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The transport services¶
- The services play an important role in computer networks since they define what the user can really expect. Selection all the correct affirmations about the connectionless network service ?
The connectionless network service can only transfer SDUs of fixed size
- The connection-oriented service is perhaps the most widely used transport service. The interactions between the user of the service and the underlying protocol can be represented as the exchange of various primitives. Considering the interactions between a user of the connection-oriented transport service and its provider, which of the following affirmations are correct ? Select all the correct ones.
- Consider the connection-oriented transport service. Among the following affirmations about this service, select the ones that are correct.
A transport service provider may itself issue a Disconnect.indication to gracefully terminate a connection.
- Which of the following affirmations correspond to the behaviour of the network layer ? Select all the correct ones.
- Which of the following mechanisms are likely to be used inside a protocol that provides the unreliable connectionless transport service running on top of an unreliable connectionless network layer. ? Select all the applicable mechanisms.
A checksum to detect transmission errors.
A CRC to detect transmission errors.
Sequence numbers to detect out-of-order data.
A retransmission timer to retransmit lost data.
A connection establishment mechanism.
- The three-way handshake allows to negotiate successfully the establishment of a transport connection. Among the following time-sequence diagrams, which is the one that corresponds to a valid three-way handshake ?
The three-way handshake allows to negotiate successfully the establishment of a transport connection. Consider a transport connection that begins which the exchange of two segments as shown in the figure below.
Consider what happens after the exchange of these two segments. Only one of the affirmations below is correct. Which one ?
If Host B receives again CR(seq=12345), it will discard the duplicate segment.
At this stage, the connection is established and all CA segments that arrive should be considered as duplicate and discarded.