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SyncE also has a status messaging channel (similar to the Synchronisation Status Messaging, SSM, defined for SDH equipment). This is called the Ethernet Synchronisation Message Channel (ESMC), defined in G.8264, and is backwards-compatible with SSM, allowing for inter-operation with existing SDH synchronisation chains. These messages are only used for the “control plane” of SyncE, the actual frequency reference is distributed through the physical clocking of the bits on the SyncE interfaces.
| Concepts / Overview | CX3002 | Jitter and Wander in SyncE: Testing Jitter and Wander to ITU-T Standards |
|---|---|---|
| CX8010 | The importance of measuring wander on high speed interfaces | |
| General Information | G.8260 | Definitions and Terminology for Synchronisation in Packet Networks |
| Clock Specifications | G.811 | Primary Reference Clock (PRC) Specification |
| G.812 | Synchronisation Supply Unit (SSU) Specification | |
| G.8262 | Ethernet Equipment Clock (EEC) Specification | |
| Network Specifications | G.8261 | SyncE Network Limits (clause 9.2.1) |
| Protocol Specifications | G.8264 | Ethernet Synchronisation Messaging Channel (ESMC) (clause 11) |
| Test Guide | CX5018 | Sentinel Field Test Plan for Frequency Synchronisation using PTP |
| CX5001 | G.8262 SyncE conformance testing: Proving SyncE compliance to ITU-T G.8262 using Paragon-X | |
| CX5026 | Testing EECs to ITU-T G.8262 using Paragon-100G |
Method 1b: Precision Time Protocol (PTP)
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The GM encodes the frequency into packet streams using PTP, and sends it over the packet network to the PTP Slave clock. The packet network consists of ordinary switches and/or routers, with no special adaptation for handling PTP messages. The slave clock is responsible for converting the packet stream back into a frequency for transmission over a physical layer clock to the basestation.
| Concepts / Overview | ||
|---|---|---|
| General Information | G.8260 | Definitions and Terminology for Synchronisation in Packet Networks |
| G.8265 | Architecture and requirements for packet-based frequency delivery | |
| Clock Specifications | G.811 | Primary Reference Clock (PRC) Specification |
| G.8266 | PTP Frequency Grandmaster Clock Specification (Packet Equipment Clock – Master, PEC-M) | |
| G.8263 | PTP Frequency Slave Clock Specification (Packet Equipment Clock – Slave – Frequency, PEC-S-F) | |
| Network Specifications | G.8261.1 | PTP Network Limits |
| Protocol Specifications | G.8265.1 | PTP Telecom Profile for Frequency |
| IEEE1588 | Precision Time Protocol | |
| Test Guide | CX5018 | Sentinel Field Test Plan for Frequency Synchronisation using PTP |
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