Commit 820bcbc2 authored by wx002's avatar wx002

update

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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:
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:
This chapter provide a pretty basic overview of networks. It is interesting to see how the network is being structured as an overview. This allows me to understand more of how home networks are being structure and why DSL is much slower compare to cable network. As a personal experience, I finally understand why DSL network cannot provide certain speed compare to cable networks.
Also, it was interesting to see that internet is fragmented into network of networks, where there are different types of network clusters, which is different from each other. It would be interesting to see how different each of these communicate and how security will play a role within different types of communication as a whole.
In regards to the idea of delays, it was interesting to see how packets are transferred and delivered. Even though I know most of these information, this chapter is definitely a good review and provide a better overview of what the internet really is and how computers communicate with each other through ISP.
Questions:
1. 3 seconds
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