Transcript CCNA1 Chapter 1

CABLING
LANs & WANs
Module 5
Semester I
Module 5 – Cabling LANs & WANs
Content
• Cabling the LAN
• Cabling the WAN
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Module 5 – Cabling LANs & WANs
Objectives
• Identify characteristics of Ethernet networks.
• Identify straight-through, crossover, and rollover cables.
• Describe the function, advantages, and disadvantages of
repeaters, hubs, bridges, switches, and wireless network
components.
• Describe the function of peer-to-peer networks.
• Describe the function, advantages, and disadvantages of
client-server networks.
• Describe and differentiate between serial, Integrated
Services Digital Network (ISDN), digital subscriber line (DSL),
and cable modem WAN connections.
• Identify router serial ports, cables, and connectors.
• Identify and describe the placement of equipment used in
various WAN configurations.
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Cabling the LAN
The Physical Layer
Module 5 – Cabling LANs & WANs
Networking Media
Carry flow of information
Media Characteristics:
Cable length
Cost
Ease of installation
Susceptibility to interference
Media Types
•Coaxial
•Fiber Optic
•Space
Category 5 unshielded twisted-pair
cable (Cat 5 UTP)
A subset of
physical layer
implementations
for Ethernet
LANs
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Module 5 – Cabling LANs & WANs
Ethernet Media
Ethernet technologies can be used in a campus network
in several different ways:
• 10 Mbps at the user level to provide good performance.
• 100 Mbps for clients or servers that require more bandwidth.
• Fast or Gigabit Ethernet between backbone devices.
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Media Connectors
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RJ-45 connectors
This is the
Jack
This is the
Connector
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568B pin assignments – straight cable
Transmit Data
Tip +ve
Receive Data
Ring -ve
Transmit Data
Ring -ve
Receive Data
Tip +ve
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Cross Over cable – pin assignments
568B
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Module 5 – Cabling LANs & WANs
Interconnecting Devices
Use straight-through cables for…
•Switch to router
•Switch to PC or server
•Hub to PC or server
Use roll-over cables to…
•Connect a terminal to a
console port
Use crossover cables for…
•Switch to switch
•Switch to hub
•Hub to hub
•Router to router
•PC to PC
•Router to PC
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LAN Devices
Repeaters, Hubs, Bridges, Switches
Module 5 – Cabling LANs & WANs
Repeaters - Hubs
Repeaters
• A repeater regenerates and retimes network signals at the bit level to
allow them to travel a longer distance
• 5-4-3 Rule for 10-Mbps Ethernet should be used to limit latency
• Too much latency on the LAN increases the number of latecollisions
and makes the LAN less efficient
Hubs
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1.
2.
3.
Hubs are actually multiport repeaters
Change the network topology from a linear bus to a star
Three basic types:
Passive – no boost, no clean and no power
Active - needs power to amplify the incoming signal
Intelligent - microprocessor chip and diagnostic capabilities
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Module 5 – Cabling LANs & WANs
Bridges & Switches
Bridges
• Bridges and switches operate at the Data Link layer.
• Destination MAC address is looked up in the bridge table to
determine whether to filter, flood, or copy the frame onto another
segment.
Switches
•
•
•
A switch has many ports with many network segments connected to them.
A switch chooses the port to which the destination device is connected.
Alleviates congestion in LANs by reducing the size of collision domains,
reducing traffic and increasing bandwidth.
Two basic operations:
1. Switching data frames.
2. Build and maintain switching tables and search for loops.
Switches operate at much higher speeds than bridges and can support new
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functionality, such as virtual LANs.
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Module 5 – Cabling LANs & WANs
Wireless
Much less cabling
RF, IR, laser, satellite, microwaves
 The only cabling can be to the Access Points
 The transmitter converts source data to EM waves
 The receiver converts waves back into data
 All devices in WLAN must have Wireless NICs
IR weaknesses:
 ‘Line of sight’ limitation (newer technologies combat this)
 Signal weakening or obstruction by people or humidity
RF technology works between rooms or even buildings
RF weaknesses:
 Single frequency is subject to outside interference and obstructions
 Single frequency is easily monitored by others making it insecure
FHSS and DSSS are Spread Spectrum technologies which add security
and immunity to noise by using multiple frequencies
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NIC
The function of a NIC is to connect a host device to the
network medium
The NIC is also referred to as a network adapter
NICs are considered Layer 2 devices because each NIC
carries a unique code called a MAC address
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Module 5 – Cabling LANs & WANs
Network Environments
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Module 5 – Cabling LANs & WANs
Peer-to-Peer
In a peer-to-peer network
• networked computers act as equal partners, or
peers
• individual users control their own resources
Peer-to-peer networks are relatively easy to install and
operate
A peer-to-peer network works well with 10 or fewer
computers
peer-to-peer networks do not scale well, their efficiency
decreases rapidly as the number of computers on the
network increases
Security is difficult to maintain
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Module 5 – Cabling LANs & WANs
Client/Server
In a client/server arrangement, network services are
located on a dedicated computer called a server
The server is a central computer that is continuously
available to respond to requests from clients for file,
print, and application services
Servers are designed to handle requests from many
clients simultaneously
The aggregation of resources on server systems brings
greater security, simpler access and coordinated
control, the server introduces a single point of failure
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Module 5 – Cabling LANs & WANs
Peer-to-Peer vs. Client/Server
Advantages
Advantages of a Peer-to-Peer
Network
Advantages of a
Client/Server Network
Less expensive to implement
Provides for better security
Does not require additional
specialized network
administration software
Easier to administer when the
network is large due to
centralized administration
Does not require a dedicated
network administrator
All data can be backed up on
one central location
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Peer-to-Peer vs. Client/Server
Disadvantages
Disadvantages of a Peer-to-Peer
Network
Disadvantages of a Client/Server
Network
Does not scale well to a large
networks and administration
becomes unmanageable
Requires expensive specialized
network administrative and
operational software
Each user must be trained to
perform administrative tasks
Requires expensive, more powerful
hardware for the server machine
Less secure
Requires a professional
administrator
All machines sharing resources
negatively impacts performance
Has a single point of failure. User
data is unavailable if the server is
down
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Module 5 – Cabling LANs & WANs
WAN Connections
Serial connections are used to support WAN services such as
dedicated leased lines that run Point-to-Point Protocol (PPP) or
Frame Relay
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Module 5 – Cabling LANs & WANs
WAN
WANs use serial transmission
This is a process by which bits of data are sent over a
single channel
This process provides reliable long distance
communication and the use of a specific
electromagnetic or optical frequency range
Signals transmitted over voice grade telephone lines use
3 kilohertz (kHz).
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Module 5 – Cabling LANs & WANs
WAN
Serial connections are used to support WAN services
such as dedicated leased lines that run Point-to-Point
Protocol (PPP) or Frame Relay
ISDN offers dial-on-demand connections or dial backup
services.
• ISDN Basic Rate Interface (BRI) is composed of:
Two 64 kbps bearer channels (B channels) for
data
One delta channel (D channel) at 16 kbps used
for signaling and other link-management tasks
• PPP is typically used to carry data over the B
channels.
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Router Connections
Cisco router physical connectivity is provided by serial connections:
• The first type of serial connections is a 60-pin connector
• The second is a more compact ‘smart serial’ connector
The provider connector will vary depending on the type of service
equipment
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Module 5 – Cabling LANs & WANs
DTE/DCE
When the connection is made directly to a service provider, or a
device that provides signal clocking such as a channel/data
service unit (CSU/DSU), the router will be a data terminal
equipment (DTE) and use a DTE serial cable.
When the local router is required to provide the clocking rate it will
use a data communications equipment (DCE) cable
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Router Connection Points
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Module 5 – Cabling LANs & WANs
Managing Routers
To initially configure the Cisco device, a management
connection must be directly connected to the device
The console port allows monitoring and configuration of
a Cisco hub, switch, or router
The cable used between a terminal and a console port
is a rollover cable
also known as a console cable
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Module 5 – Cabling LANs & WANs
Console Connection
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LABS
Module 5 – Cabling LANs & WANs
LABS
5.1.5 RJ-45 jack punch down
5.1.7 Hub & NIC purchase
5.1.10 Purchasing LAN Switches
5.1.12 Building a Peer to Peer network
5.1.13a Building a HUB based network
5.1.13b Building a Switch based network
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