User:Itpastorn/dko/ccna1-3.1-2

Networking Fundamentals

Overview CCNA 1 - Module 2 (3.1)

• Explain the importance of bandwidth
• Identify bps, kbps, Mbps, and Gbps
• Explain the difference between bandwidth and throughput
• Calculate data transfer rates
• Why layered models
• The development of the OSI model
• The advantages of a layered approach
• The seven layers of the OSI model
• The four layers of the TCP/IP model
• Similarities and differences between the two models
• Outline the history of networking (briefly)
• Devices used in networking
• The role of protocols in networking
• Define LAN, WAN, MAN, and SAN (Lars Gunther adds: VLAN, WLAN and PAN)
• VPN
• Intranets and extranets

Networking Terminology

Data Networks

• Stand alone computer
• Sneakernet
• LAN (but only small ones with no connection between them)
• Inter-net-working - connecting LANs

Network History

Ethernet History

Networking devices

• End user devices
  • Computers
  • Printers
  • Scannerss
  • Etc
• Network devices
  • Repeater
  • Hub
  • Bridge
  • (Workroup) Switch
  • Router
  • Network cloud
  • Etc.

Terminology

• Node (networking)
• Host (network)
• Data Terminal Equipment
• Data Communications Equipment - The Cisco definition: "provides clocking"

Network topology

Physical vz. logical

• Bus topology
• Ring topology
• Star topology
• Extended star topology
• Hierarchical topology
• Mesh topology

Network protocolss

• 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

LANs

Common technologies:

• Ethernet
• Token ring - once upon a time...
• FDDI - once upon a time...

WANs

Common technologies:

• Modem
• ISDN
• DSL
• Frame Relay
• T-carrier and E-carrier, e.g. T1, E1, T3 and E3
• SONET
• ATM
• MPLS

MAN

"two or more LANs in a common geographic area"

SAN

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

Virtual private network (VPN)

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

Benefits of VPN

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

Technologies

• Dialup
• Tunneling protocols
• Cryptography

Bandwidth

• A Guide to Bandwidth and Throughput
• List of device bandwidths

Importance of Bandwith

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

The desktop

Two analogies:

• Traffic
• Water

Measurement (of bandwith)

• bps
• kbps
• Mbps
• Gbps
• Tbps

Limitations

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

Throughput

"Actual measured bandwith"

• iperf

Data transfer calculation

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

Digital vz analog 

Analog bandwith = what frequencies are occupied

Networking Models

An Introduction To The Tcp/Ip And OSI Model

Using layers to analyze problems in a flow of materials´

• Source
• Destination
• Packet
• Medium

OSI model

Evolved from:

• DECnet
• SNA
• TCP/IP model
• Etc.

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

OSI layers

• "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!

• List of network protocols
• Upper layer protocol
• Lower layer protocol

Peer-to-peer communications

• Protocol data unit (PDU)

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.

TCP/IP model

In detail in Module 9

Detailed encapsulation process

How Encapsulation Works Within the TCP/IP Model

• Encapsulation

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)

Additional terminology

• Number of hosts involved
  • Unicast
  • Multicast (IP and MAC)
  • Broadcast (IP and MAC)
• Synchronization
  • Synchronous  See also Synchronous in the ATM Dictionary
  • Asynchronous communication See also Asynchronous in the ATM Dictionary
  • Isochronous . See also Isochronous in the ATM Dictionary
• Parallelism
  • Parallel communication
  • Serial communication
• Switching methods
  • Packet switching
  • Circuit switching
  • Cell relay
• Connection aspects
  • Connectionless (E.g. Ethernet, IP, UDP)
  • Connection oriented (E.g. X.25, Frame relay, Asynchronous Transfer Mode (ATM), Multiprotocol Label Switching (MPLS), and TCP)

Standardization organizations

• Institute of Electrical and Electronics Engineers (IEEE)
• American National Standards Institute ANSI
• Telecommunications Industry Association (TIA)
• Electronic Industries Alliance (EIA)
• International Telecommunications Union (ITU), formerly known as the Comité Consultatif International Téléphonique et Télégraphique (CCITT).
• Internet Assigned Numbers Authority (IANA)
• World Wide Web Consortium (W3C)
• Ecma International (ECMA)
• International Organization for Standardization (ISO)
• Unicode Consortium
• Post- och telestyrelsen (PTS)
• Etc.

Additional resources (besides Wikipedia)

• CCNA 1 Module 2 Exam Solutions at Learn Networking
• IBM Redbook on SAN

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