Centralized Data Path Setup with Distributed Control Messaging
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Solution Overview
Problem
In GMPLS-based communication networks, the lack of synchronization in traffic engineering information leads to signaling failures and slow path establishment due to outdated resource allocation data, resulting in 'signaling crank-back' issues.
Innovation Solution
A method involving a central controller that computes and sends explicit path information to network elements, using both central and distributed control messages to ensure fault tolerance and simultaneous path setup, thereby avoiding signaling crank-back and ensuring traffic engineering constraints are met.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If OSPF-TE protocol is used to propagate topology and traffic engineering information, then network elements can calculate routes satisfying traffic engineering constraints, but the traffic engineering information becomes outdated and unsynchronized, leading to signaling failures
Solution Approach 1:
The patent applies preliminary action by having network elements proactively send Te-Changes messages to update traffic engineering information before it becomes outdated. The controller receives these updates in advance and maintains current topology and resource information, preventing the use of stale data in path calculation and avoiding signaling failures.
Solution Approach 2:
The patent implements feedback mechanisms where network elements continuously send Te-Changes messages to the controller about topology and resource changes. The controller processes these feedback messages and updates its database accordingly, ensuring that path calculation always uses current and accurate traffic engineering information.
2Reliability
If frequent updates of traffic engineering information are performed, then path establishment reliability improves, but the time required for path establishment increases due to multiple signaling exchanges
Solution Approach 1:
The controller performs preliminary path calculation and resource reservation before actual data transmission begins. By pre-computing paths based on current topology and resource information, and pre-reserving resources at network elements, the system avoids time-consuming signaling exchanges during path establishment and reduces overall setup time.
Solution Approach 2:
The patent segments the path establishment process into distinct phases: topology discovery, path calculation, resource reservation, and activation. This segmentation allows each phase to be optimized independently, with topology information updated separately from path computation, enabling more efficient and faster path setup without compromising reliability.
3Productivity
If centralized control is used to compute and manage data paths, then path establishment speed increases, but system complexity increases due to centralized controller coordination
Solution Approach 1:
The patent extracts the complex path computation and resource management functions from individual network elements and consolidates them in a centralized controller. This extraction reduces the processing burden on network elements, simplifies their operation, and enables faster path establishment through centralized coordination while managing system complexity at the controller level.
Solution Approach 2:
The controller acts as an intermediary between path computation and resource allocation functions. It receives path requests, calculates optimal routes, reserves resources, and coordinates activation across multiple network elements. This intermediary role streamlines the overall process, improves path establishment speed, and centralizes complexity management.
4Reliability
If distributed control messages are used alongside central control messages, then fault tolerance improves, but message processing complexity increases
Solution Approach 1:
The patent segments control messages into two distinct types: central control messages from the controller and distributed control messages between network elements. Each type serves specific purposes and can be processed independently. This segmentation simplifies processing by allowing network elements to handle different message types with dedicated logic, reducing overall processing complexity while improving fault tolerance.
Solution Approach 2:
The controller serves as an intermediary that manages the complexity of coordinating both central and distributed control messages. It processes Te-Changes messages, maintains topology information, and ensures consistent state across the network. This intermediary function absorbs the complexity of message coordination, allowing network elements to focus on local processing and improving overall fault tolerance.
Data Source
AI summary
A communication network has a plurality of network elements (NEs) and links between the NEs. A method includes computing, at a central controller, a data path from the source NE to the destination NE along a number of intermediate NEs, sending, from the central controller, central control messages to all or at least a plurality of NEs among the source NE, the intermediate NEs and the destination NE, the central control messages including explicit path information, the explicit path information in at last some of the central control messages comprising more information than needed by the recipient NE for its set-up for data transport along the path, and sending distributed control messages between NEs of the path, the distributed control messages being based on at least one central control message received by one of the NEs.