Structure and Use of Data Exchange Standards
OSI 7 Layer Model: Layers 4, 3, 2 and 1
11
Layer Application/Example
4. Transport. Ensures that messages
are delivered error-free, in sequence and
with no losses and duplication
Transmission Control Protocol -
TCP (host to host, flow control)
3. Network. Controls the operations of
the subnet, deciding the physical path
the data takes
Packets (“letter,” contains IP
address)
2. Data Link. Provides error-free
transfer of data frames from one node to
another over the Physical layer
Frames (“envelopes,” contains
MAC address)
1. Physical. Concerned with
transmission and reception of raw bit
stream over physical medium
Physical structure (cables, hubs,
etc.)