There should be two or more computers to build a computer network. Network devices used to connect computers with each other.
Network Interface Card [NIC] & RJ-45 connector
NIC has an RJ-45 port and is built into the mother board in modern computers.
In the port NIC was a seperate code to be pluged to the mother board.
Network Interface Card [NIC]
RJ-45 connector
Switch & Hub
Switch/Hub acts as the mediator to build a connection between two or more computers.
A guided/wired transmission media is used.
One end is connected to port in the computer and the other end is connected to the port in the Switch / Hub.
Network Switch
Hub
HUB vs SWITCH
The main objective of a Hub is to transmit the signal to a port, which will respond to where the signal was received.
A switch allows you to set up and terminate connections as needed.
Hubs operate at the Physical Layer.
Switches function at the Data Link Layer.
Hubs use broadcast type transmission.
Switches use unicast, multicast as well as broadcast type transmission.
Hub can have maximum 4 ports.
Switch can have 24 to 28 ports.
There is only one collision domain in a Hub.
In a Switch, each port has its own collision domain.
Hubs do not provide packet filtering.
Switches provide packet filtering.
Hub uses half duplex transmission mode.
Switch uses full duplex transmission mode.
Both Hubs and Switches are network connecting devices.
Hubs are basic networking devices that operate at the Physical Layer and they are used to send the data packets to all the connected devices, without any filtration.
A Switch keeps track of the MAC addresses of all connected devices and hence, it can tell which device or system is plugged into which port. When a data packet is received, the switch understands exactly which port it should be sent to.
Wireless Fidelity [Wi-Fi] & Router
A router is a device that is used for forwarding the internet connection to all the connected devices.
A WiFi combines the networking functions of a router and a wireless access point.
A wireless router works much like a wired router, but it replaces wires with wireless radio signals.
Wi-Fi
Router
Modem
The modem acts as a data translator. Digital signals sent from the computer is translated to analog signals and the analog signals send to the computer from the internet is translated to digital signals. This is called MOdulation and DEModulation.
There are different types of MODEMs. Those are internal, external and wireless modems.
Todays routers have a modem inbuilt in the device.
Internal Modem
External Modem
Wireless Modem
MODEM vs ROUTER
A Modem modulates and demodulates signals.
The router is a networking device that allows you to associate various networks with each other for LAN and WAN networks.
It is used for accessing the Internet as it connects your computer to the ISP.
You can access the Internet without the need for a modem.
The modem operates on the Datalink layer.
Router can be operated at the Data Link Layer, Network Layer, and Physical Layer.
The modem does not help to examine the data packet. Therefore, the security threat is always there.
Router examines all data packet before forwarding it, that helps to identify a threat.
It is placed between a telephone line and a router or directly to the computer.
It is placed between a computer network and modem.
Repeater
It is a 2-port device.
A repeater operates at the physical layer of the OSI model.
A Repeater connects two segments of a network cable.
Sometimes it regenerates the signals to proper amplitudes and sends them to the other segment.
If the signal becomes weak, it can copy the signal bit by bit and regenerate it at the original strength.
Repeater
Bridge
A bridge operates at the data link layer of the OSI model.
It can read only the outmost hardware address of the packet but cannot read the IP address.
It reads the outmost section of the data packet to tell where the message is going.
It reduces the traffic on other network segments.
It does not send all the packets. So, a bridge can be programmed to reject packets from a particular network.
Bridge
BRIDGE vs REPEATER
Bridge operates at the data link layer of OSI Model.
Repeater operates at the physical layer of OSI Model.
The complete frames is understand by bridge.
Repeater do not understand complete frames.
Destination address is used in the bridge to determine in case to forward a frame.
Repeater are not able to recognize the destination address.
In the network, if collision occurs in the one segment is not forwarded to another segment by bridge.
Repeater forward the collision from one segment to another, which causes the same issue to be occurred on all other segment in the network.
Bridge connects two network in a well organized manner.
Repeater expands the limit of the signals in the network.
Filtering of the packets in network is achieved by the bridge.
Repeater cannot performs packet filtering.
Bridges are relatively expensive and used to extend a LAN.
Repeater is also used to extend a LAN, but comparably economical than the bridge.
Gateway
A gateway is an internetworking capable of joining together two networks that use different base protocols.
A network gateway can be implemented completely in software, hardware, or a combination of both, depending on the types of protocols they support.
A network gateway can operate at any level of the OSI model.
A broadband router typically serves as the network gateway, although ordinary computers can also be configured to perform equivalent functions.
A gateway is a router or proxy server that routes between networks.
A gateway belongs to the same subnet to which the PC belongs.
Gateway
BRIDGE vs GATEWAY
Bridge works in data link layer.
While it works in all layer.
Bridge connects two different LANs.
While it converts the protocol.
Bridge connects two different LAN working on same protocol.
While gateway will settle for and transfer the packet across networks employing a completely different protocol.
In bridge, data or information is in the form of packet.
Whereas in gateway, data or information is also in the form of packet.
In bridge, format of packet is not changed.
While in gateway, format of packet is changed.
Bridge is not installed in router.
While it installed in router.
Brouter
A brouter is a combination of a Bridge and a Router.
It provides the functions of a bridge and a router, so it can operate at the data link and network layers of the OSI Model.
A Brouter can connect networks that use different protocols.
It can be programmed to work only as a bridge or only as a router.
When it is configured as a bridge, it forwards data packets to the appropriate segment using a specific protocol.
When it is configured as a router, it routes the data packets to the appropriate network using a routed protocol such as IP.
Most brouters are simply routers that have been configured.
The main function of a bridge is to connect two different LAN segments using the same protocol.
A router, on the other hand, is used to route the packets in a network.
Brouter
ROUTER vs BROUTER
A router is a networking device that forwards data packets between computer network.
Brouter is a networking device which is used both as a bridge and as a router,It is combination of network bridge and a router.
It operates at Network layer.
It operates either at Data link layer or a Network layer.
Router stores routing table.
Brouter stores routing table when it is configured as a router and stores MAC address when configured as a bridge.
It takes forwarding decisions based on IP address.
Forwarding decision are taken based on IP address when it is configured as a router, or It takes forwarding decisions based on MAC address when configured as a bridge.
Router transmits data in the form of packets.
Brouter transmits data in the form of packets when it is configured as a router and It transmits data in the form of frames when configured as a bridge.
Router works on more than one broadcast domain.
Brouter works on more than one broadcast domain when it is configured as a router and It works on single broadcast domain when configured as a bridge.
Router is full duplex.
Brouter is full duplex when it is configured as a router and it is half duplex when configured as a bridge.
Firewall
A firewall operates as a secured barrier between internet and network.
Firewalls exist in both forms as software and hardware.
