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Commits (2)
This chapters provide an overview of network in general. It introduced the idea of public internet and how the rest of the chapters are being structured.
The internet - A computer network that interconnects hundreds of millions of computing devices. These devices are called hosts or end-systems.
End systems are connected by network of communication links and packet switches.
Links consist of transmission rates measured in bits/sec.
Information being exchanged via links are called packets.
Packet Switch - takes incoming packets and forward it to its destination. Ex: routers
End systems access the internet via ISP, which consist of networks of packet switches and communication links.
Most of these runs the protocols, rules that is defined by people when the internet is made. Common protocols included TCP(Transmission Control Protocol) and IP(Internet Protocol). The listed examples are the two most important ones.
Internet standards are defined by the IETF(Internet Engineering Task Force), and its standard documents are called RFCs(requests for comments).
The internet consist of network of networks, dividing the entire internet into sub sections with ISP routing for easy access.
For home access networks, it consist of DSL, cable, FTTH, Dial-up, and Satellite. Today, the most common networks are DSL and Cable for home access.
DSL(digital subscriber line) uses phone line as a way of accessing ISP where as cable is only for internet access. Cable access require cable modem for internet access, which is a special type of modem to connect to fiber nodes.
With packet transmission, it consist of delays. There are few types of delays:
nodal processing delay - time for examining header
queuing delay - time in queue before send
transmission delay - time to push the packet into the link
propagation delay - time for the packet to get to destination
Together, they added up to total nodal delays.
With the complexity of internet, it is divided into layers for understanding. The book uses the 5 layer model :
Application
Transport
Network
Link
Physical
The OSI model have the additional two layers of Presentation and Session before Transport layer.
Reflection:
Questions:
1. 3 seconds
2. 3.05 seconds
3. 500,000 bits
4. 6.05 seconds
5. 4.05 seconds
6. 30.05 sec
7. 30.05 sec
8. 124 min
9. 122 minutes and 12 seconds
10. 10 Mbps
11. Frame
True/False section
1. F
2. T
3. F
4. F
5. T
6. F
7. F
8. F
9. T
10. F