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Internet Addressing and Delivery Basics
What is an IP Address?
 | To communicate on the Internet each computer (also known as a host or a node) must have
a unique identifier called an IP (Internet Protocol) address. |
| An IP address is:
 | a 32 bit binary number |
| represented as 4 fields |
| each representing 8 bit numbers in the range 0 to 255 (sometimes called octets) |
| separated by decimal points |
| Example: 128.118.5.40 or 146.186.110.69 |
|
Address Classes
| The first few bits of each IP address indicate which of the address class formats it is
using. |
| Class A addresses are for large networks with many devices.
| 126 separate networks |
|
| 0 |
Network (7 bits) |
Local address (24 bits) |
|
|
| Class B addresses are for medium-sized networks.
| 128-191 |
|
| 10 |
Network (14 bits) |
Local address (16 bits) |
|
|
| Class C addresses are for small networks (fewer than 256 devices).
| 192-223 |
|
| 110 |
Network (21 bits) |
Local address (8 bits) |
|
|
| Class D addresses are multicast addresses.
| 224-225 |
|
| 1110 |
Multicast address (28 bits) |
|
|
| For Class A IP addresses, the numbers would represent
"network.local.local.local"; for a Class C IP address, they would represent
"network.network.network.local". |
IPv6 or IPng
| Evolutionary set of improvements to the current IP Version 4. |
| Solves several major problems - scalability, flexibility, and new functionality. |
| Scalability - IP addresses are lengthened from 32 bits to 128 bits.
| Thus increasing the number of available address to 3.4 x 1038 |
| 1077:0:0:0:8:759:154C:413A |
|
| Backwardly Compatible - designed to interoperate with IPv4 |
| Routing Capabilities
| unicast (one host to one other host) |
| anycast (one host to the nearest of multiple hosts) |
| multicast (one host to multiple hosts). |
|
| RFC
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| Reference
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TCP/IP and the OSI Model
| The OSI Reference Model is based on a proposal developed by the International Standards
Organization (ISO). The model is called ISO OSI (Open Systems Interconnect) Reference
Model because it deals with connecting open systems - that is, systems that are open for
communication with other systems. |
| The DoD Model is also very useful methodology to view the network communications. |
DoD Model Layers
| The Network Access Layer
| Responsible for delivering data over the particular hardware media in use. |
| Different protocols are selected from this layer, depending on the type of physical
network. |
|
| The Internet Layer
| Responsible for delivering data across a series of different physical networks that
interconnect a source and destination machine. |
| Routing protocols are most closely associated with this layer, as is the IP Protocol,
the Internet's fundamental protocol. |
|
| The Host-to-Host (Transport) Layer
| Handles connection rendezvous, flow control, retransmission of lost data, and other
generic data flow management. |
| The mutually exclusive TCP and UDP protocols are this layer's most important members. |
|
| The Process (Application) Layer
| Contains protocols that implement user-level functions, such as mail delivery, file
transfer and remote login. |
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Layers and Protocol Association
| Layer |
Protocols |
Process/Application
| Addresses the ability of one application to
communicate with another, regardless of hardware platform, operating system and other host
features |
| Defines protocols for node-to-node application communication |
| Controls end-user interface specifications |
|
FTP
DNS
HTTP
LPD
NFS
TFTP
SMTP
SNMP
Telnet
X window |
Host To Host/Transport
| Defines protocols for setting up the level of transmission service for applications |
| Creates reliable end-to-end communications |
| Ensures error-free delivery of data |
| Handles packet sequencing and maintains data integrity |
|
TCP
UDP |
Internet
| Designates protocols for the logical transmission of packets over the entire network |
| Addresses hosts by giving them an IP address and handles the routing of packets among
multiple networks |
|
ARP
BootP
ICMP
IP
RARP |
Network Access
| Monitors the data exchange between the host and the network |
| Oversees hardware addressing and defines protocols for the physical transmission of data
|
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Ethernet
Fast Ethernet
FDDI
Token Ring |
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