Abstract
A timing-distribution technique is described for telecom packet networks that use IEEE 1588 PTP (e.g., ITU-T G.8275.1 full timing support) for phase/time and SyncE for frequency, where SyncE master selection is primarily based on Quality Level (QL) conveyed via ESMC. In networks that simultaneously deploy hop-by-hop MACsec and end-to-end (tunneled) MACsec domains, operational visibility of the true SyncE “trail” can become ambiguous, leading downstream nodes to select a locally acceptable but performance-inferior frequency reference that traverses additional unsecured/opaque intermediate hops and accumulates more jitter/wander. To bias selection toward more deterministic, regenerated hop-by-hop SyncE paths, the disclosure proposes encoding a MACsec-topology indicator in reserved bytes of the ESMC PDU (e.g., octets 23–24), such as inserting the MKA/EAPOL EtherType 0x888E to mark hop-by-hop MACsec delivery. A receiving clock (e.g., an enhanced equipment clock) applies standard QL/priority rules and additionally uses the embedded indicator as a preference/tie-breaker to choose the hop-by-hop path, reducing manual operator intervention and improving frequency stability and traceability in secured multi-path timing topologies.
Creative Commons License
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Recommended Citation
Anonymous, "Optimal SyncE Source Selection in Networks Employing MACsec Security", Technical Disclosure Commons, ()
https://www.tdcommons.org/dpubs_series/9052