Question

In SCTP, the state of a sender is as follows:

a. The sending queue has chunks 18 to 23.
b. The value of curTSN is 20.
c. The value of the window size is 2000 bytes.
d. The value of inTransit is 200.
If each data chunk contains 100 bytes of data, how many DATA chunks can be sent now? What is the next data chunk to be sent?

Answer 1

Given the SCTP sending conditions provided, up to 18 DATA chunks can be sent within the window size limit. However, only 6 chunks (18 to 23) are available in the sending queue, and the next chunk to be sent is chunk number 20. The correct option is a. The sending queue has chunks 18 to 23.

Step-by-step explanation:

In SCTP (Stream Control Transmission Protocol), the sender's state conditions help determine how many DATA chunks can be sent at any given time. The information provided indicates:

• The sending queue has chunks 18 to 23,
• The value of curTSN is 20,
• The window size is 2000 bytes, and
• The inTransit amount is 200 bytes.

Since each DATA chunk is 100 bytes, and the window size defines the maximum amount of unacknowledged data that can be in transit, we can determine how many DATA chunks can be sent now by calculating the remaining window space.

The current inTransit value is 200 bytes, which means there is still (2000 - 200) = 1800 bytes of window size available. Therefore, a total of 1800 / 100 = 18 DATA chunks can be sent, respecting the window size limit.

However, it's important to note that the sending queue only has chunks 18 to 23 available. This means only 6 chunks are available to be sent. Since the curTSN is 20, the next DATA chunk to be sent will be chunk number 20.

The correct option is a. The sending queue has chunks 18 to 23.