Instant Mail

Instant Messaging

Internet Messaging

Intranet Messaging

Internet Messaging

multiplexing

multitasking

encapsulation

segmentation

decapsulation

Intermediary devices

Communication servers

Security devices

Network access devices

Modems

Channel - Encoder - Decoder - Transmitter - Receiver

Encoder - Transmitter - Channel - Decoder - Receiver

Encoder - Channel - Transmitter - Decoder - Receiver

Encoder - Transmitter - Channel - Receiver - Decoder

Transmitter - Encoder - Channel - Decoder - Receiver

The TCP/IP model is a reference model.

TCP/IP is an open standard, which means that one company does not control it.

Application layer of TCP/IP model works similar to the application layers of application, presentation and session layers of OSI models.

Application, transport, internet and network are four layers of TCP/IP model.

The TCP/IP model defines the four communication functions that protocols perform.

Port 53

Port 80

Post 67

Port 110

Port 25

OSI stands for Open System Internet.

The OSI model is an internetwork reference model developed by the International Organisation for Standardisation (ISO).

The OSI model is used for referring to the process of communication, not to regulate it.

In OSI model, communication process begins at the application layer of the source and data is passed down to each lower layer to be encapsulated with the supporting data until it reaches the physical layer and is put out on the media.

Each layer provides data services to the layer directly above by preparing information coming down the model or going up.

Data PDU

Packet PDU

Frame PDU

Segment PDU

Bits PDU

FTP protocol

Telnet

Post Office Protocol

Simple Mail Transfer Protocol

Domain Name System

Trivial File Transfer Protocol (TFTP)

Internet Relay Chat (IRC)

Routing Information Protocol (RIP)

Real-Time Transport Protocol (RTP)

Session Initiation Protocol (SIP)

TCP protocol is a connection oriented protocol.

TCP does not resend any data segments that are not acknowledged as being received at the destination.

TCP does not pass data to the network until it knows that the destination is ready to receive it.

TCP uses a mechanism of the three-way handshake, timers, acknowledgments and dynamic windowing to achieve reliable features.

TCP provides congestion control through the use of flow control and dynamic window sizes.

UDP is a connectionless protocol that provides the basic transport layer functions.

UDP is transaction based protocol.

UDP reassembles the data in the order that it was received and forwards it to the application.

UDP has more overhead than TCP protocol.

UDP stands for User Datagram Protocol.

Segmentation

Encapsulation

Routing

Addressing packets with an IP address

Decapsulation

IPv4 is a Network Layer Protocol used as a basic protocol of the internet.

IPv4 is a media independent protocol.

The IPv4 protocol describes services and packet structure that are used to encapsulate UDP datagrams or TCP segments handed down from the transport layer of the OSI model.

IPv4 is a reliable protocol.

IPv4 is a connectionless protocol.

A static routing is a routing where route information can be manually configured on the router.

Static routing does not require a network administrator for initial setup and for any changes to the routes.

Static routing is very reliable and the router does not use much overhead to process the packets.

Static routing does not update automatically and has higher continuing administrative costs.

An example of static routing is default routing.

Mapping upper-layer addresses to lower-layer addresses

Routing information exchange by some routing protocols

Newsfeed

Distribution of software

Video and audio broadcast

The communication using a unicast packet can be forwarded through an internetwork using different addresses.

The process of sending a packet from one host to an individual host is called unicasting.

Unicasting is the host-to-host communication in both a client/server and a peer-to-peer network.

In unicasting, the host addresses assigned to the two end devices are used as the source and destination of IPv4 addresses.

Unicasting places the IPv4 address of the destination host in the packet header as the destination address.

host address

broadcast address

network address

destination address

IP address

physical media

peers

physical topology

physical address

pads

Loopback address

Link-local address

Default route address

Test-net address

Experimental address

Quality field

Type field

Addressing or naming field: the destination and/or source devices

Data field

Start and stop indicator fields

ISP is an internet service provider which provides Domain Name System (DNS) services, email services, etc. to the customers.

Tier 2 ISPs tend to provide services to retail and home markets in a specific locale.

ISPs are designated by a hierarchy based on their level of connectivity to the internet backbone.

At the top of the ISP hierarchy are tier 1 ISPs which provide reliability and high speed services to the customers.

ISP supplies a small number of usable IPv4 addresses (6 or14) to its customers as a part of its services.

forwarding

flow control

fragmentation

flooding

filtering

Only one station transmits at a time.

Devices wanting to transmit FDDI must wait for their turn.

Some networks use token passing.

Collisions exist in this method.

Token Ring and FDDI use this method.

subnet

subnet mask

slash format

octal number

binary number