chapter 3 ccna discovery encapsulation - explanations and clarifications ccna discovery...
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Chapter 3Chapter 3
CCNA DiscoveryEncapsulation - Explanations
and Clarifications
CCNA DiscoveryEncapsulation - Explanations
and Clarifications
Why Network?Why Network?
• Share resources• Files• Internet Connections• Printers• Scanners• Email• IM
• Share resources• Files• Internet Connections• Printers• Scanners• Email• IM
Define the PiecesDefine the Pieces
• Hosts• PC’s• Send and Receive Information• Directly connected to a Network
Device
• Hosts• PC’s• Send and Receive Information• Directly connected to a Network
Device
Define the PiecesDefine the Pieces
• Peripherals• Not directly connected to the
Network, but are connected through a PC.
• Peripherals• Not directly connected to the
Network, but are connected through a PC.
Define the PiecesDefine the Pieces
• Network Devices• Hub
• - Dumb device• Whatever goes in one port comes out all ports
• Switch• - Smart Device
• Connects only to the target device by using a lookup table
• Uses MAC addresses
• Network Devices• Hub
• - Dumb device• Whatever goes in one port comes out all ports
• Switch• - Smart Device
• Connects only to the target device by using a lookup table
• Uses MAC addresses
Hub vs. SwitchHub vs. Switch• 1 Collision
Domain for the Entire Device
• One Way Communication
• No Routing Table
• 1 Collision Domain for the Entire Device
• One Way Communication
• No Routing Table
• Each Port is a Collision Domain• (Private Line)
• Two-way (Full Duplex) Communications
• Routing Table
• Each Port is a Collision Domain• (Private Line)
• Two-way (Full Duplex) Communications
• Routing Table
Define the PiecesDefine the Pieces
• Router• The major traffic cop• Forwards by using IP Addresses• Blocks Broadcasts• This is what makes the Internet work
• Very Smart Routing• Re-Routes traffic based upon
changing conditions.
• Router• The major traffic cop• Forwards by using IP Addresses• Blocks Broadcasts• This is what makes the Internet work
• Very Smart Routing• Re-Routes traffic based upon
changing conditions.
Define the PiecesDefine the Pieces
• Network Media• Carries the Data• Connects Hosts and Devices• Copper Wire• Fiber• Wireless
• Network Media• Carries the Data• Connects Hosts and Devices• Copper Wire• Fiber• Wireless
2 Types of Networks2 Types of Networks
• Peer to Peer• No centralized administration or
control• Administered Network• Centralized Server• System Administrator controls
access to services/resources
• Peer to Peer• No centralized administration or
control• Administered Network• Centralized Server• System Administrator controls
access to services/resources
2 Ways to Map a Network
2 Ways to Map a Network
• Physical• Shows where devices are
physically located• Shows how devices are connected
• Physical• Shows where devices are
physically located• Shows how devices are connected
2 Ways to Map a Network
2 Ways to Map a Network
• Logical• Shows how the host uses the network• Shows Host Names, IP Addresses,
Groups and Applications
• Logical• Shows how the host uses the network• Shows Host Names, IP Addresses,
Groups and Applications
How Files are MovedHow Files are Moved• Each Chunk called a “Packet” is
individually acknowledged.• If it is damaged or missing the receiving
computer requests that it be resent.• At the simplest level the header includes
the number of bits in the packet. If the count is off an error is assumed.
• Each Chunk called a “Packet” is individually acknowledged.
• If it is damaged or missing the receiving computer requests that it be resent.
• At the simplest level the header includes the number of bits in the packet. If the count is off an error is assumed.
How Files Are MovedHow Files Are Moved• Files are first broken down into packets• That way is a piece needs to be resent due
to an error, it wil be smaller and faster.• Then they are encapsulated.• Headers and footers are added to indicate
sender and receiver.• Packets are numbered so they can be
identified for reassembly.• They may not arrive in order.
• Files are first broken down into packets• That way is a piece needs to be resent due
to an error, it wil be smaller and faster.• Then they are encapsulated.• Headers and footers are added to indicate
sender and receiver.• Packets are numbered so they can be
identified for reassembly.• They may not arrive in order.
RulesRules
• Rules are applied to control how data is organized.
• The term for these rules is a “protocol”.
• Every manufacturer must follow these rules so that all devices can communicate.
• Rules are applied to control how data is organized.
• The term for these rules is a “protocol”.
• Every manufacturer must follow these rules so that all devices can communicate.
RulesRules• Parts of a Packet• Destination MAC Address• Source MAC address (Last Hop)• Start Flag• Recipient Identifier• Sender Identifier• Data• End of Packet indicator
• Parts of a Packet• Destination MAC Address• Source MAC address (Last Hop)• Start Flag• Recipient Identifier• Sender Identifier• Data• End of Packet indicator
EncapsulationEncapsulation• Turning a chunk of data into a packet
to be sent is called encapsulation. • This encoding process is then followed
by de-encoding on the other end.• Think of putting a letter into an
envelope, then removing it from the envelope in order to read it.
• Turning a chunk of data into a packet to be sent is called encapsulation.
• This encoding process is then followed by de-encoding on the other end.
• Think of putting a letter into an envelope, then removing it from the envelope in order to read it.