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Networking Fundamentals

Overview CCNA 1 - Module 2 (3.1)

Networking Terminology

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Data Networks

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Network History

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Ethernet History

Networking devices

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Terminology

Physical vz. logical

  • Protocol suites = collections of protocols.
  • Enables network communication between hosts.
  • A formal description of a set of rules and conventions
  • Protocols specify
    • The format of the data
    • The timing
    • The sequencing
    • Error control

Common technologies:

Common technologies:

"two or more LANs in a common geographic area"

A storage area network (SAN) is an architecture to attach remote computer storage devices (such as disk arrays, tape libraries and optical jukeboxes) to servers in such a way that, to the operating system, the devices appear as locally attached.

  • Dedicated
  • High-performance
  • Scalability
  • Availability

A virtual private network (VPN) is a communications network tunneled through another network, and dedicated for a specific network.

Benefits of VPN

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  • Same policies and security as a private network
  • Cost effective

Technologies

Bandwidth

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Importance of Bandwith

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  • Finite
  • Not free
  • In demand!
  • Critical (together with latency)

The desktop

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Two analogies:

  • Traffic
  • Water

Measurement (of bandwith)

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  • bps
  • kbps
  • Mbps
  • Gbps
  • Tbps

Limitations

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"Actual bandwidth --- is determined by a combination of the physical media and the technologies chosen"

Throughput

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"Actual measured bandwith"

Data transfer calculation

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T=S/BW (and then add some for the overhead caused by incapsulation)

Analog bandwith = what frequencies are occupied

Networking Models

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An Introduction To The Tcp/Ip And OSI Model

Using layers to analyze problems in a flow of materials´

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  • Source
  • Destination
  • Packet
  • Medium

Using layers to describe data communication

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Evolved from:

Released in 1984. "It is considered the best tool available for teaching people about sending and receiving data on a network."

OSI layers

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  • "Please Do Not Teach Such Petty Acronyms" (1-7)
  • "Please Do Not Throw sausage Pizza Away" (1-7)
  • "All People Seem To Need Data Processing" (7-1)

Test yourself: Briefly describe each layer!

Peer-to-peer communications

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The layer of communication on the source computer communicates with its peer layer on the destination computer, using the layer-specific PDU. Every layer provides a service to the layer above.

In detail in Module 9

Detailed encapsulation process

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How Encapsulation Works Within the TCP/IP Model

  1. Build the data
  2. Package the data for end-to-end transport (TCP or UDP segment)
  3. Add the network IP header (IP packet)
  4. Add the data link layer header and trailer (Ethernet Frame)
  5. Convert to bits for transmission (physical signals)

Extra topics (in addition to CCNA)

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Additional terminology

Standardization organizations

Additional resources (besides Wikipedia)

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