Transcript Internet Layer Protocols

Hands-On Microsoft
Windows Server 2003
Networking
Chapter Three
TCP/IP Architecture
Objectives
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Describe the overall architecture of TCP/IP
Describe application layer protocols
Discuss transport layer protocols
Understand the role of various network layer
protocols including IP, ICMP, and ARP
• Understand network interface layer protocols
• Describe different physical layer protocols
• Discuss changes to IP introduced with IPv6
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TCP/IP Model
• Application layer
– Provides access to network resources
– Defines rules, commands, and procedures
• Transport layer
– Breaks large messages into smaller packets of
information
– Tracks whether packets arrived at final
destination
• Internet layer
– Responsible for logical addressing
• Networking interface layer
– Consists of network card driver and circuitry on
network card itself
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TCP/IP Architecture
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Hypertext Transfer Protocol (HTTP)
• The most common protocol used on the Internet
today
• Defines the commands that Web browsers can
send and how Web servers are capable of
responding
• Common mechanisms for passing data from a
Web server to an application
– Common Gateway Interface (CGI)
– Internet Server Application Programmer Interface
(ISAPI)
– Netscape Server Application Programmer
Interface (NSAPI)
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File Transfer Protocol (FTP)
• A simple file-sharing protocol
• Includes commands for uploading and
downloading files
• Implemented in stand-alone FTP clients as well
as in Web browsers
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Telnet
• A terminal emulation protocol used to remotely
connect to Unix and Linux Systems
• Does not support a graphical user interface
(GUI), only text
• Telnet client only responsible for displaying
information on the screen and passing input to
the server
• Can have many telnet clients connected to a
single server at one time
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Simple Mail Transfer Protocol
(SMTP)
• Used to send and receive e-mail messages
between e-mail servers
• Used by e-mail client software, such as Outlook
Express, to send messages to the server
• Is never used to retrieve e-mail that is being
read
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Post Office Protocol version 3
(POP3)
• The most common protocol used for reading email messages
• Does not support sending messages
• Only supports a single inbox and does not
support multiple folders for storage on the server
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Internet Message Access Protocol
version 4 (IMAP4)
• Another common protocol used to read e-mail
messages
• Allows for multiple folders on the server side to
store messages
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Transport Layer Protocols
• Responsible for getting data ready to move
across the network
• Port
– Used by transport layer protocols to direct
network information to the proper service
• Transport layer protocols in the TCP/IP protocol
suite
– Transmission Control Protocol (TCP)
– User Datagram Protocol (UDP)
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Common Services and Ports
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Transmission Control Protocol (TCP)
• The most commonly used transport layer
protocol
• Connection-oriented and reliable
• Establishment of a connection is a three-packet
process between the source and destination
host
• Syn bit
– Indicates that the packet is a request to negotiate
a connection
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Transmission Control Protocol (TCP)
(Continued)
• Ack bit
– An option in a packet that indicates this packet is
a response to the first packet
• Sliding Window
– Process used to track which packets have been
received by the destination host
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TCP Three-way Handshake
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User Datagram Protocol (UDP)
• Connectionless and unreliable
• Has no sliding window
• The appropriate transport layer protocol to use
when you are unconcerned about missing
packets
• Use also when the amount of data being
exchanged is very small
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Internet Layer Protocols
• Responsible for all tasks related to logical
addressing
• Internet Protocol (IP)
– Responsible for the logical addressing of each
packet created by the transport layer
• Routing Information Protocol (RIP) and Open
Shortest Path First (OSPF)
– Responsible for defining how paths are chosen
through the internetwork from one computer to
another
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Internet Layer Protocols (Continued)
• Internet Control Messaging Protocol (ICMP)
– Used to send IP error and control messages
between routers and hosts
– Ping utility uses ICMP packets to test connectivity
between hosts
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Common ICMP Packet Types
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Internet Layer Protocols (Continued)
• Internet Group Management Protocol (IGMP)
– Used for the management of multicast groups
• Address Resolution Protocol (ARP)
– Used to convert logical IP addresses to physical
MAC addresses
– Data packets have four addresses:
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Source IP address
Destination IP address
Source MAC address
Destination MAC address
– Uses a two-packet process to find the MAC
address of the destination computer
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Computer A communicates with
Computer B
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ARP Request Packet
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ARP Reply Packet
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Communication Across a Router
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Network Interface Layer Protocols
• Institute of Electrical and Electronics Engineers
(IEEE)
– Has system of numbered committees that each
defines a different network interface layer
protocol
• Ethernet
– The most common network interface layer
protocol used in corporate networks today
• Token Ring
– Was commonly implemented with mainframe
computers
– Uses twisted pair cabling and operates at 4 Mbps
or 16 Mbps
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Network Interface Layer Protocols
(Continued)
• Wireless LAN
– One of the fastest growing network types
– 802.11b standard defines the most common
wireless standard
• Bluetooth
– Short-range wireless communication system
– Has maximum distance of approximately 30 feet
and maximum speed of 720 Kbps
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Institute of Electrical and Electronics
Engineers (IEEE) Protocols
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Ethernet Cabling Types and Speeds
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IPv6 Changes
• Newer versions of TCP and UDP
• CHECKv4.EXE
– Utility provided by Microsoft to help developers
find code that must be modified to work with IPv6
• Neighbor Solicitation multicast packet
– Used to find the MAC address of an IPv6 host
– Replaces ARP
• Multicast Listener Discovery (MLD)
– Replaces the functionality of IGMP
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Summary
• TCP/IP model
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Application layer
Transport layer
Internet layer
Network interface layer
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Summary (Continued)
• Application layer protocols
– HTTP: the most common protocol in use
– FTP: used for transferring files across the Internet
– Telnet: used to remotely connect to UNIX and
Linux systems
– SMTP: used to send and receive e-mail
messages
– POP3: most common protocol used for reading email messages
– IMAP4: used for reading e-mail messages
Transport layer protocols
– TCP: connection-oriented and reliable
– UDP: connectionless and unreliable
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Summary (Continued)
• Internet layer protocols
– Responsible tasks related to logical addressing
– Includes IP, RIP, OSPF, ICMP, IGMP, and ARP
• Ethernet
– The most common network interface layer
protocol in use
• Wireless LANs
– One of the fastest growing network types
• IPv6 changes
– New versions of TCP and UDP
– Discontinued use of ARP
– Replacement of IGMP with Multicast Listener
Discovery
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