In effect, its role is to ensure transmission free of errors.
2 The IEEE 802.3 defines Ethernet in the LAN (and since 2005, also in the MAN)
3 The Open Systems Initiative (OSI) defined by the International Standards Organization as the standard
7498-1, in 1984. This is the primary architectural model employed in networking.
4 Binary digits (i.e., Os and 1s using which data is communicated)
5 It could be over a non-???physical??™, i.e., a wireless medium as well (such as is the case with Wireless Fidelity
or WiFi).
6 Ethernet implementations typically use baseband transmission not broadband transmissions.
7 As opposed to a hierarchical addressing space (e.g., used in regular mailing addresses, where there are
many subgroups (addresses) based on an element, say, City Name; and from the networking realm, IP
address assignment is another example of hierarchical addressing.
Ethernet: From LAN to the WAN 5
In the IEEE 802.3 standard, the Data-Link Layer (DLL) of the OSI model is essentially
split into two sublayers: Media Access Control (MAC) and the Logical-link control
(which resides on top of the MAC sublayer).
Media Access Control (MAC) sublayer This sublayer defines medium-independent
capabilities that are built upon the Physical layer and encompasses two main functions:
?– Data encapsulation Includes assembling and right-sizing8, if necessary, the
Ethernet frame prior to transmitting and also detecting any errors at receipt of an
Ethernet frame.
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