How to find the OUI in a World Wide Node Name (WWNN) or World Wide Port Name (WWPN)
Each Fibre Channel node or networking device will have one and only one WWNN that uniquely identifies it. Each of these devices will have at least one and frequently very large numbers of ports (in the case of a switch for instance). Each of these ports is uniquely identifiable by its WWPN which is created based on the WWNN, so that any device will have one WWNN but could have many related WWPNs. The Fibre Channel naming format can take one of several forms. In general, the first nibble (4bits or 1/2 byte identifies the type of WWN. The second section depends on the type of WWN:
1. IEEE Name (NAA-1) The first nibble is a 1. The the next nibble and byte will equal 0:00. For example, 10:00:XX.XX.XX.VV.VV.VV, where the X represents OUI and the V indicates vendor assigned bytes).
IEEE name (NAA-1) – 10:00:00:00:c9:55:23:6b >00:00:c9<<<<<< OUI
2. IEEE Extended name (NAA-2) – The first nibble is a 2. The next 12 bits (1 nibble + 1 Byte) is vendor assigned, and is frequently used to identify port number on a multiport node. For example, 2P:PP:XX:XX:XX:VV:VV:VV (P is vendor assigned possibly a port ID, X is OUI, and V is vendor assigned)
IEEE Extended name (NAA-2) – 20:00:00:e0:8b:05:05:04 >00:e0:8b<<<<<<< OUI
3. IEEE Registered name (NAA-3) – The first nibble is a 2. The next three bytes are the OUI with the next 4 1/2 bytes are vendor assigned, frequently being the serial number with the last three nibbles being used for port identification. For example, 5X:XX:XX:XV:VV:VV:Vv:vv (where X is OUI, and V is vendor assigned might be serial number and v port ID)
IEEE Registered name (NAA-3) – 50:0a:09:81:87:39:45:3b >0:0a:09:8<<<<<<<<<<<OUI