almanach network MAC
Ethernet numbers include a 48-bit media access control (MAC) address assigned to each Ethernet interface, and the 16-bit value used in the Type field of the Ethernet frame.
Each Ethernet interface is assigned a unique MAC address at the time of manufacture. The first 24 bits of the MAC address consist of an Organizationally Unique Identifier (OUI) assigned to a vendor by the IEEE (which is why they are also called vendor codes). The Ethernet vendor combines their 24-bit OUI with a unique 24-bit value that they generate to create a unique 48-bit address for each Ethernet interface they build.
An Ethernet Type code is a 16-bit number carried in the Type field of the Ethernet frame. This number is used to identify the type of high-level network protocol packet that is being carried in the data field of the Ethernet frame.
OUI (vendor) codes and Type codes can help identify and track down machines and protocols in use on the network. For example, the OUI codes can help identify the vendor of a given Ethernet card that may be sending incorrect traffic. Knowing the vendor can often help you find out which machine on your network may be the one causing problems.
- IEEE Organizationally Unique Identifier (OUI) page.
This IEEE page provides search access to their list of OUIs and provides download access to the entire IEEE OUI list. Note that the IEEE list of OUIs is not complete, since vendors can request not to be publically listed (GO TO identify by MAC address section)
- IEEE Ethernet type listing
- IEEE type field
This IEEE page provides a public list of Type field assignments and the organizations which requested them. This list only identifies the organizations who have requested a Type field for use in their work on protocol development. Michael Patton's list should be consulted for the actual Type identifier used for a given protocol.
- Michael Patton's List of OUIs and other Ethernet numbers.
Michael Patton's list of OUIs was created by volunteers who sniffed packets on their networks and recorded the OUIs. This list may be more complete than the IEEE list for older OUIs, but since it does not appear to be actively maintained it is probably out of date.
- Glenn Smith's List of OUIs.
A useful list of Ethernet OUIs that provides Web-based searching on OUI and vendor name.
- Protocol Numbers and Assignment Services.
Maintained by the Internet Assigned Numbers Authority (IANA). Includes assigned multicast addresses.