OSI model diagram
The delay between the time when an application requests data until it receives the data. Latency can be influenced by:
- The time taken to physically move data onto the network will be determined by the size of the packet and the speed of the network interface.
- The Internet is a heterogenous collection of high-speed and low-speed connections, some more reliable than others. The type of network media and the distance between the device requesting data / location of server or sensor (IoT) where data is stored will influence time.
- Packets inspected and processed by switches and routers takes more time.
- During busy times, network devices may need to buffer packets before inspecting.
Jitter, QoS guarantee and timeliness
- Packet delay variance (irregular latency in data exchanges)
- Really affects user experience in synchronous data exchanges – VoIP conferencing, online gaming
- Quality of Service guarantees
- Best-effort service – no guarantees
- Differentiated service – some traffic is treated better than other traffic
- Guaranteed service – some network bandwidth is reserved for use only by mission-critical applications
- Timeliness of delivery
- Timeliness is the currency of a data packet at the time it is received.
- Hypertext Transfer Protocol
- Methods GET, HEAD, POST, PUT, DELETE, TRACE, CONNECT, PATCH, OPTIONS
- S = secure
- Uses TLS / SSL encryption
- no error checking (unlike TCP)
- faster but more inaccurate
- FTP, VPN, etc.
complete the other research word document activity (below this slide show in the list of digital solutions exam materials). When complete, come back and try the explanations on the following slides in your own words.
explain network transmission principles, including latency, jitter, guarantee and timeliness of delivery, and protocols relevant to the transmission of data over the internet, e.g. HTTP, HTTPS, FTP, VPN, streaming and broadcasting data packets