3) Network Components

Parts of a Network:

Consists of various nodes applications or in direct way we can say :

replacing nodes with various devices of a network system.

A host can be connected to multiple apps.

For connecting two hosts we need at least one router.

Component Names:

Types of Links:

• Full-duplex

– Bidirectional

• Half-duplex

– Bidirectional

• Simplex

– unidirectional

Wireless Links:

• Message is broadcast
– Received by all nodes in range

– Not a good fit with our model

• Often show logical links

– Not all possible connectivity

A Small Network:

• Connect a couple of computers

• Next, a large network …

Example Networks:

• Commonly known by type of technology or their purpose

• WiFi (802.11)

• Enterprise / Ethernet

• ISP (Internet Service Provider)

• Cable / DSL

• Mobile phone / cellular (2G, 3G, 4G)

• Bluetooth

• Telephone

• Satellite ...

Network names by scale:

Internetworks:

• An internetwork, or internet, is what you get when you join networks together

– Just another network

• The Internet (capital “I”) is the internet we all use

Network Boundaries:

• What part is the “network”?

• What part represents an “ISP”?

• Cloud as a generic network

Key Interfaces:

• Between (1) apps and network,

and (2) network components

– More formal treatment later on

1. Network-application interfaces

define how apps use the network

– Sockets are widely used in practice

2. Network-network interfaces

define how nodes work together

– Traceroute can peek in the network

Previous: 1-2 Uses Of Networks

Next: 1-4 Sockets