MPLS-TP Tunnel Binding via In-Band G-ACH Verification
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Solution Overview
Problem
Conventional MPLS-TP networks face challenges in verifying the association of forward and reverse LSPs between end-points, leading to potential fault conditions such as traffic black holes due to mis-configuration or missing configuration, as each end-point can only verify the association locally.
Innovation Solution
The system employs in-plane exchange of tunnel control messages using the Generic Associated Channel (G-ACH) Advertisement Protocol, enabling dynamic provisioning and teardown of bi-directional associated tunnels by exchanging control plane protocol messages, including an Extended Association Object, between end-point nodes to ensure accurate binding of forward and reverse tunnels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If CLI based end-point association of forward LSP and reverse LSP is used, then local verification at each end-point is simple, but end-to-end association verification fails leading to traffic black holes
Solution Approach 1:
The patent introduces an intermediary verification mechanism where control plane messages are exchanged between end-points through the data plane to confirm association. The forward LSP and reverse LSP associations are verified by passing verification messages through the respective tunnels, ensuring both end-points confirm the association binding before traffic is routed, thereby preventing traffic black holes while maintaining operational simplicity.
2Stability of the object's composition
If static network control signaling protocol is used for tunnel provisioning, then configuration is stable, but dynamic adaptation to network changes is insufficient
Solution Approach 1:
The patent implements dynamic adaptation by enabling control plane protocol messages to be exchanged through the data plane tunnels. This allows the network to dynamically verify and update tunnel associations in response to network changes, while the underlying tunnel configuration remains stable. The system can quickly adapt to failures or reconfigurations by re-verifying associations through the control messages without requiring complete reconfiguration of the static tunnel structures.
3Reliability
If in-band messaging of control plane protocol messages is implemented, then end-to-end association verification is achieved, but data plane overhead increases
Solution Approach 1:
The patent makes the data plane serve a dual function: carrying both user traffic and control plane verification messages. By embedding control plane protocol messages within the data plane tunnel infrastructure, the system achieves end-to-end association verification without requiring separate dedicated control channels. This multi-functional approach distributes the overhead across existing data plane resources rather than creating additional specialized infrastructure, thereby reducing the relative energy cost of verification.
Data Source
AI summary
A source node encapsulates, in a data plane protocol packet, a forward tunnel control message according to a control plane protocol and having an Extended Association Object, and forwards the data plane protocol packet from a source node to a destination node, through a data plane channel. The destination node extracts the Extended Association Object from the data plane protocol packet. Based, at least in part, on the extracted Extended Association Object, the destination node provisions a reverse tunnel from the destination node to the source node, and binds the forward tunnel to the reverse tunnel.