IMS Node Blacklisting via Test Message Verification
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Solution Overview
Problem
Current IMS node blacklisting methods result in significant network errors and lost call setups due to delayed detection of error states, causing previously failed hosts to be reinstated before they have fully recovered, leading to repeated blacklisting and increased call failures.
Innovation Solution
Implementing a method where an IMS node is temporarily blacklisted and only returned to service after successfully processing a test message, thereby reducing the time delay in error state detection and minimizing network errors by classifying nodes into blacklisted, normal, and quarantine states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the failed host is removed from the blacklist after a predetermined period, then the blacklist management is automated and simple, but a large number of call setups are lost because the host is still in error state
Solution Approach 1:
The patent applies preliminary action by performing a test message send before removing the host from the blacklist. The CSCF sends a test SIP message to the previously blacklisted host to verify its operational status before reinstating it to service, preventing premature reinstatement of failed hosts and reducing lost call setups
Solution Approach 2:
The patent implements feedback by using the response to the test message to determine whether to remove the host from the blacklist. If the test message is successfully processed, the host is removed from the blacklist; if not, the host remains blacklisted. This feedback mechanism ensures reliable status verification while maintaining automated blacklist management
2Reliability
If the CSCF waits for a long period before removing the host from blacklist, then fewer call setups are lost, but the network availability and service recovery time are reduced
Solution Approach 1:
The test message verification performed before blacklist removal allows the system to safely reduce the predetermined blacklisting period. By verifying host status upfront, the system can remove hosts from the blacklist sooner without risking premature reinstatement, thus reducing service recovery time while maintaining call setup success rate
Solution Approach 2:
The patent replaces the mechanical waiting period approach with an intelligent verification mechanism. Instead of relying on fixed time delays to ensure host recovery, the system uses active test message sending and response verification to dynamically determine when a host is ready for service, optimizing both reliability and recovery time
3Speed
If the CSCF frequently checks the status of blacklisted hosts, then the detection of recovered hosts is faster, but the network traffic and processing overhead increase
Solution Approach 1:
The patent applies periodic action by sending test messages at predetermined intervals rather than continuously monitoring host status. The test message is sent once when the blacklisting period expires, balancing timely detection of recovered hosts with minimized network traffic and processing overhead
Solution Approach 2:
The system uses self-service by leveraging the host's own response to the test message to indicate its operational status. The host itself provides the verification information by successfully or unsuccessfully processing the test message, eliminating the need for continuous active monitoring and reducing overall network overhead
Data Source
AI summary
Accordingly, there is provided an IMS node, comprising a transmission module and a processor. The transmission module is arranged to send SIP messages to a plurality of other IMS nodes. The processor arranged to detect an error in a particular other IMS node, the error indicating that the particular other IMS node is not available to receive traffic. In response to detection of such an error, the processor causes the particular other IMS node not to be used for a period of time. The transmission module is further arranged to send at least one test message to the particular other IMS node when the period of time expires. The processor is further arranged to determine if the at least one test message is successfully processed by the particular other IMS node, and in response to a positive determination then returning the particular other IMS node to use.