---
name: "mii"
section: "4"
platform: "openbsd"
package: "man"
version: "8.0-current-20261101"
release: "OpenBSD 8.0-current (2026-11-01)"
platforms: ["openbsd"]
url: "https://new.carta.tech/mii"
---

# mii(4)

IEEE 802.3 Media Independent Interface

## NAME

**mii** – IEEE 802.3 Media Independent Interface

## SYNOPSIS

**acphy\* at mii?** **amphy\* at mii?** **atphy\* at mii?** **bmtphy\* at mii?** **brgphy\* at mii?** **ciphy\* at mii?** **dcphy\* at mii?** **eephy\* at mii?** **etphy\* at mii?** **exphy\* at mii?** **gentbi\* at mii?** **icsphy\* at mii?** **ipgphy\* at mii?** **inphy\* at mii?** **iophy\* at mii?** **jmphy\* at mii?** **luphy\* at mii?** **lxtphy\* at mii?** **mtdphy\* at mii?** **nsgphy\* at mii?** **nsphy\* at mii?** **nsphyter\* at mii?** **qsphy\* at mii?** **rdcphy\* at mii?** **rgephy\* at mii?** **rlphy\* at mii?** **sqphy\* at mii?** **tlphy\* at mii?** **tqphy\* at mii?** **txphy\* at mii?** **ukphy\* at mii?** **urlphy\* at mii?** **xmphy\* at mii?** **ytphy\* at mii?**

## DESCRIPTION

Media Independent Interface is an IEEE standard serial bus for connecting MACs (network controllers) to PHYs (physical media interfaces). The **mii** layer allows network device drivers to share support code for various PHY models, and allows unused support for PHYs which are not present in a system to be removed from the kernel.

Network device drivers which use the **mii** layer carry the “mii” autoconfiguration attribute. This allows kernel configuration files to simply specify PHYs as described above in SYNOPSIS.

The following is an example of the messages displayed when a network interface with an attached PHY is detected by the kernel:

```
hme0 at sbus0 slot 1 offset 0x8c00000 pri 7: address 08:00:20:22:86:b8 rev 34
nsphy0 at hme0 phy 1: DP83840 10/100 PHY, rev. 1
```

Supported media types for the PHY can be displayed or set using the [ifconfig(8)](/ifconfig/8.md) **media** keyword.

## SEE ALSO

[ifmedia(4)](/ifmedia/4.md), [intro(4)](/intro/4.md), [netintro(4)](/netintro/4.md), [ifconfig(8)](/ifconfig/8.md)