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.
1.4.4.1
Here Cisco pimps their QoS agenda. Talking about network "convergence" and all traffic not being alike. QoS entails categorising data and assigning priority (via priority queues).
1.4.5.2
Security measures taken in a network should:
- Prevent unauthorized disclosure or theft of information
- Prevent unauthorized modification of information
- Prevent Denial of Service
Means to achieve these goals include:
- Ensuring confidentiality
- Maintaining communication integrity
- Ensuring availability
1.5.1.1
Trends in networking circa 2008:
- Increasing number of mobile users
- Proliferation of network capable devices
- Expanding range of services
Increased dependence on the network.