PE Router Cross-Domain Fault Tracing Ethernet MPLS
Solution Overview
Problem
Current fault management techniques, such as Ethernet CFM, are inadequate for tracing faults in multi-tiered networks that combine switched Ethernet and MPLS, as they fail to effectively identify errors within the MPLS network, leading to ambiguity in determining the location of issues.
Innovation Solution
A provider edge router interfaces Ethernet and MPLS networks, initiating an MPLS trace session in response to a link trace message, translating MPLS trace replies into a link trace reply message to be sent back to the originating Ethernet node, enabling the tracing of link or node errors within the MPLS network.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Ethernet CFM is used for fault management in multi-tiered networks, then fault management is standardized for Ethernet networks, but it cannot effectively identify errors within MPLS networks leading to ambiguity in determining fault location
Solution Approach 1:
The PE router acts as an intermediary between Ethernet CFM and MPLS OAM protocols. It receives LTM messages from Ethernet nodes, translates them into MPLS trace messages, and translates MPLS trace replies back into LTR messages for Ethernet nodes. This intermediary function enables cross-domain fault tracing while maintaining protocol compatibility, resolving the contradiction between standardized Ethernet fault management and accurate MPLS fault location identification.
Solution Approach 2:
The invention changes the operational parameters of fault management by initiating MPLS trace sessions with specific parameters (such as trace target addresses and timeout values) when receiving LTM messages. This parameter adaptation allows the system to optimize fault tracing for MPLS network conditions while maintaining compatibility with Ethernet CFM standards, thereby improving both reliability and measurement precision.
2Measurement precision
If a PE router initiates MPLS trace sessions for every LTM message, then fault tracing capability in MPLS networks is enhanced, but device complexity and processing overhead increase
Solution Approach 1:
The PE router is designed with multi-functionality to handle both Ethernet CFM protocols and MPLS OAM protocols simultaneously. It can translate between different protocol formats, manage multiple trace sessions, and maintain state information for various virtual private LAN services. This universal design consolidates multiple fault management functions into a single device, enhancing measurement precision without proportionally increasing device complexity.
Solution Approach 2:
The PE router performs preliminary actions by pre-establishing MPLS label switched paths and maintaining forwarding state information before fault tracing is needed. When an LTM message arrives, the PE router can quickly initiate MPLS trace sessions using pre-configured parameters and paths, reducing the processing complexity during actual fault tracing operations while maintaining high measurement precision.
3Adaptability or versatility
If MPLS trace messages are translated from LTM messages, then fault tracing across Ethernet and MPLS domains is enabled, but information loss or distortion may occur during translation
Solution Approach 1:
The system implements feedback mechanisms where the PE router monitors the translation process between LTM and MPLS trace messages. It compares expected responses with actual MPLS trace replies, and adjusts translation parameters accordingly. This feedback loop ensures that critical fault information is preserved during translation, enabling cross-domain fault tracing while minimizing information loss or distortion.
Solution Approach 2:
The fault tracing process is segmented into distinct translation stages: LTM message reception, MPLS trace message generation, MPLS trace reply reception, and LTR message generation. Each stage handles specific information transformations, allowing the system to preserve critical fault location data while adapting to different protocol requirements. This segmentation enables cross-domain versatility while maintaining information accuracy through controlled, staged translations.
Data Source
AI summary
Techniques for providing connectivity fault management (CFM) for a multi-tiered network are described herein. In one embodiment, a link trace message (LTM) is received at a provider edge (PE) router and originated from a first Ethernet node and destined to a second Ethernet node, where the PE router interfaces an Ethernet and a multi-protocol label switching (MPLS) network. In response, the PE router initiates an MPLS trace session, including generating an MPLS trace message based on the LTM message to one or more MPLS nodes along a path between the first and second Ethernet nodes within the MPLS network. Subsequently, in response to one or more MPLS trace reply messages from the MPLS nodes of the MPLS network, the PE router generates a first link trace reply (LTR) message and sends the first LTR message to the first Ethernet node over the Ethernet. Other methods and apparatuses are also described.