UTS.31270
BScIT 31270 Networking Essentials
Resources
Lab Notes
In the lab: the yellow socket for LAN, white for Internet.
Course Notes
Errors I discovered in Cisco's material
1.3 The Network as a Platform
1.3.2.1
Four elements of a network:
- Rules
- Medium
- Messages
- Devices
1.3.2.4
| Service | Protocol ("Rules") | Acronym |
|---|---|---|
| World Wide Web | Hypertext Transfer Protocol | HTTP |
| Simple Mail Transfer Protocol | SMTP | |
| Post Office Protocol | POP | |
| Instant Messaging | Extensible Messaging and Presence Protocol | XMPP |
| Open System for Communication in Realtime | OSCAR | |
| IP Telephony | Session Initiation Protocol | SIP |
1.4 The Architecture of the Internet
1.4.1.1
Four characteristics of a network architecture:
- fault tolerance
- scalability
- quality of service
- security
1.4.2.1
Circuit Switched Connection-oriented Networks, such as original telephone networks, required end-to-end circuit establishment; circuits could not be dropped and recreated dynamically; and circuits that were not presently in use, though still connected, wasted resources. Thus the DoD sought to invent the Internet Protocol.
1.4.2.2
Packet Switched Connectionless Networks: a fault tolerant network architecture. No fixed path (e.g. a circuit) is established. Packets are routed according to the best path available at the time. Many paths may be used for a single communication as individual packets are routed to a destination.
1.4.3.1
The internet is implicitly a hierarchy of networks, typically regarded as Tier 1, 2, and 3. Where, roughly, Tier 1 is the 'backbone', Tier 2 high-end commercial, and Tier 3 household and small business. DNS in turn provides distributed hierarchical name services.