (MAG). Mobile Access Gateway is a function on an access router that manages the mobility related signalling for a mobile host that is attached to its access link. Local Mobility Anchor is the home agent for the mobile host in a Proxy Mobile IP domain.

The protocol works as follows:

• A mobile host enters a PMIP domain
• A Mobile Access Gateway on that link checks host authorization
• A mobile host obtains an IP address
• A Mobile Access Gateway updates a Local Mobility Anchor about the current location of a host
• Both MAG and LMA create a bi-directional tunnel

  See also

• Mobile IP
• Mobile IPv6

  External links

• Proxy Mobile IPv6 IETF draft
• Proxy Mobile IPv6 IETF proposed standard