Method and apparatus for route optimisation in nested mobile networks

Abstract

A method of transmitting at least one data packet from a communication node in a data communication network. The method includes receiving (920) a request at a communication node, to transmit at least one data packet to a first destination address and searching (930) for the (first) destination address in a cache of the communication node. A determination (960) of an intermediary address of the destination address is made. The destination address is then replaced with the intermediary address and the steps of searching, determining and replacing are repeated, until no new intermediary address is found. The at least one data packet is then transmit (970) to the destination address via the identified intermediary address(es). A communication unit (corresponding node) communication message and method for building a linked binding cache are also described. In this manner, an optimised data path is determined in order to send at least one data packet to an intended recipient, for example in a nested mobile network scenario.

Description

FIELD OF THE INVENTION [0001] This invention relates to telecommunication systems in which data flows between mobile nodes, for example personal digital assistants with wireless communication capability, and a data network, for example the Internet. BACKGROUND OF THE INVENTION [0002] The Internet is becoming more and more popular, and users increasingly wish to access the Internet whilst on the move. Different types of mobile nodes (i.e. mobile communication units) may be employed for this purpose, for example a mobile telephone or a personal digital assistant (PDA) with wireless communication capability. [0003] Increasingly, mobile users are accessing the Internet via different types of fixed or wireless access networks, for example a cellular radio communication network, such as a Universal Mobile Telecommunication System (UMTS) network, a HiperLAN / 2 or IEEE 802.11b local area network, a Bluetooth local communication system, or fixed accesses such as the Ethernet, and so on. The d...

AI Technical Summary

Benefits of technology

[0030] In contrast, the MR Prefix is bound with the MR care-of address, for a particular MR. Upon reception of a packet whose prefix matches with the MR prefix, the Home Agent must then tunnel the packet to the MR care-of-address that has been identified as being able to deliver the

Problems solved by technology

The lack of knowledge of a true location of a particular MNN results from the HA not knowing any (never mind a preferred) data route to the Mobile Network, once it has moved to a ‘visited’ location.

Unfortunately, when a MR registers with its HA the MR only informs the HA to record a host-specific route in its routing table.

However, it has also been determined that IPv4 does not support route optimisation for MNNs behind the MR.

This problem is exacerbated in the case of nested mobility, which is where a CN wishes to pass data to a MNN that is behind a number of MR links, or a mobile node visiting a mobile network.

This is clearly inefficient routing.

Clearly, the solution proposed does not provide any support for route optimisation, since both inbound and outbound packets are routed through the Home Agent of both MRs 150, 260.

Once again, this is cl

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