H31-341_V2.5 · Question #770
If the tunnel to which the PW belongs is configured with tunnel APS, the PW cannot be configured with PW APS.
The correct answer is B. False. B (False) is correct because Tunnel APS and PW APS operate at different network layers and can coexist without conflict. Tunnel APS protects the transport tunnel (LSP level), while PW APS protects the pseudowire service layer - configuring both simultaneously provides layered…
Question
If the tunnel to which the PW belongs is configured with tunnel APS, the PW cannot be configured with PW APS.
Options
- ATrue
- BFalse
How the community answered
(26 responses)- A27% (7)
- B73% (19)
Explanation
B (False) is correct because Tunnel APS and PW APS operate at different network layers and can coexist without conflict. Tunnel APS protects the transport tunnel (LSP level), while PW APS protects the pseudowire service layer - configuring both simultaneously provides layered, dual-level redundancy. These two protection mechanisms are complementary, not mutually exclusive.
Why A is wrong: The statement is a false restriction. No standard or common vendor implementation (e.g., Huawei) prevents PW APS from being configured simply because the underlying tunnel already has APS. Assuming they conflict confuses independence with incompatibility.
Memory tip: Think of it like seat belts and airbags - both protect you in a car, at different layers of protection, and having one does not prevent you from having the other. Similarly, tunnel APS (the "airbag") and PW APS (the "seat belt") can both be active together.
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