Lecture 3 - Notes
January 11, 2016
Virtual Circuit Switching
With Virtual Circuit Switching we reserve resources based on previous traffic patterns.
Basically emulates a circuit switched connection using packet. Packets are given resource identifiers that define their destination.
Internet History
ARAPAnet was developed by DARPA and the US Department of Defence with the goal of passing packets (using packet switching) on a large distributed network. In addition they wanted the communications network to,
- be redundant and resilient to attack, i.e., nodes being destroyed
- support multiple types of data including multiple communication services
- accommodate a variety of networks and infrastructure
Topologies
| Topology | Delay | Reliability | # of Links |
|---|---|---|---|
| Mesh | short | high | $O(n^2)$ |
| Ring | long | low | $O(n)$ |
| Star | long | low | $O(n)$ |
| Tree | $\lg(n)$ | depends on node | $O(n-1)$ |
In Canada
- CA*net: 1990 -- 1997
- CA*net II: 1995 -- 2000
- CA*net 3: 1998 -- 2002
- CA*net 4: 2002 -- Present