Pertemuan 1 WAN

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Pertemuan 1 WAN
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Discussion Topics

• Introduction to WANs
• Introduction to routers in a WAN
• Router LANs and WANs
• Role of routers in a WAN
• Academy approach to hands-on labs

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Introduction to WANs

• A WAN is a data communications network that spans
  a large geographic area such as a state,
  province, or country.

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WAN Devices

• The following devices are used in WANs  
• Routers offer many services, including
  internetworking and WAN interface ports.
• Modems include interface voice-grade services,
  channel service units/digital service units
  (CSU/DSUs) that interface T1/E1 services, and
  Terminal Adapters/Network Termination 1 (TA/NT1s)
  that interface Integrated Services Digital
  Network (ISDN) services.
• Communication servers concentrate dial in and
  dial out user communication.

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WAN Services
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Data Link Encapsulations

• WAN data link protocols describe how frames are
  carried between systems on a single data link.
  They include protocols designed to operate over
  dedicated point-to-point, multipoint, and
  multi-access switched services such as Frame
  Relay. WAN standards are defined and managed by a
  number of recognized authorities, including the
  following agencies
• International Telecommunication
  Union-Telecommunication Standardization Sector
  (ITU-T), formerly the Consultative Committee for
  International Telegraph and Telephone (CCITT)
• International Organization for Standardization
  (ISO)
• Internet Engineering Task Force (IETF)
• Electronic Industries Association (EIA)

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Routers Connected by WAN Technologies
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Internal Configuration Components
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RAM

• RAM has the following characteristics and
  functions
• Stores routing tables
• Holds ARP cache
• Holds fast-switching cache
• Performs packet buffering as shared RAM
• Maintains packet-hold queues
• Provides temporary memory for the configuration
  file of a router while the router is powered on
• Loses content when a router is powered down or
  restarted

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NVRAM , FLASH MEMORY

• NVRAM has the following characteristics and
  functions
• Provides storage for the startup configuration
  file
• Retains content when a router is powered down or
  restarted

• Flash memory has the following characteristics
  and functions
• Holds the IOS image
• Allows software to be updated without removing
  and replacing chips on the processor
• Retains content when a router is powered down or
  restarted
• Can store multiple versions of IOS software
• Is a type of electrically erasable programmable
  read-only memory (EEPROM)

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ROM , INTERFACE

• ROM has the following characteristics and
  functions
• Maintains instructions for power-on self test
  (POST) diagnostics
• Stores bootstrap program and basic operating
  system software
• Requires replacing pluggable chips on the
  motherboard for software upgrades
• Interfaces have the following characteristics and
  functions
• Connect routers to a network for packet entry and
  exit
• Can be on the motherboard or on a separate module
  

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Path Determination
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Internetwork Routers

• Any internetwork must include the following
• Consistent end-to-end addressing
• Addresses that represent network topologies
• Best path selection
• Dynamic or static routing
• Switching

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Academy Approach to Labs

• In the academy lab, all the networks will be
  connected with serial or Ethernet cables and the
  students can see and physically touch all the
  equipment.
• Devices that make up the WAN cloud are simulated
  by the connection between the back-to-back
  DTE-DCE cables.