Jaringan Komputer Dasar
Data Link Layer (1)
Aurelio Rahmadian
Objektif
Data Link Layer
 Teknik Media Access Control

Data Link Layer
Data Link Layer
The Data Link layer provides a means for
exchanging data over a common local media.
 The Data Link layer performs two basic services:

o Allows the upper layers to access the media using techniques such as framing
o Controls how data is placed onto the media and is received from the media
using techniques such as media access control and error detection

As with each of the OSI layers, there are terms
specific to this layer:
o Frame - The Data Link layer PDU
o Node - The Layer 2 notation for network devices connected to a common
medium
o Media/medium (physical) - The physical means for the transfer of information
between two nodes
o Network (physical) - Two or more nodes connected to a common medium
Data Link Layer
Data Link Layer
Data Link Layer

Data Link layer protocols require control
information to enable the protocols to
function. Control information may tell:
◦ Which nodes are in communication with each
other
◦ When communication between individual
nodes begins and when it ends
◦ Which errors occurred while the nodes
communicated
◦ Which nodes will communicate next
Data Link Layer
Data Link Layer
Data Link Layer
Data Link Layer
Teknik Media Access Control
Media access control is the equivalent of traffic
rules that regulate the entrance of motor vehicles
onto a roadway. The absence of any media access
control would be the equivalent of vehicles
ignoring all other traffic and entering the road
without regard to the other vehicles.
 The method of media access control used
depends on:

◦ Media sharing - If and how the nodes share the media
◦ Topology - How the connection between the nodes
appears to the Data Link layer
Teknik Media Access Control
Teknik Media Access Control
Teknik Media Access Control
Teknik Media Access Control

Media access control protocols for nonshared media require little or no control
before placing frames onto the media.
These protocols have simpler rules and
procedures for media access control. Such
is the case for point-to-point topologies.
Teknik Media Access Control