N5.2 UDP

Question 1

What does UDP stand for?

Answer 1

User Datagram Protocol

Question 2

Why use UDP not TCP?

Answer 2

• UDP is used by applications that don’t want the delay TCP e.g. online videos/games
• used when reliability is not as important
• mechanisms of UDP ( e.g control of the data transmission rate) can be user-controlled

Question 3

Is UDP connection-oriented or connection-less?

Answer 3

Connection-less

unconfirmed, unreliable service - same as IP

Question 4

What is the 5-tuple for UDP?

Question 5

What is UDP Multicast?

Answer 5

{Many|One}-to-many communication
Destination IP address - multicast group address
Anyone can send to the group
Must be a member of the group to receive
Same reliability as UDP unicast
Popular in LAN discovery protocols - devices/services advertise their presence.

Question 6

Problem with broadcast

Answer 6

one-to-all

risk of traffic storms

Question 7

What are the client-server communication planes?

Answer 7

User plane - data in payload for application
Control plane - info needed for protocols to operate (signalling) e.g. header in packet
Management plane - Configuration info and policy info