Transport Protocol Server Relocation via Session State Decoupling
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Solution Overview
Problem
Existing server relocation methods in transport protocol environments, such as those in 3GPP, face challenges in maintaining session continuity and optimizing data paths during user equipment (UE) mobility, particularly with issues like tromboning and complex state transfer, especially when using anycast IP addressing or unique IP addresses.
Innovation Solution
A method for server relocation that involves initiating a transport protocol path, receiving an offer to take over a session, deciding based on policy rules, and transferring session state information to another server, allowing seamless session continuation with minimal additional network functionality, using protocols like MPTCP or QUIC for efficient path management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If anycast IP addressing is used for server relocation, then server selection flexibility is improved, but session continuity and routing complexity deteriorate due to tromboning effects
Solution Approach 1:
The patent introduces a transport layer mechanism that acts as an intermediary between the IP layer and application layer. This mechanism maintains session continuity by managing endpoint identifiers independently of IP address changes, allowing anycast routing without tromboning effects while preserving session state across server transitions.
Solution Approach 2:
The patent segments the session management function from the IP addressing function. By using transport layer endpoint identifiers separate from IP addresses, the system allows IP layer anycast routing while maintaining application layer session continuity, effectively decoupling routing flexibility from session management complexity.
2Reliability
If unique IP addresses are used for each server, then session continuity is improved, but network infrastructure complexity and state transfer overhead worsen
Solution Approach 1:
The transport layer mechanism serves as an intermediary that manages session state independently of server IP addresses. It maintains session continuity by tracking endpoint identifiers rather than relying on persistent IP addresses, reducing the need for complex network infrastructure changes while preserving session reliability.
Solution Approach 2:
The patent implements efficient state transfer by copying only essential session parameters through the transport layer during server transitions. This selective copying mechanism maintains session continuity without requiring complete state replication, reducing infrastructure complexity while preserving reliability.
3Reliability
If complex state transfer mechanisms are implemented for server relocation, then session continuity is improved, but signaling overhead and relocation complexity worsen
Solution Approach 1:
The patent extracts essential session state information from complex state transfer mechanisms, retaining only critical parameters needed for session continuity. This extraction approach maintains reliability by preserving necessary session context while eliminating unnecessary signaling overhead associated with complete state replication.
Solution Approach 2:
The transport layer implements selective copying of session state parameters during server relocation. By copying only essential information rather than complete session states, the mechanism maintains session continuity while significantly reducing signaling overhead and relocation complexity.
4Speed
If local caching is implemented close to clients, then access speed is improved, but network topology complexity and server management overhead worsen
Solution Approach 1:
The patent implements dynamic server selection at the transport layer that adapts to UE mobility and network conditions. This dynamic mechanism allows content to be served from the closest available server (local cache or origin) without requiring static complex network topology configurations, maintaining access speed while simplifying network management.
Solution Approach 2:
The transport layer mechanism provides universal session management that works across multiple server types (local caches, edge servers, origin servers) without requiring topology-specific configurations. This multi-functionality enables fast local access while simplifying overall network topology management through a unified approach.
Data Source
AI summary
A system and method for managing a server in a packet data network. A transport protocol session is established between a client (20) and server (14_1) to transfer content from the server to the client in data packets. The transport protocol path is assigned an n-tuple identifier, whereupon the server transmits to the client data packets with the n-tuple identifier. The server additionally transmits declarative information as signaling packets with the n-tuple identifier, wherein the declarative information includes an identifier which is specific to the data being transmitted in the ongoing session. This allows other servers (14_2) to receive the signaling packets and detect the data that is being transmitted. If such another server then determines that it also has the same data and is better placed to serve that data to the client, it can offer to take over the session.