Transcript Connecting to the Network

Connecting to the
Network
Networking for Home and Small Businesses – Chapter 3
What is a network?
 The ability to connect people and equipment no matter
where they are in the world.
– telephone
– computers
– television
 How does your body work as a network??
Networking and Its Benefits
A CONVERGED NETWORK!!!
Networks = Sharing Resources
 Main reason for networking – sharing resources
– File sharing – Why disable- allows more security
– Print sharing
 Consider this before sharing:
– security issues
– permissions granted
 Windows XP users
– use Simple File Sharing
Networking and Its Benefits
 SOHO Network
– Small Office/Home Office
Networking and Its Benefits
 Define the components of an Information network
 Hosts
– PCs
– send and receive information across the network
–connected to a network device
 Peripherals
– not directly connected to the network, but connected to hosts
 Network devices
– hub, switch, router
 Network media
– used to connect hosts/devices
Networking and Its Benefits
 Clients and servers
– software installed determines the role of a client or a server
 Server software
– enables the server to provide information to other hosts
 Client software
– enables the client to request and display information from the
server
– Example: Internet Explorer
Networking and Its Benefits
 Build computer peer-to-peer network and verify
 The ability to act as both a client and server
Networking and Its Benefits
Schools,
Corporations
Internet
Network Topologies
 Physical topology (Blueprint of a network)
– created to record where each host is on the network
– shows how each host is connected (media, devices, etc)
Network Topologies
 Logical topology (Behind The Scenes Information)
– how the host uses the network
– host names, addresses, groups, applications
Physical and Logical Network Development
 Using the handout (online within Mr. Smith’s
webpage)as a guide and your creativity, design the
physical and logical topology for ABC Banking Center.
 Please read the entire handout before beginning as
important information is contained throughout and will
need to be understood before making your first decision
on the overall design.
 Project is worth a 250 points.
Business Equipment Purchase Task
 Using the handout with the specifications for the ABC
Banking Center research components that will be used
to help form a complete computer network.
 When finished please submit for a 200 point grade.
 Two sites will be utilized 1) www.cdw.com and 2)
www.newegg.com
Communication Protocols
 Primary purpose of a network – to communicate & share
 Elements of communication
– Sender (source)
• has a need to communicate
– Receiver (destination)
• receives message and interprets it
– Channel
• pathway for information to travel
Successful delivery of the message
 Rules (protocols) must be followed:
– Identification of the sender and/or receiver
– Channel in which to communicate (face-to-face)
– Mode of communication (written or spoken)
– Language
– Grammar
– Speed or timing
Communication Protocols
 Encoding vs. Decoding
 Encoding
– Humans
• converting thoughts into language, symbols, or sounds
– Computers
• messages converted into bits
• each bit encoded into sound, light, or electrical impulses
• destination host then decodes
 Decoding
– reverse of encoding
In Class Task
 Can you encode and decode. Try to decode the
messages provided and then encode a message of
your own.
Communication Protocols
 Messages have size restrictions depending on the
channel used
 If the message is broken into smaller pieces, it is easier
to understand
 If the message is too long or too short, will be
considered undeliverable.
Communication Protocols
 Message Patterns
Unicast – single destination
Multicast – same message to a group
Broadcast – all hosts need to receive the message
 Encapsulation
– placing the letter into the envelope(one message format into
another message format so that it can be delivered)
 Go to page 3.2.7.1 to see the various message patterns
Communication Protocols
PROTOCOLS = RULES TO FOLLOW
Communication Across a Local Ethernet
Network
 Computers must speak the same language in order to
communicate!!
Standards in technology
 Standards – rules by which equipment from different
vendors operate
 Benefits of standards:
–Simplify new product development
– Promote competition
– Provides consistent interconnections across networks
Communication Across a Local Ethernet
Network
 IEEE (Institute of Electrical and Electronic Engineers)
– maintains networking standards
– 802.3 – Ethernet standard
 A breakdown of terminology
– 100 Base-T
– 100 = Speed in Mbps-**SPEED
– Base = Baseband transmission**Transmission Type
– T = Twisted Pair**Type Of Media
Communication Across a Local Ethernet
Network
 Ethernet communication
– each device has a MAC address
– each device may look at the data, but only the device that
matches the destination MAC will respond
–NIC will look at the destination MAC address and decide if
it will accept a frame.
The Ethernet Frame (3.3.4.1 for image)
 Preamble – beginning of the timing
 SFD (Start Frame Delimiter) – marks the end of the timing, but
beginning of the frame
 Destination MAC
 Source MAC **Only MAC Addresses are used in Ethernet Frames**
 Length/Type
– Length – tells which protocol receives the data
– Type – number of bytes of data
 Encapsulation –information to be sent
 FCS (Frame Check Sequence) – checks for damaged frames/errors
Activity
 Go to page 3.3.4.2 and complete the activity using the
Ethernet frame
Logical Addressing
 MAC vs. IP
 IP Address (Logical Address)
– assigned based on where the host is located
– assigned by the administrator
 Logical Addresses (IP Addresses) are used to help determine the
network a host is located on
 Parts of an IP address
– Network – same for all hosts connected to the LAN
– Host – unique to each host on the network
 MAC Address (Physical Address)
–Assigned by the designer of the NIC within a computer
–Used to identify the exact machine that is needed within a network.
MAC Address Lab
 Complete the lab on page 3.3.3.2 and write down all
answers to the questions that are posed on a sheet of
paper. Please skip over step Step 4 Question C as this
will cause your screen and computer to be blocked by
IMPERO.
The Hierarchical Design Structure
 Divided into three layers
– Access Layer
• connection to the hosts
– Distribution Layer
• interconnects smaller networks
– Core Layer
• high speed connection between
distribution devices
Access Layer Devices
 Most basic level
 Made up of:
– host devices
– first line of networking devices
– hub, switch, workstations-the entry level devices
Access Layer Device – A HUB
 Accepts data signal from one port and sends it out all
ports
 Collisions
– results in message being garbled and unreadable
– occur when two or more hosts send a message at the same
time (undesirable in a network)
 NOT VERY SMART
– a hub does not make decisions
Hubs And Collision Domains
 Collision domain – area where information runs into
others pieces of information. Collision domains can be
broken up by the following devices 1)Router,2)Switch
3) Bridge
 More collision domains = better performance
 How many collision domains exist in the graphic
shown?
Hub Activity
 3.4.2.3 within the Cisco curriculum
Access Layer Device – A SWITCH
 SMARTER THAN A HUB (Look at 3.4.3.1)
 dedicated bandwidth out each port
 sends info to the intended recipients only!!
 Can forward messages to a specific host by looking in
its MAC table
 If destination MAC is not in its MAC table,a switch sends out a
request.
 Only the host with the correct MAC address will respond
Collision Domain
 Collision Domains
– each port on a switch is its own collision domain
– 8 port switch = 8 collision domains
Switch Activity
 3.4.3.4 from the Cisco curriculum
Broadcasts
 If there is only one destination MAC in a message, how
can you contact everyone else?
– send a broadcast MAC
– hexidecimal digits FFFF.FFFF.FFFF represent a broadcast
 Useful when hosts need to send information but don’t
know what hosts are to receive it
 Switches and hubs send the broadcast out to everyone
on their network. (Broadcast Domain)
ARP Request
 Sent when the sending host knows the destination IP,
but not the MAC
 Will discover the MAC address of any local host on the
network
Distribution Layer Devices—The Router
 Routers – directs traffic based on the destination IP
address
 Routers build routing tables; to help make decisions
about which port to send information.
 Look only the network portion of the IP address
– finds the best path to take to get to the destination
 Routers do not forward broadcasts, it keeps them
contained!!!
Distribution Layer Devices—The Router
 What does a router do after it determines that a data
packet from Network 1 should be forwarded to Network
2?
- It reassembles the frame with different MAC addresses than
the original frame.
Default Gateway
 Used when a host wants to send data to a host on a different
network. An incorrect default gateway can stop all traffic from
leaving the original network. Local computers and hosts can
communicate but will not be able to communicate with anyone
outside of the network.
 The device commonly used as the default gateway is the router
interface closest to the computer
Complete the activity on page 3.5.3.2 using default gateways
Types of Routing
 Dynamic
– information is obtained from neighboring routers
 Static
– manually entered by the network administrator
 What happen to a message that is not in the routing table?
– It is dropped unless . . .
 A default route is set
– “last resort” type of router
– will send it to the router it thinks may be have the destination IP
–Used of no route is found in the routing table
The Layers
 Go to page 3.3.7.2 and use your new knowledge over
the three layers to answer 4 scenario questions.
Multifunction Devices
 Integrated routers
– Linksys wireless router
– problem = single point of failure
 Cisco Integrated Services Router (ISR)
– performs services of three different devices
• router
• switch
• wireless access point