# Physical layer mapping specification
This specification describes how the transport layer is mapped onto various physical layers.
Z-Mesh frames can be sent directly on the physical layer or it can be tunneled in a layer 3 protocol like UDP/IP. Z-Mesh is a physical layer independent protocol, so it can run on anything that support an MTU-size greater that 64 bytes.
# 2.4 GHz
Frame format:
| Preamble 3 bytes | Sync word 2 bytes | Len 1 byte | Z-Mesh frame N bytes |
|---|
The physical layer properties are as follows:
| Property | value |
|---|---|
| Frequency | 2401 - 2483 MHz |
| Bits/sec | 1 Mbps |
| Encoding | 2-FSK with gaussian filter value of 0.5 |
| Preamble | 3 bytes 0xAA, 0xAA, 0xAA |
| Sync word | 2 bytes 0xDD, 0xDD |
# Sub-GHz
Frame format:
| Preamble 3 bytes | Sync word 2 bytes | Len 1 byte | Z-Mesh frame N bytes |
|---|
The physical layer properties are as follows:
| Property | value |
|---|---|
| Frequency | 433MHz, 868.0 - 868.6 MHz, 915MHz |
| Bits/sec | 50 Kbps |
| Encoding | 2-FSK with gaussian filter value of 0.5 |
| Preamble | 3 bytes 0xAA, 0xAA, 0xAA |
| Sync word | 2 bytes 0xDD, 0xDD |
# 802.11 (ethernet)
TBD.
# 802.11ah (Halo)
TBD.
# 802.15.4
TBD.
# UDP
Frame format:
| UDP header | Z-Mesh frame |
|---|
The Z-Mesh frame is sent directly using UDP.