IST 201

1
IST 201

• Chapter 5

2
LAN Technologies

• Ethernet most widely used technology in LANS
• In 1970, developed and implemented by
• Digital
• Intel
• Xerox
• IEEE 802.3 standard is based on the DIX
  specification.

3
Ethernet Specifications

• 802.3 Ethernet
• 802.3u FastEthernet
• 802.3z Gigabit Ethernet (Fiber)
• 802.3ab Gigabit Ethernet (UTP)
• 802.3ae 10 Gigabit Ethernet
• Layer 1 specification

4
Media

• Carries flow of information through a LAN
• Operates at Layer 1
• Cat 5 UTP primary media in Ethernet networks
• NIC Ports
• RJ45
• AUI attachment unit interface
• 15 pin connector
• Unusual
• Requires a transceiver to convert to RJ45

5
UTP Straight Through Cable

• One end ow o gw bl blw g brw br
• One end ow o gw bl blw g brw br
• 1 2 3 4 5 6 7 8

Transmit
Used forSwitch ? routerComputer ?
switchComputer ? hub
6
Crossover Cable

• 1 2 3 4 5 6 7 8
• One end ow o gw bl blw g brw br
• One end gw g ow bl blw o brw br
• 3 6 1 4 5 2 7 8

Used forRouter ? routerComputer ?
computerComputer ? routerSwitch ?
switchSwitch ? hub
7
Roll-over Cable

• 1 2 3 4 5 6
  7 8
• One end ow o gw bl blw g brw br
• One end br brw g blw bl gw o ow
• 8 7 6 5 4 3
  2 1

8
Hubs

• Multiport repeater
• Concentrators central connection point
• Active has power
• re-generates signal sends out all ports except
  receiving
• Intelligent active
• microchip w/diagnostics
• expensive
• good for troubleshooting
• Passive no power
• connection point
• does not regenerate the signal

9
5-4-3 Rule

• No more than 5 segments connect using 4 hubs
• Only 3 segments can have hosts
• Ensures that the signal reaches the destination
  within a specified time limit to avoid
  collisions..

10
Wireless

• RF
• Infrared req line of site
• Microwaves
• No wires
• Mobile
• Versatile
• Convenient

11
Bridges

• Data link layer
• Connects network segments
• Builds MAC table of hosts on each segment
• Filter looks at the destination MAC address,
  drops the frame if the destination is on the same
  segment.
• Flood doesnt have destination MAC address in
  the bridge table, sends out all ports except
  receiving one..
• Forward picks up frame and forwards out to the
  correct segment

12
Switch

• Multiport bridge
• Makes decisions based on MAC address
• Builds MAC table (switching table)
• Reduce traffic
• Increase bandwidth
• Filter
• Flood
• Forward

breaks up collision domain
13
NIC

• Printed circuit board providing network
  connectivity
• Operates _at_ layers 1 and 2 but it is considered a
  layer 2 device
• MAC address

14
Peer to Peer Networks

• Computers connected to act as equal partners
• No centralized administration
• Ea. computer may act as a server or client to
  other computers
• 10 or fewer
• Share files
• Share printers
• Easy to install
• Does not scale well
• Security is low

15
Client/Server

• Centralized control
• Common admin
• Increased security
• Scalable requires authentication
• Server additional processing power
• RAM
• Single point of failure

16
WANs

• Networks connected together over a
• wide geographic area.
• Use serial connections
• Bits of data are transmitted sequentially over a
  single channel
• Dedicated leased lines
• ISDN
• DSL
• Cable

17
Leased Lines

• T1 1.544 Mbps
• T3 44.736 Mbps
• Run PPP or Frame Relay Encapsulations
• PPP Point to Point Protocol
• Frame Relay

18
ISDN

• Integrated Services Digital Network
• 128 kbps
• Dial on demand connections
• BRI (Basic Rate Interface)
• 2 B channels (64 kbps bearer channels) - data
• 1 D channel (16 kbps delta channel) signaling
  and link management
• Typically uses PPP encapsulation.

19
DSL

• Digital Subscriber Line
• 128 kbps 6.1 Mbps
• Dial-up connectivity
• Uses telephone infrastructure

20
Cable

• Up to 8 Mbps (maybe higher?)
• Uses existing cable tv infrastructure
• Coaxial cable

21
Router Purpose

• Route packets from source to destination with a
  LAN
• Provide connectivity from the LAN to the WAN.
• Segments a network into subnetworks
• Breaks up broadcast domains.

22
Router WAN Serial Ports

• V.35 connectors
• DTE (data terminal equipment) on the customer
  side of the connection
• DCE (data circuit-terminating equipment) on the
  ISP side.
• Provides clock rate
• CSU/DSU channel service unit/data service unit
• Another device that provides clocking with a
  direct connection.

23
Configuring the Router

• Need management connection
• Roll-over cable/console cable
• Connects serial port of computer using DB9 to
  RJ45 transceiver to Console port (RJ45) on the
  router
• Terminal emulation software
• Hyperterminal w/these settings on the COM port
• 9600 bps
• 8 data bits
• No parity
• 1 stop bit
• None

24
Console v. Auxiliary Port

• Console port is used for initial router
  configuration
• Console management connection is between a pc and
  the router console port.
• Management via a modem connection is possible for
  configuration changes.
• Modem is connected to the auxiliary port

25
Cisco 2500 Router

• DB-15 port
• Requires a transceiver to convert to a Ethernet
  port (RJ45)