Transcript Network Interface Layer Protocols

70-291: MCSE Guide to
Managing a Microsoft Windows
Server 2003 Network, Enhanced
Chapter 3:
TCP/IP Architecture
Objectives
• Describe the overall architecture of TCP/IP
• Identify application layer protocols in the TCP/IP
protocol suite
• Compare and contrast TCP/IP and UDP transport
layer protocols
• Understand the role of various Internet layer
protocols including IP, ICMP, and ARP
• Describe different network layer interface protocols
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TCP/IP Architecture Overview
• TCP/IP varies slightly from the standard OSI model
• Represented by a four-layer model
• Layers include:
• Application
• Transport
• Internet
• Network Interface
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TCP/IP Architecture Overview
(continued)
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TCP/IP Architecture Overview
(continued)
• Application layer provides access to network
resources
• Transport layer is responsible for preparing data to be
sent over the network
• Internet layer is responsible for logical addressing
and routing
• Network Interface layer consists of the network card
driver and the network card circuitry itself
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Application Layer Protocols
• Application layer accepts data from software and
sends it to the network
• There are many application layer protocols that are
only available on TCP/IP networks
• Each of these protocols is associated with a client
application and service
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HTTP
• Hypertext Transfer Protocol
• Most common protocol used on the Internet today
• Used by Web browsers and Web servers
• HTTP defines the commands that Web browsers can
send and how Web servers are capable of responding
• CGI, ISAPI, and NSAPI can be used to pass data
from a Web server to an application
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FTP
• File Transfer Protocol
• Simple file-sharing protocol
• Slowly becoming obsolete as HTTP can be used for
downloading/uploading files
• Protocol first introduced in the 1980s for UNIX
systems
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Activity 3-1: Using FTP to
Download a File
• Objective: Use FTP to download a utility
• Use the command line FTP utility to access
Microsoft’s FTP site: ftp.microsoft.com
• User Name: anonymous
• Password: Your e-mail address
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Telnet
• Terminal emulation program
• Primarily used to connect remotely to UNIX and
Linux machines
• Does not support a graphical user interface
• Many telnet clients can be connected to a server
concurrently
• Useful for administering UNIX and Linux systems
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SMTP
• Simple Mail Transfer Protocol
• Used to send and receive e-mail messages between email servers
• Protocol also used by e-mail client software such as
Microsoft Outlook
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Activity 3-2: Using Telnet to
Verify SMTP
• Objective: Use telnet to verify the functionality of an
SMTP server
• Connect to maila.microsoft.com on port 25 using
telnet
• Issue the help command to see the commands
supported by the server
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POP3
• Post Office Protocol version 3
• Most commonly used protocol for reading e-mail
messages
• Has commands to download and delete messages
from e-mail servers
• Does not support the sending of messages
• POP3 supports only a single inbox
• Does not support multiple folders for storage on the
server
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IMAP4
• Internet Message Access Protocol version 4
• Another protocol used to read e-mail messages
• Has abilities beyond those of POP3
• Can download message headers only
• Allows multiple folders on the server side
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Transport Layer Protocols
• These protocols are responsible for preparing data to
be sent over the network
• The most common task is to break information up
into packets
• Each transport layer protocol has its own set of ports
• An IP address and port number collectively form a
socket
• The port number ensures that a packet is delivered to
the correct service
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Transport Layer Protocols
(continued)
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Activity 3-3: Using Port Numbers
• Objective: Connect to resources using TCP and UDP
port numbers
• In this activity, you will be trying to connect to both
HTTP and FTP using different port numbers
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TCP
• Transmission Control Protocol is the most commonly
used transport layer protocol
• Connection oriented – a connection must be
established before data is transferred between
computers
• Connection is established using a three-way
handshake
• TCP tracks each packet to ensure it was successfully
delivered
• Packets are delivered using a sliding window
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Activity 3-4: Installing Network
Monitor
• Objective: Install network monitor to enable packet
capturing
• In this activity, you will be using network monitor to
see exactly how some of the data packets in your
network are addressed
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Activity 3-5: Viewing a TCP
Connection in Network Monitor
• Objective: Capture and view TCP connection packets
in Network Monitor
• In this exercise, you will be using Network Monitor
to view packets used when a TCP connection is
created with HTTP
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UDP
• User Datagram Protocol
• Not as common as TCP/IP
• UDP is connectionless and unreliable
• Streaming audio and video use this protocol
• Resolution of a DNS name is done via UDP
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Activity 3-6: Capturing UDP
Packets in Network Monitor
• Objective: Capture and view UDP packets in
Network Monitor
• This activity involves viewing DNS packets
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TCP versus UDP
• TCP is connection-oriented and reliable
• UDP is connectionless and unreliable
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Internet Layer Protocols
• Responsible for all tasks related to logical addressing
• An IP address is a logical address
• Protocols in this layer include: IP, RIP, OSPF, ICMP,
IGMP, and ARP
• Protocols in this layer are aware of other networks
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IP
• Internet Protocol is responsible for the logical
addressing of each packet created by the Transport
layer
• As each packet is sent out, IP attaches the source and
destination address to the packet
• IP verifies that, once the machine receives a packet
over the network, that packet has the same destination
address as the IP address of the computer
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RIP and OSPF
• Routing Information Protocol and Open Shortest Path
First
• Both are routing protocols
• Responsible for defining how paths are chosen
through the internetwork from one computer to
another
• Define how routers can share information about the
networks of which they are aware
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ICMP
• Internet Control Messaging Protocol
• Used to send IP error and control messages between
routers and hosts
• Most common use is the ping utility
• Ping is used to help determine if a computer is
functional and able to communicate over the network
• Internet Assigned Numbers Authority maintains a
complete list of ICMP packet types
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ICMP (continued)
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Activity 3-7: Testing Host
Functionality
• Objective: Test the functionality of a host using the
ping command
• You will be using the ping command to test Internet
connectivity
• Ping www.hotmail.com
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Activity 3-8: Viewing TTL
• Objective: View the TTL of a ping packet
• The ping utility shows the TTL of the packet, giving
an approximation for the speed of the connection
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IGMP
• Internet Group Management Protocol
• Used for the management of multicast groups
• Hosts use IGMP to inform routers of their
membership in multicast groups
• Routers use IGMP to announce that their networks
have members in particular multicast groups
• IGMP allows multicast packets to be distributed only
to routers that have interested hosts connected
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ARP
• Address Resolution Protocol
• Used to convert logical IP addresses to physical MAC
addresses
• Network cards use a MAC address to filter irrelevant
packets
• Data packets have four addresses: source IP address,
destination IP address, source MAC address, and
destination MAC address
• ARP uses a two-packet process to find the MAC
address of the destination computer
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ARP (continued)
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ARP (continued)
• ARP request
• First packet
• Broadcast to all computers on a local network, asking for
the MAC address of the computer with the destination IP
address
• Destination computer sees this packet and replies with the
address
• The communication process then proceeds
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ARP (continued)
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ARP (continued)
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ARP (continued)
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Activity 3-9: Viewing the ARP
Cache
• Objective: View the contents of the ARP cache
• In this exercise, the cache will be viewed and then
cleared to force the rebuilding of cache information
• Use the arp command to complete this activity
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Network Interface Layer
Protocols
• Most of the common Network Interface layer
protocols are defined by IEEE
• Ethernet is the most common Network Interface layer
protocol used in corporate networks today
• All varieties of Ethernet use Carrier Sense Multiple
Access/Collision Detection for access control
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Network Interface Layer
Protocols (continued)
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Network Interface Layer
Protocols (continued)
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Network Interface Layer
Protocols (continued)
• Token Ring is an older technology created by IBM
• Token Ring was commonly implemented with
mainframe computers
• Wireless LAN is one of the fastest growing network
types
• 802.11b defines the most common wireless standard
• Bluetooth is a short-range wireless communications
system
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Summary
• The TCP/IP model is composed of four layers:
Application, Transport, Internet, and Network
Interface
• Many Application layer protocols, each of which is
associated with a client application and service
• HTTP: most common protocol used on the Internet
• FTP is used for transferring files across the Internet
• Telnet: remote connect to UNIX and Linux systems
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Summary (continued)
• SMTP is used to send and receive e-mail messages
between e-mail servers
• POP3: most common protocol used for reading email messages
• IMAP4: another protocol used for reading e-mail
• The two Transport layer protocols are TCP and UDP
• TCP is connection-oriented and reliable
• UDP is connectionless and unreliable
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Summary (continued)
• Internet layer protocols:
• Responsible for tasks related to logical addressing
• All very specialized
• IP, RIP, OSPF, ICMP, IGMP, and ARP
• Ethernet: most common Network Interface layer
protocol used in corporate networks today
• Wireless LANs are one of the fastest growing
network types
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