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CCNA

OSI TCP/IP

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OSI Model TCP/IP Model
It is developed by ISO (International Standard Organization) It is developed by ARPANET (Advanced Research Project Agency Network).
OSI model provides a clear distinction between interfaces, services, and protocols. TCP/IP doesn't have any clear distinguishing points between services, interfaces, and protocols.
OSI refers to Open Systems Interconnection. TCP refers to Transmission Control Protocol.
OSI uses the network layer to define routing standards and protocols. TCP/IP uses only the Internet layer.
OSI follows a vertical approach. TCP/IP follows a horizontal approach.
OSI layers have seven layers. TCP/IP has four layers.
In the OSI model, the transport layer is only connection-oriented. A layer of the TCP/IP model is both connection-oriented and connectionless.
In the OSI model, the data link layer and physical are separate layers. In TCP, physical and data link are both combined as a single host-to-network layer.
Session and presentation layers are a part of the OSI model. There is no session and presentation layer in the TCP model.
It is defined after the advent of the Internet. It is defined before the advent of the internet.
The minimum size of the OSI header is 5 bytes. The minimum header size is 20 bytes.

IP

What is IP

Internet Protocol a lable assigned to nodes that commected to a network that use internet protocol for communication with other nodes.

IPV4

Internet Protocol Version 4,the fourth version of the internet protocol. It is one of the standards based networking methods in the internet networks.

Addressing

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Class

Class A Class B Class C Class D Class E
IP Range 1.0.0.0~127.255.255.255 128.0.0.0~191.255.255.255 192.0.0.0~223.255.255.255 224.0.0.0~239.255.255.255 240.0.0.0~255.255.255.255
Available IP Range 1.0.0.1~127.255.255.254 128.0.0.1~191.255.255.254 192.0.0.1~223.255.255.254
Can be assigned to the host YES YES YES NO NO
IP amount 126 (27-2) 16384 (214) 2097152 (221)
Host amount 16777214 (224-2) 65534 (216-2) 254 (28-2)
applicable Large Network with a Large amount of hosts Network with medium sized hosts Small local area network Use by the Internet Architecture Board (IAB) Multicast address only of research,Internet experimet and development

Special Use Address

Address Book Address Reange Number Of Addresses Scope Description
0.0.0.0/8 0.0.0.0–0.255.255.255 16777216 Software Current network (only valid as source address).
10.0.0.0/8 10.0.0.0–10.255.255.255 16777216 Private network Used for local communications within a private network.
100.64.0.0/10 100.64.0.0–100.127.255.255 4194304 Private network Shared address space for communications between a service provider and its subscribers when using a carrier-grade NAT.
127.0.0.0/8 127.0.0.0–127.255.255.255 16777216 Host Used for loopback addresses to the local host.
169.254.0.0/16 169.254.0.0–169.254.255.255 65536 Subnet Used for link-local addresses between two hosts on a single link when no IP address is otherwise specified, such as would have normally been retrieved from a DHCP server.
172.16.0.0/12 172.16.0.0–172.31.255.255 1048576 Private network Used for local communications within a private network.
192.0.0.0/24 192.0.0.0–192.0.0.255 256 Private network IETF Protocol Assignments.
192.0.2.0/24 192.0.2.0–192.0.2.255 256 Documentation Assigned as TEST-NET-1, documentation and examples.
192.88.99.0/24 192.88.99.0–192.88.99.255 256 Internet Reserved. Formerly used for IPv6 to IPv4 relay (included IPv6 address block 2002::/16).
192.168.0.0/16 192.168.0.0–192.168.255.255 65536 Private network Used for local communications within a private network.
198.18.0.0/15 198.18.0.0–198.19.255.255 131072 Private network Used for benchmark testing of inter-network communications between two separate subnets.
198.51.100.0/24 198.51.100.0–198.51.100.255 256 Documentation Assigned as TEST-NET-2, documentation and examples.
203.0.113.0/24 203.0.113.0–203.0.113.255 256 Documentation Assigned as TEST-NET-3, documentation and examples.
224.0.0.0/4 224.0.0.0–239.255.255.255 268435455 Internet In use for IP multicast. (Former Class D network).
240.0.0.0/4 240.0.0.0–255.255.255.254 268435455 Internet Reserved for future use. (Former Class E network).
255.255.255.255/32 255.255.255.255 1 Subnet Reserved for the "limited broadcast" destination address.

Loopback

The class A network 127.0.0.0 (classless network 127.0.0.0/8) is reserved for loopback. IP packets whose source addresses belong to this network should never appear outside a host. Packets received on a non-loopback interface with a loopback source or destination address must be dropped.

First and last subnet addresses

The first address in a subnet is used to identify the subnet itself. In this address all host bits are 0. To avoid ambiguity in representation, this address is reserved. The last address has all host bits set to 1. It is used as a local broadcast address for sending messages to all devices on the subnet simultaneously. For networks of size /24 or larger, the broadcast address always ends in 255.

Example

192.168.5.0/24

Binary Form Dot-decimal notation
Network space 11000000.10101000.00000101.00000000 192.168.5.0
Broadcast address 11000000.10101000.00000101.11111111 192.168.5.255

192.168.0.1/28

Binary Form Dot-decimal notation
Network space 11000000.10101000.00000000.00000000 192.168.0.0
Broadcast address 11000000.10101000.00000000.00001111 192.168.0.15

10.0.0.1/16

Binary Form Dot-decimal notation
Network space 00001010.00000000.00000000.00000000 10.0.0.0
Broadcast address 00001010.00000000.11111111.11111111 10.0.255.255

100.200.0.1/12

Binary Form Dot-decimal notation
Network space 01101000.11000000.00000000.00000000 100.192.0.0
Broadcast address 01101000.11001111.11111111.11111111 100.207.255.255

IPV6