Title: Protocols and the TCP/IP Suite Chapter-4
1Protocols and the TCP/IP SuiteChapter-4
2Objectives
- TCP/IP Protocol Suite
- Transmission Control Protocol/Internet Protocol
- Internet addresses
- IPv4, IPv6
- Obtaining an IP address
- How network devices obtain IP addresses
3History and Future of TCP/IP
- The U.S. Department of Defense (DoD) created the
TCP/IP reference model because it wanted a
network that could survive any conditions. - Some of the layers in the TCP/IP model have the
same name as layers in the OSI model.
4Application Layer
- Handles high-level protocols, issues of
representation, encoding, and dialog control. - The TCP/IP protocol suite combines all
application related issues into one layer and
ensures this data is properly packaged before
passing it on to the next layer.
5Application Layer Examples
- Telnet Provides the capability to remotely
access another computer - File Transfer Protocol (FTP) Download or upload
files - Hypertext Transfer Protocol (HTTP) Works with
the World Wide Web
6Application Layer Examples
7Transport Layer
- Five basic services
- Segmenting upper-layer application data
- Establishing end-to-end operations
- Sending segments from one end host to another end
host - Ensuring data reliability
- Providing flow control
8Transport Layer Protocols
9Internet Layer
- The purpose of the Internet layer is to send
packets from a network node and have them arrive
at the destination node independent of the path
taken. - Internet layer protocols
- Internet Protocol (IP)
- Internet Control Message Protocol (ICMP)
- Address Resolution Protocol (ARP)
- Reverse Address Resolution Protocol (RARP)
10Internet Layer
11Network Access Layer
- The network access layer is concerned with all of
the issues that an IP packet requires to actually
make a physical link to the network media. - It includes the LAN and WAN technology details,
and all the details contained in the OSI physical
and data link layers.
12Comparing the OSI Model and TCP/IP Model
13Similarities of the OSI and TCP/IP models
- Both have layers.
- Both have application layers, though they include
very different services. - Both have comparable transport and network
layers. - Packet-switched, not circuit-switched, technology
is assumed. - Networking professionals need to know both
models.
14Differences of the OSI and TCP/IP models
- TCP/IP combines the presentation and session
layer into its application layer. - TCP/IP combines the OSI data link and physical
layers into one layer. - TCP/IP appears simpler because it has fewer
layers. - TCP/IP transport layer using UDP does not always
guarantee reliable delivery of packets as the
transport layer in the OSI model does.
15Internet Architecture
- Two computers, anywhere in the world, following
certain hardware, software, protocol
specifications, can communicate, reliably even
when not directly connected. - LANs are no longer scalable beyond a certain
number of stations or geographic separation.
16Internet Addresses
17IP Addressing
- An IP address is a 32-bit sequence of 1s and 0s.
- To make the IP address easier to use, the address
is usually written as four decimal numbers
separated by periods. - This way of writing the address is called the
dotted decimal format.
18IP Address as a 32-Bit Binary Number
19Binary and Decimal Conversion
20Decimal and Binary Conversion
21IP Address Classes
22IP Address Classes
23IP Addresses as Decimal Numbers
24Hosts for Classes of IP Addresses
Class A (24 bits for hosts) 224 - 2 16,777,214
maximum hosts Class B (16 bits for hosts) 216 -
2 65,534 maximum hosts Class C (8 bits for
hosts) 28 - 2 254 maximum hosts Subtracting
the network and broadcast reserved address
25IP Addresses as Decimal Numbers
26Network IDs and Broadcast Addresses
An IP address such as 176.10.0.0 that has all
binary 0s in the host bit positions is reserved
for the network address.
An IP address such as 176.10.255.255 that has all
binary 1s in the host bit positions is reserved
for the broadcast address.
27Private Addresses
28Reserved Address Space
- Network ID
- Broadcast address
- Hosts for classes of IP addresses
29Basics of Subnetting
- Classical IP addressing
- Subnetworks
- Subnet mask
- Boolean operations AND, OR, and NOT
- Performing the AND function
30Subnetworks
- To create a subnet address, a network
administrator borrows bits from the original host
portion and designates them as the subnet field.
31Subnetworks
32Subnet Mask
- Determines which part of an IP address is the
network field and which part is the host field - Follow these steps to determine the subnet mask
- 1. Express the subnetwork IP address in binary
form. - 2. Replace the network and subnet portion of the
address with all 1s. - 3. Replace the host portion of the address with
all 0s. - 4. Convert the binary expression back to
dotted-decimal notation.
33Subnet Mask
Subnet mask in decimal 255.255.240.0
34Boolean Operations AND, OR, and NOT
- AND is like multiplication.
- OR is like addition.
- NOT changes 1 to 0, and 0 to 1.
35Performing the AND Function
36Range of Bits Needed to Create Subnets
37Subnet Addresses
38Decimal Equivalents of 8-Bit Patterns
39Creating a Subnet
- Determining subnet mask size
- Computing subnet mask and IP address
- Computing hosts per subnetwork
- Boolean AND operation
- IP configuration on a network diagram
- Host and subnet schemes
- Private addresses
40Determining Subnet Mask Size
Class B address with 8 bits borrowed for the
subnet 130.5.2.144 (8 bits borrowed for
subnetting) routes to subnet 130.5.2.0 rather
than just to network 130.5.0.0.
41Determining Subnet Mask Size
Class C address 197.15.22.131 with a subnet mask
of 255.255.255.224 (3 bits borrowed)
11000101 00001111 00010110 100 00011
Network Field Network Field Network Field SN Host Field
The address 197.15.22.131 would be on the subnet
197.15.22.128.
42Subnetting Example with AND Operation
43Determine the Number of Valid Subnets
- How many valid subnets exist on 10.0.0.0/12 ?
- How many valid subnets exist on 10.0.0.0
255.240.0.0 ?
44Determining Number of Valid Hosts
- How many valid hosts exist on 150.10.0.0/20 ?
- How many valid hosts exist on 150.10.0.0
255.255.240.0 ?
45Determining the Subnet Number of A given IP
address
- What subnet is the address 200.17.49.200/23 a
member of? - On what subnet can the address 200.17.49.200/23
be found?
46Determining Broadcast Address and Valid IP
address Ranges
- What is the range of valid IP addresses for the
subnet 210.210.210.0/25? - What is the broadcast address for the subnet
210.210.210.1/25 ? - Which of the following IP addresses are found on
the same subnet as the IP address
210.210.210.1/25?
47IP Configuration on a Network Diagram
The router connects subnetworks and networks.
48Host Subnet Schemes
The number of lost IP addresses with a Class C
network depends on the number of bits borrowed
for subnetting.
49IPv4 versus IPv6
- IP version 6 (IPv6) has been defined and
developed. - IPv6 uses 128 bits rather than the 32 bits
currently used in IPv4. - IPv6 uses hexadecimal numbers to represent the
128 bits.
IPv4
50Obtaining an IP Address
51Obtaining an IP Address
- Static addressing
- Each individual device must be configured with an
IP address. - Dynamic addressing
- Reverse Address Resolution Protocol (RARP)
- Bootstrap Protocol (BOOTP)
- Dynamic Host Configuration Protocol (DHCP)
- DHCP initialization sequence
- Function of the Address Resolution Protocol
- ARP operation within a subnet
52Static Assignment of IP Addresses
- Each individual device must be configured with an
IP address. - Each operating system has its own way of
configuring TCP/IP - Requires records to be maintained of address
assignments- emphasizes good record keeping - Some operating systems designed to check for
duplicate address allocation
53Reverse Address Resolution Protocol (RARP)
- Binds MAC addresses to IP addresses
- Devices using RARP require that a RARP
- server be present on the network to answer RARP
requests - If a device knows its MAC address but is unable
to locate IP address in the ARP table, it
initiates the process called RARP
54Reverse Address Resolution Protocol (RARP)
The source initiates a RARP request, which helps
it detect its own IP address.
55BOOTP IP Assignment
- The Bootstrap Protocol (BOOTP) operates in a
client/server environment and only requires a
single packet exchange to obtain IP information. - BOOTP packets can include the IP address, as well
as the address of a router, the address of a
server, and vendor-specific information. - Does not provide dynamic address allocation
- Administrator must add hosts and maintain BOOTP
database - One-to-One relationship exists between IP
addresses and the number of hosts
56BOOTP IP Assignment
- A client uses BOOTP to send a broadcast IP
- A BOOTP server receives the broadcast and then
sends back a broadcast - The client receives a frame and checks the MAC
address. If it finds its MAC address in the
destination field and a broadcast in the IP
destination field, it takes and stores the IP
address other information supplied in the BOOTP
reply message
57Dynamic Host Configuration Protocol
- Successor to BOOTP
- Allows a hosts to obtain IP addresses dynamically
- Host to obtain an IP address using a defined
range of IP addresses on a DHCP server. - As hosts come online, contact the DHCP server,
and request an address. - Entire TCP/IP configuration can be obtained in
one message
58DHCP Initialization Sequence
Client collects DHCP offer responses from the
server.
59Address Resolution Protocol (ARP)
- For devices to communicate, the sending device
needs - Destination MAC address
- Destination IP address
- If a device knows the destination IP address, to
communicate it needs the destination MAC address - To obtain the MAC address the device invokes ARP
60ARP
t
ARP enables a computer to find the MAC
address of the computer that is associated with
an IP address.
61ARP Operation Within a Subnet
All devices on the network receive the packet and
pass to network layer only one device responds
with an ARP reply.
62ARP Process
63Advanced ARP Concepts
- Default gateway
- Proxy ARP
64Default Gateway
A default gateway is the IP address of the
interface on the router that connects to the
network segment on which the source host is
located.
65How ARP Sends Data to Remote Networks
66Proxy ARP