[Type text]

7. Application

6. Presentation

5. Session

4. Transport

3. Network

2. Data Link

1. Physical PDU: bits

Notes: different media (copper, fiber, wireless)

advantages/disadvantages of each kind. When to use ST/Cross?

And how to tell the difference between them.

Protocols:

TCP UDP

OSI Reference

Model

• This layer serves as the source and destination of

communications across data networks.

• Directly accessing the underlying processes that

manage and deliver communication to the human

network.

• Enabling users to interact with the data network in a

way that is meaningful and effective.

Dividing data received from an application into segments

Adding a header to identify and manage each segment

Using the header information to reassemble the segments

back into application data

Passing the assembled data to the correct application

Enabling data to be directed to the correct application

running on end devices using port numbers.

Carrying data from one host to another regardless of

the type of data.

Layer 3 IP routing does not guarantee reliable

delivery or establish a connection before data is

transmitted. This connectionless and unreliable

communication is fast and flexible, but upper layers

must provide mechanisms to guarantee delivery of

data if it is needed.

Preparing Network layer packets for

placement onto the physical media that

transports data.

Encoding the bits for transmission and decoding them at the

destination.

Describing the physical, electrical, and mechanical

characteristics of the physical media and connectors that

interconnect network devices.

Various media and Physical layer protocols have different

data-carrying capacities. Raw data bandwidth is the theoretical

upper limit of a bit transmission. Throughput and goodput are

different measures of observed data transfer over a specific

period of time.

PDU: Data Stream

Protocols:

DNS: used to resolve Internet names to IP addresses.

HTTP: used to transfer files that make up the

Web pages of the World Wide Web.

SMTP: used for the transfer of mail messages

and attachments (MUA MTA, MTA MTA)

POP: mail delivery protocols. They deliver e-

mail from the e-mail server (MDA) to the client

(MUA)

Telnet: terminal emulation protocol used to

provide remote access to servers and

networking devices.

PDU: Segment

PDU: Packet Protocols: IPv4, IPv6

Notes:

L3 uses logical addresses to

identify and route traffic from one

network to another.

Network/subnet address.

Broadcast address. Host address.

Subnet mask.

Public vs. private addresses

Default Gateway

Purpose of the routing table

PDU: Frame

Notes:

L2 uses physical addresses to identify nodes and deliver

frames in the local network/segment.

Ethernet is the most widely used LAN technology.

CSMA/CD, CSMA/CA, Token passing