January 26, 2020
Amitraj
Network Devices - Network device are components used to connect computers and other electronic devices together so that they can share files or resources like printers or fax machines.
Devices used to setup a local area network (LAN) are the most common types of network devices used by the public.
Internetworking -
first:
-> An Internetwork is a collection of individual networks, connected by intermediate networking devices, that functions as a single large network.
second:
-> An internetworking device is a widely-used term for any hardware within networks that connect different network resources. Key devices that comprise a network are routers, bridges, repeaters and gateways.
All devices have separately installed scope features, per network requirements and scenarios.
Some of the internetworking and networking devices are:-
1. Network Hub:-
Network Hub is a networking device which is used to connect multiple network hosts. A network hub is also used to do data transfer. The data is transferred in terms of packets on a computer network. So when a host sends a data packet to a network hub, the hub copies the data packet to all of its ports connected to. Like this, all the ports know about the data and the port for whom the packet is intended, claims the packet.
2. Network Switch:-
Like a hub, a switch also works at the layer of LAN (Local Area Network) but you can say that a switch is more intelligent than a hub. While hub just does the work of data forwarding, a switch does 'filter and forwarding' which is a more intelligent way of dealing with the data packets.
So, when a packet is received at one of the interfaces of the switch, it filters the packet and sends only to the interface of the intended receiver. For this purpose, a switch also maintains a CAM (Content Addressable Memory) table and has its own system configuration and memory. CAM table is also called as forwarding table or forwarding information base (FIB).
3. Network Router:-
A router is a network device which is responsible for routing traffic from one to another network. These two networks could be a private company network to a public network. You can think of a router as a traffic police who directs different network traffic to different directions.
4. Bridge:-
If a router connects two different types of networks, then a bridge connects two subnetworks as a part of the same network. You can think of two different labs or two different floors connected by a bridge.
5. Repeater:-
A repeater is an electronic device that amplifies the signal it receives. In other terms, you can think of repeater as a device which receives a signal and retransmits it at a higher level or higher power so that the signal can cover longer distances.
For example, inside a college campus, the hostels might be far away from the main college where the ISP line comes in. If the college authority wants to pull a wire in between the hostels and main campus, they will have to use repeaters if the distance is much because different types of cables have limitations in terms of the distances they can carry the data for.
6. Modem:-
A Modem is somewhat a more interesting network device in our daily life. So if you have noticed around, you get an internet connection through a wire (there are different types of wires) to your house. This wire is used to carry our internet data outside to the internet world.
-> However, our computer generates binary data or digital data in forms of 1s and 0s and on the other hand, a wire carries an analog signal and that's where a modem comes in.
-> A modem stands for (Modulator+Demodulator). That means it modulates and demodulates the signal between the digital data of a computer and the analog signal of a telephone line.
7. Gateway:-
A gateway, as the name suggests, is a passage to connect two networks together that may work upon different networking models. They basically work as the messenger agents that take data from one system, interpret it, and transfer it to another system. Gateways are also called protocol converters and can operate at any network layer. Gateways are generally more complex than switch or router.
8. Firewall:- A firewall is a security devices designed to prevent unauthorized access to or from a private network. You can implement a firewall in either hardware or software form, or a combination of both. Firewalls prevent unauthorized internet users from accessing private networks connected to the internet, especially intranets. All messages entering or leaving the intranet (the local network to which you are connected) must pass through the firewall, which examines each message and blocks those that do not meet the specified security criteria.
-> Harware v/s Software firewall -
Hardware firewalls: These firewalls are released either as standalone products for corporate use, or more often, as a built-in component of a router or other networking device. They are considered an essential part of any traditional security system and network configuration. Hardware firewalls will almost always come with a minimum of four network ports that allow connections to multiple systems. For larger networks, a more expansive networking firewall solution is available.
Software firewalls: These are installed on a computer, or provided by an OS or network device manufacturer. They can be customized, and provide a smaller level of control over functions and protection features. A software firewall can protect a system from standard control and access attempts, but have trouble with more sophisticated network breaches.
-> Several types of firewalls exist -
1. Packet filtering: The system examines each packet entering or leaving the network and accepts or rejects it based on user-defined rules. Packet filtering is fairly effective and transparent to users, but it is difficult to configure. In addition, it is susceptible to IP spoofing.
2. Circuit-level gateway implementation: This process applies security mechanisms when a TCP or UDP connection is established. Once the connection has been made, packets can flow between the hosts without further checking.
3. Acting as a proxy server: A proxy server is a type of gateway that hides the true network address of the computer(s) connecting through it. A proxy server connects to the internet, makes the requests for pages, connections to servers, etc., and receives the data on behalf of the computer(s) behind it. The firewall capabilities lie in the fact that a proxy can be configured to allow only certain types of traffic to pass (for example, HTTP files, or web pages). A proxy server has the potential drawback of slowing network performance, since it has to actively analyze and manipulate traffic passing through it.
4. Web application firewall: A web application firewall is a hardware appliance, server plug-in, or some other software filter that applies a set of rules to a HTTP conversation. Such rules are generally customized to the application so that many attacks can be identified and blocked.
Devices used to setup a local area network (LAN) are the most common types of network devices used by the public.
Internetworking -
first:
-> An Internetwork is a collection of individual networks, connected by intermediate networking devices, that functions as a single large network.
second:
-> An internetworking device is a widely-used term for any hardware within networks that connect different network resources. Key devices that comprise a network are routers, bridges, repeaters and gateways.
All devices have separately installed scope features, per network requirements and scenarios.
Some of the internetworking and networking devices are:-
1. Network Hub:-
Network Hub is a networking device which is used to connect multiple network hosts. A network hub is also used to do data transfer. The data is transferred in terms of packets on a computer network. So when a host sends a data packet to a network hub, the hub copies the data packet to all of its ports connected to. Like this, all the ports know about the data and the port for whom the packet is intended, claims the packet.
2. Network Switch:-
Like a hub, a switch also works at the layer of LAN (Local Area Network) but you can say that a switch is more intelligent than a hub. While hub just does the work of data forwarding, a switch does 'filter and forwarding' which is a more intelligent way of dealing with the data packets.
So, when a packet is received at one of the interfaces of the switch, it filters the packet and sends only to the interface of the intended receiver. For this purpose, a switch also maintains a CAM (Content Addressable Memory) table and has its own system configuration and memory. CAM table is also called as forwarding table or forwarding information base (FIB).
3. Network Router:-
A router is a network device which is responsible for routing traffic from one to another network. These two networks could be a private company network to a public network. You can think of a router as a traffic police who directs different network traffic to different directions.
4. Bridge:-
If a router connects two different types of networks, then a bridge connects two subnetworks as a part of the same network. You can think of two different labs or two different floors connected by a bridge.
5. Repeater:-
A repeater is an electronic device that amplifies the signal it receives. In other terms, you can think of repeater as a device which receives a signal and retransmits it at a higher level or higher power so that the signal can cover longer distances.
For example, inside a college campus, the hostels might be far away from the main college where the ISP line comes in. If the college authority wants to pull a wire in between the hostels and main campus, they will have to use repeaters if the distance is much because different types of cables have limitations in terms of the distances they can carry the data for.
6. Modem:-
A Modem is somewhat a more interesting network device in our daily life. So if you have noticed around, you get an internet connection through a wire (there are different types of wires) to your house. This wire is used to carry our internet data outside to the internet world.
-> However, our computer generates binary data or digital data in forms of 1s and 0s and on the other hand, a wire carries an analog signal and that's where a modem comes in.
-> A modem stands for (Modulator+Demodulator). That means it modulates and demodulates the signal between the digital data of a computer and the analog signal of a telephone line.
7. Gateway:-
A gateway, as the name suggests, is a passage to connect two networks together that may work upon different networking models. They basically work as the messenger agents that take data from one system, interpret it, and transfer it to another system. Gateways are also called protocol converters and can operate at any network layer. Gateways are generally more complex than switch or router.
8. Firewall:- A firewall is a security devices designed to prevent unauthorized access to or from a private network. You can implement a firewall in either hardware or software form, or a combination of both. Firewalls prevent unauthorized internet users from accessing private networks connected to the internet, especially intranets. All messages entering or leaving the intranet (the local network to which you are connected) must pass through the firewall, which examines each message and blocks those that do not meet the specified security criteria.
-> Harware v/s Software firewall -
Hardware firewalls: These firewalls are released either as standalone products for corporate use, or more often, as a built-in component of a router or other networking device. They are considered an essential part of any traditional security system and network configuration. Hardware firewalls will almost always come with a minimum of four network ports that allow connections to multiple systems. For larger networks, a more expansive networking firewall solution is available.
Software firewalls: These are installed on a computer, or provided by an OS or network device manufacturer. They can be customized, and provide a smaller level of control over functions and protection features. A software firewall can protect a system from standard control and access attempts, but have trouble with more sophisticated network breaches.
NOTE: A firewall is considered an endpoint protection technology. In protecting private information, a firewall can be considered a first line of defense, but it cannot be the only defense.
-> Several types of firewalls exist -
1. Packet filtering: The system examines each packet entering or leaving the network and accepts or rejects it based on user-defined rules. Packet filtering is fairly effective and transparent to users, but it is difficult to configure. In addition, it is susceptible to IP spoofing.
2. Circuit-level gateway implementation: This process applies security mechanisms when a TCP or UDP connection is established. Once the connection has been made, packets can flow between the hosts without further checking.
3. Acting as a proxy server: A proxy server is a type of gateway that hides the true network address of the computer(s) connecting through it. A proxy server connects to the internet, makes the requests for pages, connections to servers, etc., and receives the data on behalf of the computer(s) behind it. The firewall capabilities lie in the fact that a proxy can be configured to allow only certain types of traffic to pass (for example, HTTP files, or web pages). A proxy server has the potential drawback of slowing network performance, since it has to actively analyze and manipulate traffic passing through it.
4. Web application firewall: A web application firewall is a hardware appliance, server plug-in, or some other software filter that applies a set of rules to a HTTP conversation. Such rules are generally customized to the application so that many attacks can be identified and blocked.
