Lecture Notes - CS441
Thursday, August 22nd 2024
- Our responsibility to check canvas
- No handwritten hw
- Copy of every week-ppt
- Always check announcements on canvas
Switching
- Logical network topology component
- Determines connection between nodes
- Two methods
- Circuit switching (old one)
- Packet switching (new one)
Circuit switching
- Connection established between two network nodes
- Like dedicated highway, you can’t have a highway for every individual car
- Data follows same initial path selected by switch, monopolizes bandwidth while connected
- Wasted resource
- More popular for live audio, video transmission
Packet switching
- Most popular
- Breaks data into packets before transporting
- Travel any network path to destination
- Finds fastest circuit available at any instance
- Open Shortest Path First
- Don’t need to follow each other
- Don’t need to arrive in sequence
- Reassembled at destination
- Requires speedy connections for live audio, video transmission
- Highway analogy: take this exit, this road etc.
OSI Model
- Theoretical representation describing network communication between two nodes
- Hardware and software independent
- APSTNDP (All people seem to need data processing)
- Application
- Connects to network
- Presentation
- Three functions
- Translate, encrypt, compress
- Session
- Making sure the other party is there
- Ex. making sure email is valid, why send information if bandwidth is not there
- Establishing the session, authenticating user
- Transport
- Delivery
- Network
- Router
- Shortest path to the destination
- Data link
- Network Interface Card
- Ethernet or wireless connection
- Physical
- Cables
- Application
Most important element in computer network is bandwidth.
Note ideas
- Packets
- Switching
- OSPF
- OSI Model