1 / 17

WAN is a data communications network that operates beyond a LAN’s geographic scope.

WAN is a data communications network that operates beyond a LAN’s geographic scope. One must subscribe to a WAN provider such as AT&T, Sprint, RBOC. They provide network services such as: Frame Relay Integrated Services Digital Network (ISDN) Asynchronous Transfer Mode (ATM)

hinda
Télécharger la présentation

WAN is a data communications network that operates beyond a LAN’s geographic scope.

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. WAN is a data communications network that operates beyond a LAN’s geographic scope. • One must subscribe to a WAN provider such as AT&T, Sprint, RBOC. They provide network services such as: • Frame Relay • Integrated Services Digital Network (ISDN) • Asynchronous Transfer Mode (ATM) • Which carries traffic type of voice, data and video. • In general, WAN’s operate at the 1st three layers of the OSI. (Though Frame Relay actually operates at layer 1 and layer 2.) So all of the WAN services have layer 1 & layer 2 in common. • Other characteristics of WAN are: • operate beyond LAN geographic area • use serial connections • provide full-time & part-time connectivity

  2. Router’s Internal Components • The main internal components of the router are: • Random Access Memory (RAM) • Nonvolatile Random-Access Memory (NVRAM) • flash memory • Read-Only Memory (ROM) • Interfaces

  3. Router’s Internal Components • RAM: • stores routing tables • holds ARP cache • holds fast-switching cache • performs packet buffering • maintains packet-hold queues • provides temporary memory for the configuration file of the router while the router is powered on • loses content when router is powered down or restarted

  4. Router’s Internal Components • NVRAM: • provides storage for the startup configuration file • retains content when router is powered down or restarted

  5. Router’s Internal Components • Flash memory: • holds the operating system image (IOS) • allows software to be updated without removing & replacing chips on the processor • retains content when router is powered down or restarted • can store multiple versions of IOS software • is electronically erasable, programmable ROM (EEPROM)

  6. Router’s Internal Components • ROM: • maintains instructions for power-on self test (POST) diagnostics • stores bootstrap program & basic operating system software • requires replacing pluggable chips on the motherboard for software upgrades

  7. Router’s Internal Components • Interfaces: • connect router to network for frame entry & exit • can be on the motherboard or on a separate module • connect the router to LANs and WANs

  8. Subscriber to Provider Interface Modem Router DCE DTE A key interface in the customer site occurs between the Data Terminal Equipment (DTE) such as a router to the Data Circuit-Terminating equipment (DCE) to the WAN network such as a modem. DTE is on the customer’s side of the network. The DCE is a modem and in many cases is circuitry in a CO, switch which is made up of a CSU/DSU (Channel Service Unit/Data Service Unit). The major reason for CSU/DSU is to protect the equipment from CPE/DTE from aberrant voltages, and to ‘square’ up the signal. DCE is usually on the provider’s side.

  9. Subscriber to Provider Interface EIA/TIA-232, V.35, X.21, HSSI, others Modem Router DCE DTE

  10. Routers Physical Characteristics • The 3 basic types of connections on a router are: • LAN interfaces • WAN interfaces • Management ports • Console • auxiliary

  11. Routers Physical Characteristics • Management ports provide • Text-based connection • Configuration, monitoring, password recovery and troubleshooting • The management ports: • EIA-232 asynchronous serial ports • used for non-network connections • used for initial router configuration • to connect to a port, a PC must have a terminal emulation program • rollover cable from PC to the management ports

  12. Management Ports • The console port, says Cisco is preferred when troubleshooting: • doesn’t depend on network services • displays start and error messages by default • To establish a connection between PC and a router, one needs • terminal emulation software • rollover cable • RJ-45 to DB-9 connector

  13. Routers Physical Characteristics • Cisco says, the terminal emulation software, HyperTerminal, the parameters used to configure a router are: • Data bits • Stop bits • parity

  14. Router’s connection LAN & WAN • For a PC of a LAN to connect to a router, one • straight-thru cable from the PC to a HUB or switch • straight-thru cable from the HUB or switch to router’s Ethernet interface

  15. Router’s connection LAN & WAN • An internetwork must include: • switching • dynamic or static routing • consistent end-to-end addressing

  16. Router’s connection to LAN & WAN EIA/TIA-232, V.35, X.21, HSSI, others Modem Router DCE DTE • The connections to WAN on router is through the serial interface, either as a Smart Serial interface connector or DB-60 connector. • The following devices are used in the construction of a WAN: • communication servers • routers • modems

  17. Router vs. PC • Cisco says the common components between a router and PC are: • CPU • input/output interfaces • system bus

More Related