Title: Chapter Three
1Chapter Three
2Agenda
- Attendance, and Ch.2 Quiz questions
- TCP/IP Model
- IP Header (Using Ethereal to analyze the IP
header) - TCP Header (using Ethereal to analyze the TCP
Header) - Address Resolution Protocol Lab
3Introduction to Protocols
- Protocol
- Rules network uses to transfer data
- Protocols that can span more than one LAN segment
are routable - Multiprotocol network
- Network using more than one protocol
4TCP/IP
OSI Model
TCP/IP
- Transmission Control Protocol/Internet Protocol
(TCP/IP) - Suite of small, specialized protocols called
subprotocols
5TCP/IP model
- File Transfer Protocol (FTP)
- Hypertext Transfer Protocol (HTTP)
- Simple Mail Transfer Protocol (SMTP)
- Domain Name System (DNS)
- Trivial File Transfer Protocol (TFTP)
- The common transport layer
- protocols include
- Transport Control Protocol (TCP)
- User Datagram Protocol (UDP)
- The primary protocol of the
- Internet layer is
- Internet Protocol (IP)
6TCP/IP model
7TCP/IP Compared to theOSI Model
- Application layer roughly corresponds to Session,
Application, and Presentation layers of OSI Model - Transport layer roughly corresponds to Transport
and session layers of OSI Model - Internet layer is equivalent to Network layer of
OSI Model - Network Interface layer roughly corresponds to
Data Link and Physical layers of OSI Model
8The TCP/IP Core Protocols
- Certain subprotocols of TCP/IP suite
- Operate in Transport or Network layers of OSI
Model - Provide basic services to protocols in other
layers of TCP/IP - TCP and IP are most significant core protocols in
TCP/IP suite
9Internet Protocol (IP)
- Provides information about how and where data
should be delivered - Subprotocol that enables TCP/IP to internetwork
- To internetwork is to traverse more than one LAN
segment and more than one type of network through
a router - In an internetwork, the individual networks that
are joined together are called subnetworks
10Internet Protocol (IP)
- IP datagram
- IP portion of TCP/IP frame that acts as an
envelope for data - Contains information necessary for routers to
transfer data between subnets
11IP header format
12IP header format Version
- 4 bits.
- Indicates the version of IP currently used.
- IPv4 0100
- IPv6 0110
13IP header format Header length
- 4 bits.
- IP header length Indicates the datagram header
length in 32 bit words (4 bits), and thus points
to the beginning of the data.
14IP header format Service type
- 8 bits.
- Specifies the level of importance that has been
assigned by a particular upper-layer protocol. - Precedence.
- Reliability.
- Speed.
15IP header format Total length
- 16 bits.
- Specifies the length of the entire IP packet,
including data and header, in bytes.
16IP header format Identification
- 16 bits.
- Identification contains an integer that
identifies the current datagram. - Assigned by the sender to aid in assembling the
fragments of a datagram.
17IP header format Flags
- 3 bits.
- The second bit specifying whether the packet can
be fragmented . - The last bit specifying whether the packet is the
last fragment in a series of fragmented packets.
18IP header format Fragment offset
- 13 bits.
- The field that is used to help piece together
datagram fragments. - The fragment offset is measured in units of 8
octets (64 bits). - The first fragment has offset zero.
19IP header format Time to Live
- 8 bits.
- Time-to-Live maintains a counter that gradually
decreases to zero, at which point the datagram is
discarded, keeping the packets from looping
endlessly.
20IP header format Protocol
- 8 bits.
- Indicates which upper-layer protocol receives
incoming packets after IP processing has been
completed - 06 TCP
- 17 UDP
21IP header format Header checksum
- 16 bits.
- A checksum on the header only, helps ensure IP
header integrity.
22IP header format Addresses
- 32 bits each.
- Source IP Address
- Destination IP Address
23IP header format Options
- Variable length.
- Allows IP to support various options, such as
security, route, error report ...
24IP header format Padding
- The header padding is used to ensure that the
internet header ends on a 32 bit boundary.
25Ethereal Lab (Analyzing the IP Header)
- Use Ethereal to capture some frames. Open one of
the frames and look at the IP header. Based on
what you see, try to answer the following - What is the IP version?
- What is the IP header length?
- What is the type of Service?
- What is the time to live?
- What is the protocol?
- What is the source IP address?
- What is the destination IP address?
26Internet Protocol (IP)
- IP is an unreliable, connectionless protocol,
which means it does not guarantee delivery of
data - Connectionless
- Allows protocol to service a request without
requesting verified session and without
guaranteeing delivery of data
27Transport Control Protocol (TCP)
- TCP
- Provides reliable data delivery services
- Connection-oriented subprotocol
- Requires establishment of connection between
communicating nodes before protocol will transmit
data - TCP segment
- Holds TCP data fields
- Becomes encapsulated by IP datagram
28Transport Control Protocol (TCP)
- Port
- Address on host where application makes itself
available to incoming data
29Ethereal Lab (Analyzing the TCP Header)
- Use Ethereal to capture some frames. Open one of
the frames and look at the TCP header. Based on
what you see, try to answer the following - What is the source Port?
- What is the destination Port?
- What is the sequence Number?
- What Is the Acknowledgement Number?
- What is the header Length?
30Additional Core Protocols of the TCP/IP Suite
- User Datagram Protocol (UDP)
- Connectionless transport service
- Internet Control Message Protocol (ICMP)
- Notifies sender of an error in transmission
process and that packets were not delivered - Address Resolution Protocol (ARP)
- Obtains MAC address of host or node
- Creates local database mapping MAC address to
hosts IP address
31 32Agenda
- Attendance and questions about last weeks
material. - TCP/IP Application Layers
- FTP Lab
- Telnet Lab
- Break
- Binary and hexadecimal conversion
33TCP/IP Application Layer Protocols
- Telnet
- Used to log on to remote hosts using TCP/IP
protocol suite - File Transfer Protocol (FTP)
- Used to send and receive files via TCP/IP
- Simple Mail Transfer Protocol (SMTP)
- Responsible for moving messages from one e-mail
server to another, using the Internet and other
TCP/IP-based networks - Simple Network Management Protocol (SNMP)
- Manages devices on a TCP/IP network
34Labs
35Addressing in TCP/IP
- IP Address
- Logical address used in TCP/IP networking
- Unique 32-bit number
- Divided into four groups of octets (8-bit bytes)
that are separated by periods - IP addresses are assigned and used according to
very specific parameters
36Addressing in TCP/IP
- Though 8 bits have 256 possible combinations,
only the numbers 1 through 254 are used to
identify networks and hosts - Number 255 is reserved for broadcasts
- Broadcast are transmissions to all stations on a
network
37Addressing in TCP/IP
- Loopback address
- IP address reserved for communicating from a node
to itself - Value of the loopback address is always 127.0.0.1
- Internet Corporation for Assigned Names and
Numbers (ICANN) - Non-profit organization currently designated by
U.S. government to maintain and assign IP
addresses
38Addressing in TCP/IP
- Firewall
- Specialized device (typically a router)
- Selectively filters or blocks traffic between
networks - May be strictly hardware-based or may involve a
combination of hardware and software - Host
- Computer connected to a network using the TCP/IP
protocol
39Addressing in TCP/IP
- In IP address 131.127.3.22, to convert the first
octet (131) to a binary number - On Windows 2000, click Start, point to Programs,
point to Accessories, then click Calculator - Click View, then click Scientific (make sure Dec
option button is selected) - Type 131, then click Bin option button
- The binary equivalent of number 131, 10000011,
appears in the display window
40Addressing in TCP/IP
- Static IP address
- IP address manually assigned to a device
- Dynamic Host Configuration Protocol (DHCP)
- Application layer protocol
- Manages dynamic distribution of IP addresses on a
network
41Viewing Current IP Information
42Viewing Current IP Information
43Addresses and Names
- In addition to using IP addresses, TCP/IP
networks use names for networks and hosts - Each host requires a host name
- Each network requires a network name, also called
a domain name - Together, host name and domain name constitute
the fully qualified domain name (FQDN)
44NetBIOS and NetBEUI
- Network Basic Input Output System (NetBIOS)
- Originally designed by IBM to provide Transport
and Session layer services - Adopted by Microsoft as its foundation protocol
- Microsoft added Application layer component
called NetBEUI
45NetBIOS and NetBEUI
- NetBIOS Enhanced User Interface
- Fast and efficient protocol
- Consumes few network resources
- Provides excellent error correction
- Requires little configuration
- Can handle only 254 connections
- Does not allow for good security
46NetBIOS Addressing
47Installing Protocols
- After installing protocols, they must be binded
to NICs and services they run on or with - Binding
- Process of assigning one network component to
work with another
48Chapter Summary
- Protocols define standards for communication
between nodes on a network - Protocols vary in speed, transmission efficiency,
utilization of resources, ease of setup,
compatibility, and ability to travel between one
LAN segments - TCP/IP is the most popular network protocol
49Chapter Summary
- TCP/IP suite of protocols can be divided into
four layers roughly corresponding to seven layers
of OSI Model - Operating in Transport or Network layers of OSI
Model, TCP/IP core protocols provide
communications between hosts on a network - Each IP address is a unique 32-bit number,
divided into four groups of octets separated by
periods
50Chapter Summary
- Every host on a network must have a unique number
- Internetworking Packet Exchange/Sequenced Packet
Exchange (IPX/SPX) is a protocol originally
developed by Xerox then modified and adopted by
Novell in the 1980s for its NetWare network
operating system - Core protocols of IPX/SPX provide services at
Transport and Network layers of OSI Model
51Chapter Summary
- Addresses on an IPX/SPX network are called IPX
addresses - Network Basic Input Output System (NetBIOS) was
originally developed by IBM to provide Transport
and Session layer services - Microsoft adopted NetBIOS as its foundation
protocol, then added an Application layer
component called NetBIOS Enhanced User Interface
(NetBEUI)
52Chapter Summary
- To transmit data between network nodes, NetBIOS
needs to know how to reach each workstation - Each workstation must have a NetBIOS name
- AppleTalk is the the protocol suite used to
interconnect Macintosh computers - An AppleTalk network is separated into logical
groups of computers called AppleTalk zones
53Chapter Summary
- Though Apple has improved AppleTalks ability to
use different network models and span network
segments, it remains unsuited to large LANs or
WANs - In addition to zone names, AppleTalk uses node
IDs and network numbers to identify computers on
a network - Though some protocols (such as NetBIOS) require
no configuration after installation, others (such
as TCP/IP) do require configuration
54Next Week
- Make sure that you have taken chapter 3 Quiz
online - Make sure that you have read chapter 11
- Download packet tracer from my web site and
install it at home. Try to read the tutorial to
gain some understanding on how it works. You
will use this program in your project