3 Ethernet Synchronization Messaging Channel (ESMC)
(Ask a Question)SyncE uses ESMC Protocol Data Unit's (PDU) to transfer the clock source information which allows for clock source traceability to correctly define the timing source to prevent timing loops. ESMC uses the Organization Specific Slow Protocol (OSSP) for transferring and receiving the QL value. ESMC QL values provide the information about the clock quality which helps the node to derive the timing from the most reliable source. The following figure shows the ESMC PDU format.
The following table lists the ESMC QL values.
| Byte Number | Size | Field | Value | |
|---|---|---|---|---|
| 1–6 | 6 bytes | Destination Address | 48'h0180_C200_0002 | |
| 7–12 | 6 bytes | Source Address | 48'h0000_0000_0002 | |
| 13–14 | 2 bytes | Ethernet type | 16'h8809 | |
| 15 | 1 byte | Ethernet sub-type | 8'h0A | |
| 16–18 | 3 bytes | ITU-OUI | 24'h0019A7 | |
| 19–20 | 2 bytes | ITU-T Subtype | 16'h0001 | |
| 21 | 1 byte | Version (bits 7:4) | 4'h1 | |
| Event flag (bit 3) | 1 indicates event PDU, 0 indicates info PDU | |||
| Reserved (bits 2:0) | Reserved | |||
| 22–24 | 3 bytes | Reserved | Reserved | |
| 25–1532 | 4 bytes | TLV_TYPE (1 byte) | 8'h01 | |
| TLV_LENGTH (2 bytes) | 16'h0004 | |||
| SSM CODE (1 byte) | PRC | 8'h02 | ||
| SSU-A | 8'h04 | |||
| SSU-B | 8'h08 | |||
| SEC | 8'h0B | |||
| DNU | 8'h0F | |||
| — | 32–1486 bytes | Future Enhancement | — | |
| Last 4 | 4 bytes | FCS | Core10GMAC computes the FCS and appends to the Frame before transmitting out. | |
- Destination Address (DA): This is the IEEE®-defined slow protocol multicast address.
- Source Address (SA): The source address is the MAC address associated with the port through which the ESMC PDU is transmitted.
- Slow Protocol Ether type: ESMC PDU’s must be type encoded and carry the slow protocol type field value.
- Slow Protocol subtype: Assigned by the IEEE and fixed with a value of 0x0A.
- ITU OUI: Organizational unique identifier assigned by the IEEE registration authority.
- ITU subtype: Assigned by ITU-T. The value of 00–01 applies to all usage defined in this recommendation.
- Version: The 4-bit field indicates the version of the ITU-T OSSP frame format. This field contains the value 0x1 to claim compliance with version 1 of this protocol.
- Event flag: This bit distinguishes the critical, time-sensitive behavior of the ESMC event PDU from the ESMC Information PDU. A value of 1 indicates an event PDU and a value of 0 indicates an information PDU.
- Data and Padding: The minimum frame size of 64 bytes and the maximum size for the ESMC PDU is 128 bytes.
- FCS: Four-byte frame check sequence as defined in clause 4 of IEEE 802.3.
The PolarFire FPGA 10G SyncE solution is compliant with the IEEE 802.3ae standard, which supports data transfer rates of up to 10.3125 Gbps. Advantages offered by using PolarFire FPGAs for building 10G Ethernet solutions include the use of low-power transceivers, low-power FPGA fabric, and in-built SyncE-compliant jitter attenuation.
The 10G Ethernet solution is implemented using the Core10GMAC soft IP Media Access Control (MAC) core, which can be configured either in 10GBASE-KR mode or 10GBASE-R mode. This demo design includes the following design, which can be used as reference designs for building a 10GBASE-R.
Ethernet loopback application: A 10GBASE-R Ethernet 64-bit loopback design that can be run on the PolarFire Evaluation Board using Paragon-X Network Tester.