Explains how MACsec state reflections allow interface line protocols to mirror the state of the MACsec session, enabling rapid failure detection and preventing silent traffic loss.
MACsec state reflection on line protocol is a network feature that:
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synchronizes the interface line protocol state with the MACsec Key Agreement (MKA) session state,
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transitions the line protocol to Down when the MACsec session is not secured and the security policy is set to must-secure, thereby preventing upper-layer protocols from using the interface and avoiding traffic blackholing, and
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enables faster failure detection by upper-layer protocols such as LACP and BGP, allowing rapid convergence and traffic rerouting.
In long-haul or complex deployments, connectivity failures can occur at intermediate devices without impacting the local physical interface state. As a result, the interface may remain Up while the MKA session times out and goes down. More generally, the MACsec session can become unsecured due to intermediate network failures, configuration issues, or other connectivity issues.
By reflecting MACsec session state in line protocol state, the interface line protocol is transitioned to Down when the session is not secured, allowing upper-layer protocols to immediately detect failure and reroute traffic. When the session becomes secured, the line protocol is restored to Up. For bundle member interfaces, this ensures the interface is no longer active for forwarding when the line protocol is Down and is restored to active membership after the line protocol returns to Up, subject to bundle mode and convergence.
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Feature Name |
Release Information |
Feature Description |
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MACsec state reflection on line protocol |
Release 26.2.1 |
Introduced in this release on: Fixed Systems (8200 [ASIC: Q100, Q200, P100], 8700 [ASIC: P100, K100], 8010 [ASIC: A100]); Centralized Systems (8600 [ASIC:Q200]) ; Modular Systems (8800 [LC ASIC: Q100, Q200, P100]) MACsec State Reflection on line protocol synchronizes the interface line protocol state with the MACsec session state. When the session is not secured and the security policy is set to must-secure, the interface is brought Down to prevent traffic blackholing. When the session is secured, the interface is restored to Up. This enables faster failure detection and traffic rerouting by upper-layer protocols such as LACP and BGP. Previously, MACsec session failures did not affect the interface's line protocol status, often resulting in silent traffic drops and delayed network convergence. CLI: enable fault-detection |