User`s guide

Signamax 065-7931 16-Port 10/100/1000BaseT/TX WebSmart Switch
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3-2. Media Access Control (MAC)
MAC Addressing
Because a LAN is composed of many nodes, for the data exchanged among
these nodes, each node must have its own unique address to identify who should
send the data or should receive the data. In the OSI model, each layer provides its
own means to identify the unique address in some form; for example, an IP address
in the network layer.
The MAC belongs to the Data Link Layer (Layer 2); the address is defined to
be a 48-bit long and locally unique address. Since this type of address is applied
only to the Ethernet LAN media access control (MAC), they are referred to as MAC
addresses.
The first three bytes are Organizational Unique Identifier (OUI) code
assigned by IEEE. The last three bytes are the serial number assigned by the
vendor of the network device. All six of these bytes are stored in a non-volatile
memory in the device. Their format is as shown in the following table and normally
written in the form as aa-bb-cc-dd-ee-ff, a sequence of 12 hexadecimal digits
separated by hyphens, in which the aa-bb-cc is the OUI code and the dd-ee-ff is the
serial number assigned by the manufacturer.
Fig. 3-2 SAP Format