Transcript 2: TCP/IP Architecture

70-293: MCSE Guide to
Planning a Microsoft Windows
Server 2003 Network,
Enhanced
Chapter 2:
TCP/IP Architecture
Objectives
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Understand TCP/IP addressing
Describe the overall architecture of TCP/IP
Describe Application layer protocols
Discuss Transport layer protocols
Understand the role of various Internet layer
protocols, including IP,ICMP, and ARP
• Understand Network Interface layer protocols
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Introduction To TCP/IP
• Transmission Control Protocol/Internet Protocol
(TCP/IP)
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Most commonly used network protocol suite today
Wide vendor support
Open protocol
Provides access to Internet services
• Windows Server 2003
• Can use several protocols
• Many of its main features require the use of TCP/IP
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Activity 2-1:
Repairing a Network Connection
• The purpose of this activity is to repair a connection
that has a corrupt TCP/IP configuration
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IP Addresses
• An IP address, like a mailing address for a house, is
unique
• An IP addresses has four numbers, each called an
octet, that are separated by periods
• Each octet in an IP address represents eight bits of
information
• A full IP address of four octets is 32 bits long
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IP Addresses (continued)
• An example of an IP address is 192.168.5.66
• An IP address is composed of two parts: the network
ID and the host ID
• The network ID represents the network on which the
computer is located
• The host ID represents the individual computer on a
network
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Subnet Masks
• A subnet mask defines which part of its IP address is
the network ID and which part is the host ID
• Subnet masks are composed of four octets just like an
IP address
• Wherever there is a 255 in the subnet mask, that octet
is part of the network ID
• Wherever there is a 0 in the subnet mask, that octet is
part of the host ID
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Subnet Masks (continued)
• A computer uses its subnet mask to determine
• Which network it is on
• Whether other computers are on the same network or a
different network
• If two computers on the same network are
communicating, then they can deliver packets directly
to each other
• If two computers are on different networks, they must
use a router to communicate
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Subnet Masks (continued)
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Default Gateway
• Default gateway is another term for router
• If a computer does not know how to deliver a packet,
it gives the packet to the default gateway to deliver
• Routers can distinguish multiple networks and how to
move packets between them
• Routers can also figure out the best path to use to
move a packet between different networks
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Activity 2-2:
Viewing IP Address
Configuration
• The purpose of this activity is to view the current IP
address settings on a server
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IP Address Classes
• IP addresses are divided into classes: A-E
• IP address classes can be identified by the first octet
• Class A addresses use eight bits for the network ID
and 24 bits for the host ID
• Class A networks are only assigned to very large
companies and Internet providers
• Class B addresses use 16 bits for the network ID and
16 bits for the host ID
• Class B networks are assigned to many larger
organizations, such as governments, universities, and
companies with several thousand users
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IP Address Classes (continued)
• Class C addresses use 24 bits for the network ID and
eight bits for the host ID
• Class C networks have a relatively small number of
hosts and are suited only to smaller organizations
• Class D addresses are not divided into networks and
they cannot be assigned to computers as IP addresses
• Class D addresses are used for multicasting
• Class E addresses are considered experimental and
are not used
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IP Address Classes (continued)
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Classless Inter-domain Routing
• Classless interdomain routing (CIDR) makes Internet
routing and assignment of IP addresses more efficient
• CIDR does not use the default subnet masks for
routing. Instead, the subnet mask must be defined for
each network
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Classless Inter-domain Routing
(continued)
• Definable subnet mask is more flexible and efficient
• CIDR reduces the number of routing table entries that
Internet backbone routers must hold
• A single routing table entry can replace hundreds or
thousands of entries for Class C networks
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Reserved Addresses
• Reserved addresses are a number of IP addresses and
IP networks that are reserved for special purposes and
either cannot be assigned to hosts or cannot be used
on the Internet
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DNS
• Domain Name System (DNS) is used to:
• resolve host names to IP addresses
• find domain controllers
• find e-mail servers
• DNS is essential for Active Directory to work
properly
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WINS
• Windows Internet Naming Service (WINS) is used to:
• resolve NetBIOS names to IP addresses
• stores information about services such as domain
controllers
• Provide backward compatibility with Windows NT and
Windows 9x
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DHCP
• Dynamic Host Configuration Protocol (DHCP) is an
automated mechanism to assign IP addresses to
clients
• Automating this process avoids the problem of
records being entered incorrectly
• If a change needs to be made for the IP addressing
information, you can simply change the information
in the DHCP server
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Activity 2-3:
Using IPCONFIG to View IP
Configuration
• The purpose of this activity is to view the current IP
settings using the IPCONFIG utility
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Activity 2-4:
Configuring an Alternative IP
Configuration
• The purpose of this activity is to configure alternative
IP address information to be used when a DHCP
server is unavailable
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TCP/IP Architecture Overview
• The TCP/IP model can be broken down into four
layers:
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Application
Transport
Internet
Network Interface
• Application layer provides access to network
resources
• It defines rules, commands, and procedures for client
to talk to a service running on a server
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TCP/IP Architecture Overview
(continued)
• Transport layer is responsible for preparing data to be
transported across the network
• Internet layer is responsible for logical addressing
and routing
• Network Interface layer consists of the network card
driver and the network card itself
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Application Layer Protocols
• There are many Application layer protocols, each of
which is associated with a client application and
service
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HTTP
FTP
TELNET
SMTP
POP3
IMAP4
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HTTP
• Hypertext Transfer Protocol (HTTP) is the most
common protocol used on the Internet today
• HTTP defines the commands that Web browsers can
send and how Web servers are capable of responding
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FTP
• File Transfer Protocol (FTP) is file-sharing protocol
• FTP is implemented in stand-alone FTP clients as
well as in Web browsers
• It is safe to say that most FTP users today are using
Web browsers
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Activity 2-5:
Using FTP to Download a File
• The purpose of this activity is to use FTP to
download a utility
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TELNET
• Telnet is a terminal emulation protocol that is
primarily used to connect remotely to UNIX and
Linux Systems
• The Telnet protocol specifies how a telnet server and
telnet client communicate
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SMTP
• Simple Mail Transfer Protocol (SMTP) is used to
send and receive e-mail messages between e-mail
servers that are communicating
• It is used by e-mail client software, such as Outlook
Express, to send messages to the server
• SMTP is never used to retrieve e-mail from a server
when you are reading it
• Other protocols control the reading of e-mail
messages
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Activity 2-6: Using Telnet to
Verify SMTP
• The purpose of this activity is to use Telnet to verify
the functionality of an SMTP server
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POP3
• Post Office Protocol version 3 (POP3) is the most
common protocol used for reading e-mail messages
• This protocol has commands to download messages
and delete messages from the mail server
• POP3 does not support sending messages
• POP3 supports only a single inbox and does not
support multiple folders for storage on the server
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IMAP4
• Internet Message Access Protocol version 4 (IMAP4)
is another common protocol used to read e-mail
messages
• IMAP4 can download message headers only and
allow you to choose which messages to download
• IMAP4 allows for multiple folders on the server side
to store messages
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Transport Layer Protocols
• Transport layer protocols are responsible for getting
data ready to move across the network
• The most common task performed by Transport layer
protocols is breaking entire messages down into
packets
• Transport layer protocols use port numbers
• Each Transport layer protocol has its own set of ports
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Transport Layer Protocols
(continued)
• When a packet is addressed to a particular port, the
Transport layer protocol knows to which service to
deliver the packet
• The combination of an IP address and port number is
referred to as a socket
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Transport Layer Protocols
(continued)
• A port number is like an apartment number for the
delivery of mail
• Network ID of the IP address ensures packet is
delivered to the correct street (network)
• Host ID ensures packet is delivered to the correct
building (host)
• Transport layer protocol and port number ensure
packet is delivered to the proper apartment (service)
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Activity 2-7:
Using Port Numbers
• The purpose of this activity is to Connect to resources
using TCP and UDP port numbers
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TCP
• Transmission Control Protocol (TCP) is the most
commonly used Transport layer protocol
• TCP is connection-oriented and reliable
• Connection-oriented means that TCP creates and
verifies a connection with a remote host before
sending information
• Verifies that the remote host exists and is willing to
communicate before starting the conversation
• TCP is the Transport layer protocol used for most
Internet services
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Activity 2-8:
Installing Network Monitor
• The purpose of this activity is to install Network
Monitor to enable packet capturing
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Activity 2-9:
Viewing a TCP Connection in
Network Monitor
• The purpose of this activity is to capture and view
TCP connection packets in Network Monitor
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UDP
• User Datagram Protocol (UDP)
• Not as commonly used as TCP
• Used for different services
• Connectionless and unreliable
• UDP is the appropriate if
• Unconcerned about missing packets
• Want to implement reliability in a special way
• Streaming audio and video are in this category
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Activity 2-10:
Capturing UDP Packets in
Network Monitor
• The purpose of this activity is to capture and view
UDP packets in Network Monitor
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TCP versus UDP
• TCP is connection-oriented and reliable
• Like registered mail
• UDP is connectionless and unreliable
• Like sending a message split on several postcards and
assuming that the receiver will be able to put the message
together
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Internet Layer Protocols
• Internet layer protocols are responsible for all tasks
related to logical addressing
• An IP address is a logical address
• Any protocol that is aware of other networks exists at
this layer
• Each Internet layer protocol is very specialized
• They include: IP, RIP and OSPF, ICMP, IGMP, and
ARP
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IP
• Internet Protocol (IP) is responsible for the logical
addressing of each packet created by the Transport
layer
• As each packet is built, IP adds the source and
destination IP address to the packet
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RIP and OSPF
• Routing Information Protocol (RIP) and Open
Shortest Path First (OSPF) are both routing protocols
• They are responsible for defining how paths are
chosen through the internetwork from one computer
to another
• They also define how routers can share information
about the networks of which they are aware
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ICMP
• Internet Control Messaging Protocol (ICMP) is used
to send IP error and control messages between routers
and hosts
• The most common use of ICMP is the ping utility
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Activity 2-11:
Testing Host Functionality
• The purpose of this activity is to test the functionality
of a host using the ping command
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Activity 2-12: Viewing TTL
• The purpose of this activity is to view the TTL of a
ping packet
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IGMP
• Internet Group Management Protocol (IGMP) is 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
• The use of IGMP allows multicast packets to be
distributed only to routers that have interested hosts
connected
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ARP
• Address Resolution Protocol (ARP) is used to convert
logical IP addresses to physical MAC addresses
• This is an essential part of the packet delivery process
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Activity 2-13:
Viewing the ARP Cache
• The purpose of this activity is to View the contents of
the ARP cache
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Network Interface Layer
Protocols
• Most of the common Network Interface layer
protocols are defined by the Institute of Electrical
and Electronics Engineers (IEEE)
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Summary
• Windows Server 2003 uses TCP/IP as its primary
networking protocol
• An IP address has a network ID and a host ID
• A subnet mask defines which part of the IP address is
the network ID and which is host ID
• A default gateway is required to deliver packets of
information from one network to another
• The TCP/IP model is composed of four layers:
Application, Transport, Internet, Network Interface
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Summary (continued)
• HTTP is the most common protocol used on the
Internet today
• The two Transport layer protocols are TCP and UDP
• The two Transport layer protocols are TCP and UDP
• Internet layer protocols are responsible for all tasks
related to logical addressing and are all very
specialized
• Internet layer protocols include IP, RIP, OSPF, ICMP,
IGMP, and ARP
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