Network Protocols

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youngkih21

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Network protocols are a set of rules that define how to transmit and receive data

TCP prioritizes reliability over time.

Connection-oriented
- Connection between client and server is established before data is sent
- This connection is established through a process called 3-way Handshake
Reliable
- Lost packets are detected and retransmitted
- Sequence numbers
  - This allows receivers to discard duplicate packets and properly sequence reordered packets
- Acknowledgements
  - This allow senders to determine when to re-transmit lost packets
- Order
  - All bytes received will be in the same order as those sent
- Checksums
  - Ensures the data correctness
Flow Control
- Limit the rate a sender transfers data to a receiver
Congestion Control
- The rate of data entering the network is controlled

UDP prioritizes time over reliability.

UDP is mostly used for video/audio live streaming or online games, where latency is a critical concern and we can afford losing packets occasionally

No Connection
No Reliability
- Does not support most of the feature TCP support
- No acknowledgements, no retransmission, no order, no flow control, no congestion control
Checksums
- Ensures data correctness
Broadcast
- A single message can be transferred to ALL recipients on the subnet simultaneously
Multicast
- A single message can be routed only to intended recipients

Request/Response protocol
- Client submits an HTTP request message to the server and the server sends back an HTTP response
TCP
- Older HTTP protocol versions use TCP as an underlying transport protocol
QUIC (New versions only)
- New(HTTP/3) HTTP protocol versions uses QUIC as an underlying transport protocol
- QUIC is built on top of UDP, but it provides a reliable connection
Persistent Connection (New versions only)
- From old versions of HTTP, the connection is closed after a single request/response pair.
  - This is not efficient, because creating a new connection for every request takes time and CPU utilization because of the TCP handshake process.
- From new versions of HTTP, connection is considered persistent. Which can be used more than one request.
Multiplexing (New versions only)
- Multiple requests are sent over the same TCP connection without waiting for responses.
- Responses are received in an arbitrary order.
Compression
- Allows the content to be compressed on the server before transmission to the client
- Compression decreases transfer latency and increases throughput

Will the Guru