Ethernet Driver: NE2000

Contributors:

Douglas Armstrong: Shared code base.

The main driver core is finished! It has been (sorta) tested and appears to be able to both send and receive packets off the Ethernet. So far it seems stable. It's ready and now available under the shared code base, talk to me for details.

The documentation has been completed and is online:

Documentation for the NE2000 driver core.

For the upper layers in the protocol stack it is important to know the format of the Ethernet frame header:

Destination Address	6 bytes	Hardware address of target card
Source Address	6 bytes	Hardware address of originating card
Protocol Type / Frame Length	2 bytes	Multiplexed data, see below.

The Ethernet supports two kinds of frames to be sent over the wire, Ethernet II and 802.3. The Ethernet II frame stores the protocol type in the header. Some common entries are IP, ARP, Loopback, etc... The 802.3 style stores the length of the packet in the header in place of the protocol type. This is possible because all the protocol types are enumerated with numbers greater than 1500, which is the upper bound on an Ethernet frame length. This allows the two types it coexist happily and for them to both use the field differently. We did some tracing, and it appears that the Macs were using multicast address with 802.3 frames.