GGSN Packet Routing for Mobile IP Contexts
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Solution Overview
Problem
In GPRS networks, data packets from mobile nodes using Mobile IP protocols may be dropped due to the GGSN not recognizing the new Care Of Address (CoA) or Co-located Care Of Address (CoCoA) as the source address, leading to issues with packet routing and binding updates, especially when multiple PDP contexts are established.
Innovation Solution
A method where the mobile node includes its home address in a Hop-by-Hop Options extension header or Destination Option header of data packets and binding updates, allowing the GGSN to match and route packets to the appropriate PDP context, even when the CoA or CoCoA is used as the source address, and modifying TFTs to include the CoA or CoCoA for future packet filtering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the GGSN uses traditional packet filtering based on source address, then packet routing is simple, but packets from mobile nodes using Mobile IP are dropped because the CoA or CoCoA is not recognized
Solution Approach 1:
The packet filter criteria are made dynamic by allowing the GGSN to recognize both traditional source addresses and Mobile IP addresses (CoA/CoCoA). The system adapts its filtering behavior based on the address type, maintaining simple filtering for normal packets while adding Mobile IP awareness when needed to prevent packet drops.
Solution Approach 2:
The packet filtering parameters are extended to include Mobile IP address formats (CoA and CoCoA) alongside traditional source address filtering. This parameter expansion enables the GGSN to match packets from mobile nodes in different network locations without dropping them, resolving the reliability issue.
2Measurement precision
If the mobile node includes home address in extension headers, then packet routing accuracy is improved, but packet header size increases
Solution Approach 1:
The solution applies partial action by including the home address only in specific extension headers (Hop-by-Hop Options or Destination Option) rather than modifying all packet headers. This selective inclusion provides sufficient routing information for accurate packet delivery while minimizing the increase in header size.
Solution Approach 2:
The extension headers act as intermediaries that carry the home address information. Instead of modifying the core packet structure, these optional headers serve as a mediator to convey additional routing information, achieving accurate packet routing with minimal overhead.
3Adaptability or versatility
If multiple PDP contexts are established, then service flexibility is improved, but packet routing complexity increases due to multiple filters
Solution Approach 1:
The packet filtering function is segmented into multiple independent PDP contexts, each with its own packet filters. This segmentation allows the system to maintain service flexibility by supporting multiple concurrent contexts while managing complexity through modular filter management for each context.
Solution Approach 2:
The system performs preliminary action by pre-configuring packet filters for multiple PDP contexts before mobile nodes arrive. This allows the GGSN to have ready-made filtering rules for different services, reducing real-time routing complexity when packets arrive while maintaining service flexibility.
Data Source
AI summary
Apparatus for and methods of enabling a gateway node of a first packet-switched data network to select a first channel for transferring a data packet to a destination packet data protocol address of a correspondent node provided service in the first network are disclosed. The gateway node is configured to select the first channel from a plurality of channels configured to transfer data packets to the destination packet data protocol address of the correspondent node, wherein the data packet is sent from a mobile node of a second packet-switched data network external to the first network, and wherein the mobile node has been in a communication session with the correspondent node while provided service in a third packet-switched data network different to the second network.