Transforming Process Safety Management: Challenges, Benefits, and Transition ...
Issues in Data Link Layer
2. Issues in Data Link Layer
• The main job of the data link layer is to make the
communication on the physical link reliable &
efficient.
Issues,
– Provide interface to the network layer services.
– Framing
– Flow Control
– Error Control
– Synchronization
– Link Configuration Control.
3. Issues in Data Link Layer
Services provided to Network layer
Virtual Communication
Actual Comunication
4. Types of services provided to the Network Layer,
Unacknowledged Connectionless service
Acknowledged Connectionless service
Acknowledged Connection oriented service
Framing
• Translation of physical layer’s raw bits into a larger
aggregate (or) discrete units called frames.
• Here beginning and end of the data are marked to
recognize the frame & used in synchronization.
Issues in Data Link Layer
5. Synchronization
• Receiver must know, when the data begins & when it
ends and also receiver should be able to distinguish
between each bit in the frame of data.
Flow Control
• Refers to the mechanisms that make sure that the
sending station cannot overwhelm the receiving
station.
• Preventing the buffer overflow.
Eg., Sliding Window.
Issues in Data Link Layer
6. Error Control
• All transmission media have potential for
introduction of errors.
• Error control mechanisms can detect as well as
correct errors.
Link Configuration Control
• Link Topology
Physical arrangement of the connection between the
devices.
• Link Duplexity
Simplex – only one device can transmit to other. (ie.,
one direction transmit)
Issues in Data Link Layer
7. half duplex – Both device can transmit to each other, but
not simultaneously.
full duplex – Both device can transmit simultaneously.
Issues in Data Link Layer