Jaringan Komputer Dasar

Jaringan Komputer DasarData Link Layer (1)

Aurelio Rahmadian

ObjektifData Link LayerTeknik Media Access Control

Data Link Layer

Data Link LayerThe 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 detectionAs with each of the OSI layers, there are terms

specific to this layer: o Frame - The Data Link layer PDUo Node - The Layer 2 notation for network devices connected to a common

mediumo Media/medium (physical) - The physical means for the transfer of information

between two nodeso Network (physical) - Two or more nodes connected to a common medium

Data Link Layer

Data Link Layer

Data Link LayerData 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 ControlMedia 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 ControlMedia access control protocols

for non-shared 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