What is Topologies?
You can cable and construct computer networks in different ways. Nowadays the most common variant is the so called star network, where all computer are connected
to a central device.The disadvantage is that this device is a single point of failure and the whole network will break down if it gets lost.
This disadvantage can be circumstanced by using redundant (multiple) devices.
Another possibility is to connect all computers in one long row one after the other, the so called bus network. The disadvantage of this topology is that each computer must have two network cards and depending on the destination the traffic gets routed through all computers of the net. If one of them fails or has too high a load the connections behind
that host are lost.
The author has seen only a few bus networks this decade and all consisted of two computers directly connected to guarantee time critical or traffic intensive services like database replication, clustering of application servers or synchronization of backup servers. In all cases the reason for a bus network was to lower the load of the star network.
As last variant the ring network should be mentioned, which as the name implies connects all computers in a circle. The ring network has the same disadvantages as a bus network except that the network will only fail partly if a computer gets lost as long as
the net can route the traffic the other way round. The author has not seen a productive ring
network, but some wise guys whisper that it it the topology of backbones used by ISPs and
large companies.
Additionally one often reads about LAN (Local Area Network), WAN (Wide Area Network) and sometimes even about MAN (Middle Area Network). A LAN is a local network that’s most of the time limited to a building, floor or room.
In modern networks most computers are connected on a LAN over one or more switches.
Multiple LANs connected over a router or VPN are called MAN.
~ @geekcode
You can cable and construct computer networks in different ways. Nowadays the most common variant is the so called star network, where all computer are connected
to a central device.The disadvantage is that this device is a single point of failure and the whole network will break down if it gets lost.
This disadvantage can be circumstanced by using redundant (multiple) devices.
Another possibility is to connect all computers in one long row one after the other, the so called bus network. The disadvantage of this topology is that each computer must have two network cards and depending on the destination the traffic gets routed through all computers of the net. If one of them fails or has too high a load the connections behind
that host are lost.
The author has seen only a few bus networks this decade and all consisted of two computers directly connected to guarantee time critical or traffic intensive services like database replication, clustering of application servers or synchronization of backup servers. In all cases the reason for a bus network was to lower the load of the star network.
As last variant the ring network should be mentioned, which as the name implies connects all computers in a circle. The ring network has the same disadvantages as a bus network except that the network will only fail partly if a computer gets lost as long as
the net can route the traffic the other way round. The author has not seen a productive ring
network, but some wise guys whisper that it it the topology of backbones used by ISPs and
large companies.
Additionally one often reads about LAN (Local Area Network), WAN (Wide Area Network) and sometimes even about MAN (Middle Area Network). A LAN is a local network that’s most of the time limited to a building, floor or room.
In modern networks most computers are connected on a LAN over one or more switches.
Multiple LANs connected over a router or VPN are called MAN.
~ @geekcode
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~ @geekcode
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~ @geekcode
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ISO/OSI MODEL ?
According to the pure doctrine the ISO/OSI layer model, technically separates a computer network into seven layers.
Each layer has a clearly defined task and each packet passes them one after another in
the operating systems kernel up to the layer it’s operating on.
~ @geekcode
According to the pure doctrine the ISO/OSI layer model, technically separates a computer network into seven layers.
Each layer has a clearly defined task and each packet passes them one after another in
the operating systems kernel up to the layer it’s operating on.
~ @geekcode
What is Protocol?
A protocol is a set of rules and standards that basically define a language that devices can use to communicate. There are a great number of protocols in use extensively in networking, and they are often implemented in different layers.
Some low level protocols are TCP, UDP, IP, and ICMP. Some examples of application layer protocols, built on these lower protocols, are HTTP (for accessing web content), SSH, TLS/SSL, and FTP.
~ @geekcode
A protocol is a set of rules and standards that basically define a language that devices can use to communicate. There are a great number of protocols in use extensively in networking, and they are often implemented in different layers.
Some low level protocols are TCP, UDP, IP, and ICMP. Some examples of application layer protocols, built on these lower protocols, are HTTP (for accessing web content), SSH, TLS/SSL, and FTP.
~ @geekcode
What is Firewall?
A firewall is a program that decides whether traffic coming into a server or going out should be allowed. A firewall usually works by creating rules for which type of traffic is acceptable on which ports. Generally, firewalls block ports that are not used by a specific application on a server.
~ @geekcode
A firewall is a program that decides whether traffic coming into a server or going out should be allowed. A firewall usually works by creating rules for which type of traffic is acceptable on which ports. Generally, firewalls block ports that are not used by a specific application on a server.
~ @geekcode
What is NAT?
NAT stands for network address translation. It is a way to translate requests that are incoming into a routing server to the relevant devices or servers that it knows about in the LAN. This is usually implemented in physical LANs as a way to route requests through one IP address to the necessary backend servers.
~ @geekcode
NAT stands for network address translation. It is a way to translate requests that are incoming into a routing server to the relevant devices or servers that it knows about in the LAN. This is usually implemented in physical LANs as a way to route requests through one IP address to the necessary backend servers.
~ @geekcode
Why use packets?
it could be possible to send files and data over the Internet without chopping them down into small packets of information. One computer could send data to another computer in the form of a long unbroken line of bits (small units of information, communicated as pulses of electricity that computers can interpret).
However, such an approach quickly becomes impractical when more than two computers are involved. While the long line of bits passed over the wires between the two computers, no third computer could use those same wires to send information — it would have to wait its turn.
In contrast to this approach, the Internet is a "packet switching" network. Packet switching refers to the ability of networking equipment to process packets independently from each other. It also means that packets can take different network paths to the same destination, so long as they all arrive at the destination. (In certain protocols, packets do need to arrive at their final destinations in the correct order, even if each packet took a different route to get there.)
Because of packet switching, packets from multiple computers can travel over the same wires in basically any order. This enables multiple connections to take place over the same networking equipment at the same time. As a result, billions of devices can exchange data on the Internet at the same time, instead of just a handful.
~ @geekcode
it could be possible to send files and data over the Internet without chopping them down into small packets of information. One computer could send data to another computer in the form of a long unbroken line of bits (small units of information, communicated as pulses of electricity that computers can interpret).
However, such an approach quickly becomes impractical when more than two computers are involved. While the long line of bits passed over the wires between the two computers, no third computer could use those same wires to send information — it would have to wait its turn.
In contrast to this approach, the Internet is a "packet switching" network. Packet switching refers to the ability of networking equipment to process packets independently from each other. It also means that packets can take different network paths to the same destination, so long as they all arrive at the destination. (In certain protocols, packets do need to arrive at their final destinations in the correct order, even if each packet took a different route to get there.)
Because of packet switching, packets from multiple computers can travel over the same wires in basically any order. This enables multiple connections to take place over the same networking equipment at the same time. As a result, billions of devices can exchange data on the Internet at the same time, instead of just a handful.
~ @geekcode