AAA Server Congestion Control via Hint Indicators
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Solution Overview
Problem
Existing congestion control methods in data communications networks are inadequate for handling overload situations, particularly when multiple request/response pairs are involved, leading to resource wastage and increased network traffic.
Innovation Solution
A method for congestion control at AAA servers that includes embedding a 'hint' indicator in response messages to prioritize subsequent messages, allowing the server to manage congestion by identifying and processing messages based on their priority within ongoing sessions, and tracking message exchange rounds to optimize processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the server uses existing algorithms for determining which messages to drop, then the server can handle overload situations, but messages being dropped part way through the exchange force the client to restart the exchange from the beginning, wasting resources and increasing network traffic
Solution Approach 1:
The server embeds a hint indicator in response messages before congestion occurs, allowing the client to prepare for potential message drops. When congestion is detected, the client can resume the exchange from the point where the hint indicator was received rather than restarting from the beginning, thus preventing resource wastage while maintaining exchange completion reliability
Solution Approach 2:
The hint indicator acts as feedback information that travels from server to client and back, enabling the client to understand the server's congestion state and adjust its behavior accordingly. This feedback mechanism allows the client to make informed decisions about message transmission and exchange resumption, reducing unnecessary retransmissions and resource consumption
2Reliability
If the server drops messages when overloaded, then the server can prevent complete system failure, but this introduces additional messages into the network as clients restart exchanges, further worsening the congestion problem
Solution Approach 1:
By embedding the hint indicator in advance in response messages, the server prepares the client for potential congestion scenarios before they fully manifest. This allows the client to maintain exchange state information and resume efficiently when congestion occurs, preventing the proliferation of restart messages that would otherwise worsen network traffic
Solution Approach 2:
The hint indicator changes the parameter of message exchange state tracking, allowing the client to monitor progress through the exchange and resume from specific points rather than restarting. This parameter change reduces the quantity of messages needed to complete exchanges during congestion while maintaining server stability
Data Source
AI summary
Methods for congestion control by a AAA server are provided. In an embodiment of the invention a hint indicator is embedded in reply messages from a AAA server. In subsequent messages received by that AAA server, the AAA server determines when the hint indicator is present. Processing decisions for the subsequent message are based on the presence of the hint indicator. In another embodiment, a method for congestion control at the AAA server is provided. At the AAA server a message received from a network access server is stored and timestamped in an ingress message queue. A congestion state for the AAA server is determined based on an ingress queue state and a message age state. The message is processed based on the congestion state. In alternative embodiments, message processing is based on the congestion state, message type and number of round trip messages.