53 lines
2.3 KiB
ReStructuredText
53 lines
2.3 KiB
ReStructuredText
.. _intro-network-components:
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==================
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Network components
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==================
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Switches
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~~~~~~~~
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Switches are Multi-Input Multi-Output (MIMO) devices that enable packets
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to travel from one node to another. Switches connect hosts that belong
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to the same layer-2 network. Switches enable forwarding of the
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packet received on one port (input) to another port (output) so that they
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reach the desired destination node. Switches operate at layer-2 in the
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networking model. They forward the traffic based on the destination
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Ethernet address in the packet header.
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Routers
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~~~~~~~
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Routers are special devices that enable packets to travel from one
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layer-3 network to another. Routers enable communication between two nodes
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on different layer-3 networks that are not directly connected to each other.
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Routers operate at layer-3 in the networking model. They route the traffic
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based on the destination IP address in the packet header.
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Firewalls
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~~~~~~~~~
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Firewalls are used to regulate traffic to and from a host or a network.
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A firewall can be either a specialized device connecting two networks or
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a software-based filtering mechanism implemented on an operating system.
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Firewalls are used to restrict traffic to a host based on the rules
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defined on the host. They can filter packets based on several criteria such as
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source IP address, destination IP address, port numbers, connection state,
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and so on. It is primarily used to protect the hosts from unauthorized access
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and malicious attacks. Linux-based operating systems implement firewalls
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through ``iptables``.
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Load balancers
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~~~~~~~~~~~~~~
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Load balancers can be software-based or hardware-based devices that allow
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traffic to evenly be distributed across several servers. By distributing the
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traffic across multiple servers, it avoids overload of a single server thereby
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preventing a single point of failure in the product. This further improves the
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performance, network throughput, and response time of the servers.
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Load balancers are typically used in a 3-tier architecture. In this model,
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a load balancer receives a request from the front-end web server,
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which then forwards the request to one of the available back-end database
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servers for processing. The response from the database server is passed back to
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the web server for further processing.
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