Hubs
ƒ Connects other devices, concentrates the cabling
ƒ Transmits the signal out of all ports except the
one it entered on – called Flooding
ƒ Logical bus topology
Planning and Cabling
Networks
Multi access
Shared bandwidth
ƒ Interconnected hubs
remain a single
collision domain.
Half duplex
Network Fundamentals – Chapter 10
ITE PC v4.0
Chapter 1
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LAN Switches
Routers
ƒ Routers are used to
interconnect networks
ƒ Selective forwarding
ƒ Each port is a separate
collision domain –
reduces the number of
collisions
ƒ They break up broadcast
domains and collision
domains
ƒ Floods broadcasts
ƒ They can interconnect
networks that use
different technologies
ƒ Can be used to interconnect network
segments of different speeds – 10 Mbps, 100
Mbps, 1Gbps
ƒ They can have both LAN
and WAN interfaces
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Selecting a device for a LAN
Factors to Consider in Choosing a Switch
ƒ Cost
ƒ Speed and Types of Ports/Interfaces
ƒ Speed and Types of Ports/Interfaces
ƒ Newer computers with built-in 10/100/1000
Mbps NICs are available
ƒ Expandability
ƒ How many ports, UTP or fibre, plan for future.
ƒ Manageability
ƒ Number of switches to
ƒ Additional Features and Services
Reduce cable length
Cover the area
Redundancy
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Switch Redundancy
Factors to Consider in Choosing a Router
ƒ Cost and interface types.
ƒ Expandability
ƒ Media
ƒ Operating System features:
Security
Quality of Service (QoS)
Voice over IP (VoIP)
Routing multiple Layer 3 protocols
Special services, e.g. NAT and DHCP
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LAN Cabling
ƒ Telecommunications room
Also known as the Distribution Facility
Contains racks and interconnection devices
May contain servers
ƒ Horizontal cabling
Also known as Distribution cabling
Connects work areas to distribution facility
ƒ Vertical cabling
Also known as Backbone cabling
Connects the distribution facilities
UTP – Basic Cabling Media
ƒ ANSI/TIA/EIA-568-B standard.
ƒ Maximum total cable length 100m.
ƒ 5 meters max of patch cable for interconnecting
patch panels
ƒ 5 meters max of cable from the cable termination
point on the wall to the telephone or computer
ƒ 90 meters max horizontal cabling
ƒ Cross-connecting point or Patch Panel
Crossover or Straight-thru cables?
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Crossover UTP Cable
ƒ Pinouts: one end EIA/TIA T568A and the other
T568B
ƒ Use crossover when connecting the same type of
devices:
Switch to switch
Switch to hub
Hub to hub
Router to Router (via Ethernet port connection)
Computer to computer
Computer to a Router (Ethernet port)
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ƒ LAN connectivity devices - hubs or switches - use
MDIX (media-dependent interface, crossover)
connections.
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Straight-through UTP Cable
ƒ Pinouts: EIA/TIA T568A at both ends
Or EIA/TIA T568B at both ends
ƒ Use straight-thru when connecting devices via a
hub or switch
ƒ MDI (media-dependent interface) uses the normal
Ethernet pinout. Devices such as computers,
servers, or routers
WAN Connections
Serial DTE and DCE WAN Connections
WAN
Data Terminal Equipment:
V.35
Serial
cable
Also DB-60
connector
ƒ End-user’s device on the
WAN link
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Data Communications
Equipment:
ƒ End of the WAN
providers side of the
WAN link
ƒ Provides the clocking
signal
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Network Design –
Developing an Addressing Scheme
Device Management Connection
ƒ Console port connection
Include future
requirements
ƒ Uses Rollover cable
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Determine the optimum number of sub
networks in the larger internetwork
Count the segments between router interfaces.
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Devise an Addressing Scheme
ƒ Why divide a network into subnets?
Manage broadcast domains
Different network requirements
Security
ƒ Addressing scheme
A unique subnet address and subnet mask for
each subnet
A range of usable host addresses for each subnet
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10.4.1
ƒ The maximum number of hosts on one network or
subnet is calculated using the formula (2^n - 2)
where n is the number of host bits in the address
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10.4.2
172.16.0.0 /22
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