Traffic Engineering Database Path Computation Update
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Solution Overview
Problem
In data networks, the delay in updating link state information due to regular refresh times in routing protocols like OSPF leads to potential computation of bad network paths in case of link failures or other critical state modifications, resulting in deteriorated network performance.
Innovation Solution
Implementing a method where second link state information is sent on an ad-hoc basis using RSVP-TE or PCEP messages to update the traffic engineering database, allowing for immediate incorporation of critical state modifications, such as link failures, into path computation, thereby reducing the reliance on outdated information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If link state information is updated regularly using routing protocol refresh times, then the routing protocol operates stably, but the path computation uses outdated information in case of link failures
Solution Approach 1:
The system performs preliminary actions by sending link state notify messages proactively when changes are detected at network edges, rather than waiting for the next scheduled refresh. This allows the TED to be updated in advance of the regular refresh cycle, ensuring path computation uses current information.
Solution Approach 2:
A feedback mechanism is implemented where link state changes detected at edge routers are immediately communicated back to the PCE through notify messages. This feedback loop ensures the path computation element receives real-time information about link state changes, allowing it to recalculate paths based on current network conditions.
2Reliability
If the update refresh time is reduced to improve path computation accuracy, then link state information is more current, but scalability problems and routing loop problems increase
Solution Approach 1:
The invention extracts the real-time link state notification function from the regular routing protocol refresh mechanism. By separating this function into dedicated notify messages sent only when changes occur, it avoids the need to reduce the overall refresh time while still achieving current information updates.
Solution Approach 2:
Instead of continuous or frequent periodic updates, the system uses event-driven periodic action where notify messages are sent only when link state changes are detected. This maintains information freshness without the overhead of reduced refresh intervals, avoiding scalability and routing loop issues.
3Productivity
If ad-hoc link state information is sent immediately upon detection, then path computation uses latest information, but network message traffic increases
Solution Approach 1:
The system applies partial action by sending notify messages selectively only for relevant link state changes that affect path computation, rather than broadcasting all network traffic updates. This reduces unnecessary message traffic while still providing timely information for path establishment.
Data Source
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AI summary
A method of establishing a path between nodes (2.1 - 2.4) in a data network (1) involving computing a network path from link state information comprised in a traffic engineering database (TED). The traffic engineering database stores first link state information provided on a regular basis in accordance with a routing protocol used by said data network. The proposed method comprises providing a number of entities (3.1 - 3.4) of said data network used for computing said network path with second link state information sent between peers of nodes (2.1 - 2.4) in the data network on an ad-hoc basis, and using said first and second link state information for computing said network path.