Computer Networking

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Computer Network – A computer network is a digital communications network which allows nodes to share resources.

Types of nodes – Router, Switch, Firewall, Server, Client

Clients – A client is a device that accesses a service made available by server.

Server – A server is a device that provides functions or services for clients.

Switches –

1.      Provides connectivity to hosts within the same LAN (Local Area Network).

2.      Switches do not provide connectivity between different LAN’s/ over the internet.

3.      Switches have many network interfaces/ports for end hosts to connect to (usually 24+).

4.      Catalyst 9200, Catalyst 3650 are some switches we use in network.

Routers –

1.      Provides connectivity between LANs.

2.      Hence used to send data over the internet.

3.      Routers have fewer network interfaces than Switches.

4.      ISR1000, ISR900, ISR 4000 are some routers we use in network.

Firewalls –

1.      Firewalls monitor and control network traffic, based on configured rules.

2.      Can be placed inside the network or outside the network.

3.      “Next Generation firewalls” has more modern and advance filtering capabilities.

4.      Types of Firewalls –

·        Network firewalls – Are hardware devices that filter traffic between networks.

·        Host based firewalls – Are software applications that filter traffic entering and existing a host machine, like a PC.

5.      ASA5500-X, Firepower 2100 are some firewalls we use in network.

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