VLAN

If you are looking for a software implementation of the 802.1Q VLAN protocol for Linux, VLAN is a great option to consider. It allows you to create Virtual LANs on a single ethernet cable, which makes it possible to separate LANs efficiently. One of the best things about VLAN is its ability to support up to 4094 vlan interfaces per ethernet device.

Here are some key features of VLAN:

- Implements 802.1Q VLAN spec.
- Implements support for a non-standard (as far as I know) MAC-based VLAN functionality.
- Can support up to 4094 VLANs per ethernet interface.
- Scales well in critical paths: O(n), where n is the number of PHYSICAL ethernet interfaces, and that is only on ingress. O(1) in every other critical path, as far as I know.
- Supports MULTICAST
- Can change MAC address of VLAN.
- Multiple naming conventions supported, and adjustable at runtime.
- Optional header-reordering, to make the VLAN interface look JUST LIKE an Ethernet interface. This fixes some problems with DHCPd and anything else that uses a SOCK_PACKET socket. Default setting is off, which works for every other protocol I know about, and is slightly faster.

If you are wondering what's new in the latest release, it fixes return error codes in vconfig. Overall, VLAN is a reliable software that provides excellent VLAN functionality, making it a must-have for anyone looking to create Virtual LANs on their Linux device.