Table of Contents
MAC Control Frame
Introduce the
MAC control frame in Ethernet.
MAC Control Frame Format
Table-1 MAC Control Frame Fileds
| Field | Description |
|---|---|
| Destination Address | 48-bit address of the station(s) for which the frame is intended. It may be an individual or multicast (including broadcast) address. |
| Source Address | 48-bit individual address of the station sending the frame. |
| Length/Type | Fixed to 0x8808. |
| MAC Control Opcode | Indicate the MAC Control function. Some of the functions I have researched are listed here. |
| MAC Control Parameters | MAC Control opcode-specific parameters. The length range of the MAC control parameter field is 0 to 44(1). |
| Reserved | Fill with 0 to achieve 64 bytes ($minFrameSize$). |
MAC Control Functions
Here is just a list of some of the functions I have researched. You can find the full opcodes assignments from 802.3-2022 Annex 31A.
Table-2 MAC Control Functions
| Opcode(Hex) | MAC Control function | Description |
|---|---|---|
00-01 | PAUSE | Requests that the recipient stops transmitting non-control frames for a period of time indicated by the parameters of this function. |
01-01 | PFC | Requests that the recipient stops transmissions in the priorities indicated in the parameters of the function for a period of time also indicated in the parameters. |
Further Reading
- 802.3-2022
- Chapter 31.4 - MAC Control frames
- Annex 31A