Connectionless Protocol

What is Connectionless communication?

A connectionless protocol like UDP sends data packets without establishing a dedicated end-to-end connection, meaning each packet is treated independently.

Why is Connectionless communication useful?

Connectionless communication is useful for applications where speed and low latency matter more than guaranteed delivery, such as video streaming, gaming, and voice calls.

How does Connectionless communication work?

UDP sends datagrams individually without handshakes or acknowledgments. There is no guarantee that packets will arrive or arrive in order.

Where is Connectionless communication used?

Commonly used in real-time applications like live broadcasts, online multiplayer games, DNS queries, and VoIP.

Which OSI layer does Connectionless communication belong to?

Connectionless protocols like UDP operate at the Transport Layer (Layer 4) of the OSI model.

Is Connectionless communication Windows specific?

No, connectionless communication via UDP is implemented on all major platforms including Windows, Linux, and macOS.

Is Connectionless communication Linux specific?

No, UDP is universally supported across all operating systems as a fundamental part of the internet protocol suite.

Which Transport Protocol is used by Connectionless communication?

The primary transport protocol used for connectionless communication is UDP (User Datagram Protocol).

Is Connectionless communication using client-server model?

Yes, connectionless communication is often used in client-server models where speed is prioritized over reliability, such as DNS servers responding to client queries.

Topics in this section,

  • In this section, you are going to learn

  • Terminology

  • Version Info

  • setup

Connectionless Protocol - Testcases

S.No

Test Case

Description

Expected Result

1

Send Datagram

Send a single UDP packet

Packet sent successfully

2

Receive Datagram

Receive a UDP packet

Packet received successfully

3

No Handshake

Start communication

No connection setup required

4

No Acknowledgment

Send packet

No ACK expected

5

Packet Loss

Drop packet in transit

No retransmission

6

Packet Duplication

Duplicate packet

Receiver may get multiple copies

7

Packet Reordering

Reorder packets

Receiver gets out-of-order data

8

No Flow Control

Send burst of packets

Receiver may drop excess packets

9

No Congestion Control

Send during congestion

Packets may be lost

10

Stateless Communication

Send without session

Server handles each packet independently

11

Broadcast Packet

Send to broadcast address

All nodes receive packet

12

Multicast Packet

Send to multicast group

Group members receive packet

13

Unicast Packet

Send to single host

Target host receives packet

14

Port Unreachable

Send to closed port

ICMP error may be returned

15

No Retransmission

Drop packet

No retry attempted

16

High Throughput

Send many packets quickly

High-speed transmission

17

Low Latency

Measure delay

Minimal transmission delay

18

Packet Size Limit

Send max-size packet

Packet accepted ( 65,535 bytes)

19

Oversized Packet

Exceed size limit

Packet dropped or fragmented

20

Fragmented Packet

Send fragmented datagram

Reassembled at receiver

21

Corrupted Packet

Simulate bit error

Packet may be discarded

22

No Ordering Guarantee

Send multiple packets

Order not guaranteed

23

Stateless Server

Server handles each request independently

No session tracking

24

Stateless Client

Client sends without session

No connection state

25

Packet with Delay

Introduce delay

Packet still received

26

Packet with Jitter

Vary delay between packets

Receiver handles jitter

27

Packet with Loss

Drop random packets

No retransmission

28

Packet with Duplication

Send same packet twice

Receiver may get duplicates

29

Packet with Reordering

Change packet order

Receiver gets unordered data

30

Packet with TTL Expiry

Set low TTL

Packet discarded en route

31

Packet with Invalid Checksum

Corrupt checksum

Packet dropped

32

Packet with Valid Checksum

Correct checksum

Packet accepted

33

Packet to Invalid IP

Send to wrong address

Packet lost

34

Packet to Valid IP

Send to correct address

Packet received

35

Packet to Closed Port

Send to unused port

ICMP error may be returned

36

Packet to Open Port

Send to listening port

Packet processed

37

Packet Flooding

Send rapid packets

May cause packet loss

38

Packet Logging

Log incoming packets

Logs generated

39

Packet Monitoring

Monitor traffic

Packets visible in sniffer

40

Packet Filtering

Apply firewall rules

Packets blocked or allowed

41

NAT Traversal

Send through NAT

Packet reaches destination

42

VPN Routing

Send over VPN

Packet tunneled successfully

43

Proxy Routing

Send via proxy

Packet forwarded

44

IPv6 Support

Send over IPv6

Packet transmitted

45

IPv4 Support

Send over IPv4

Packet transmitted

46

DNS Query

Send UDP DNS request

Response received

47

VoIP Packet

Send RTP over UDP

Audio transmitted

48

Video Stream

Send video over UDP

Stream received

49

Game Packet

Send game data

Real-time update received

50

UDP Hole Punching

Establish peer-to-peer

Connection established

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