UDP VS TCP

[jonk34567]

How does TCP differ from UDP? (Choose two.)

A.	TCP provides best effort delivery.
B.	TCP provides synchronized communication.
C.	TCP segments are essentially datagrams.
D.	TCP provides sequence numbering of packets.
E.	TCP uses broadcast delivery.

what are the answers ?

[Peter Paluch]

Hello,

It would be very easy and straightforward to provide the correct answers right away, but since you are obviously learning toward a certain knowledge level or perhaps a certification, I humbly believe that it would actually be even more useful if you also told us what answers you believe are right and wrong, and why you think so, and we would guide you through. This will help us point out any misunderstandings you might have about a topic, and that in turn will help you understand it better ;)

So, what do YOU think are the correct and incorrect options?

Best regards,
Peter

[jonk34567]

Only A seems to be correct

[Peter Paluch]

Hello,

Well, "Best effort" means: If the segments arrive, okay. If they get lost, also okay ;) If they get reordered - no one cares :)

Considering that TCP establishes a connection before the exchange of the data itself, and it sequences and reorders the segments into their proper order, and retransmits any data that has not been acknowledged from the receiver, the "best effort" answer does not seem to be correct.

So taking into accout the properties of TCP as just described, what would be your opinion now?

Best regards,
Peter

[jonk34567]

B & D seems to be correct. what about C ?

[Peter Paluch · Accepted solution]

Hello,

Indeed, B and D are correct - TCP provides synchronized communication (the word "synchronized" is somewhat unfortunate but we can think of it as TCP peers establishing the session in a coordinated manner, synchronizing their initial sequence numbers, and keep each other in-sync about what data has already been received), and obviously, TCP performs numbering of sent segments with sequence numbers.

The wording in option 'C' is somewhat vague, in my opinion. Still, the term "datagram" is usually used for unsequenced, unacknowledged, individual messages such as UDP segments. In this sense, 'C' would not be correct.

Best regards,
Peter

[jonk34567]

Thank you very much