Course Overview
A computer network is a set of computers sharing resources. They communicate through common communication protocols over digital interconnections, which are made up of telecommunication network technologies (based on physically wired, optical, and wireless).
There are a few restrictions to consider that make desigining computer networks a challenge:
- distance
- processing
- medium
- routing
- visibility
The internet is the global system of interconnected computer networks that use the internet protocol suite (TCP/IP) to communicate between networks and devices. In other words, a network of networks that consist of private, public, academic, business, and government networks of local to global scope.
Layers
There are services that layer on top of one another. A layer will export services to the layer above and relies on services from the layer below.
In the internet protocol suite, there are the following layers with the following responsibilities:
- Application: bi-directional reliable byte stream
- Transport: reliable in-order delivery of data flow, flow control, and congestion control. E.g., TCP/UDP
- Network: delivers packets end-to-end, best-effort delivery. E.g., IP
- Link: delivers data over a single. E.g., ethernet, wifi.
Example: hypertext transfer protocol (HTTP)
- application: get
index.html - transport: connection ID
- network: source & destination
- link: link address
Example: 4 layer internet model
There are three sections, all linked through the bottom link layer: source host, routers, and destination host. The hosts have all four layers and the routers only have the bottom two.
Course Logistics
Textbooks:
Linked from Application Layer, Computer Networks