PGW Anycast Session Routing for Low-Latency International Roaming
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Solution Overview
Problem
Existing communication systems experience delays in international roaming due to the creation of sessions between geographically distant PGWs and SGWs, leading to inefficient routing and potential communication delays, especially when different IP addresses are allocated to each PGW in multiple HPLMNs.
Innovation Solution
Allocating an identical IP address to individual PGWs in multiple HPLMNs using IP Anycast and utilizing the BGP best path selection algorithm to route packets through the shortest distance, along with session information synchronization between databases to ensure redundancy and efficient session creation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If different IP addresses are allocated to each PGW in multiple HPLMNs, then each PGW can be uniquely identified, but communication delays occur due to routing through geographically distant PGWs
Solution Approach 1:
Multiple PGWs in different HPLMNs are assigned the same IP address, merging their identification functions. The PGW in the visited network is selected based on geographical proximity rather than unique IP addressing, thereby reducing communication delay while maintaining reliable session establishment through the SGW's selection mechanism
Solution Approach 2:
The patent applies IP Anycast by copying the same IP address to multiple PGWs in different HPLMNs. This allows the network to use a single IP address identifier while physically distributing PGW instances geographically, enabling the SGW to select the nearest PGW for session establishment and reducing routing distance
2Adaptability or versatility
If sessions are created between geographically distant PGWs and SGWs, then roaming services can be provided across multiple HPLMNs, but transmission delay increases
Solution Approach 1:
The patent introduces dynamic session establishment where the SGW dynamically selects the appropriate PGW based on real-time routing information and geographical proximity rather than pre-establishing fixed distant routes. This dynamic selection optimizes the routing path for each roaming session, reducing transmission delay while maintaining broad roaming service coverage
Solution Approach 2:
The SGW acts as an intermediary that receives session establishment requests from the MN and dynamically selects the optimal PGW based on routing information. This intermediary function allows the system to provide wide roaming coverage while minimizing transmission delay by choosing the nearest available PGW for each session
3Speed
If IP Anycast is used to allocate identical IP addresses to PGWs, then routing through shortest distance is enabled, but session information synchronization becomes critical
Solution Approach 1:
The patent implements feedback mechanisms where PGWs send their existence and capability information to the SGW, and the SGW uses this feedback to select the appropriate PGW for session establishment. This feedback loop enables fast routing decisions while managing the complexity of synchronizing session information across multiple PGWs with identical IP addresses
Data Source
AI summary
Provided is a system including: a first PGW; a second PGW which is located in a network having an ASN different from an ASN of a network in which the first PGW is located and to which an IP address identical to an IP address allocated to the first PGW is allocated; a first storage unit corresponding to the first PGW; and a second storage unit corresponding to the second PGW, wherein the first PGW includes: a request reception unit which receives, from an SGW, a session creation request by a communication terminal; a session information creation unit which creates session information on the communication terminal; and a registration unit which registers, in the first storage unit, the session information, and wherein the system further includes a session information synchronization unit which synchronizes the session information between the first storage unit and the second storage unit.