TCP segment structure in Computer Networks - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to identify the field that holds the source port number in a TCP segment.

Computer Networks

The first 16 bits of a TCP segment represent the [1].

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Aacknowledgment number

Bsource port

Csequence number

Ddestination port

Attempts:

3 left

💡 Hint

Common Mistakes

Confusing source port with destination port.

Thinking sequence number is at the start.

The first 16 bits in a TCP segment header specify the source port number, which identifies the sending application.

2fill in blank

medium

Complete the code to identify the size of the TCP header length field.

Computer Networks

The TCP header length field is [1] bits long.

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A4

B8

C16

D32

Attempts:

3 left

💡 Hint

Common Mistakes

Confusing header length field size with other fields like sequence number.

Assuming it is 8 bits or more.

The TCP header length field is 4 bits long and indicates the size of the TCP header in 32-bit words.

3fill in blank

hard

Fix the error in the statement about the TCP flags field size.

Computer Networks

The TCP flags field is [1] bits long.

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A6

B8

C12

D9

Attempts:

3 left

💡 Hint

Common Mistakes

Assuming only 6 or 8 bits for flags.

Forgetting the NS flag bit.

The TCP flags field is 9 bits long, including flags like SYN, ACK, FIN, and others.

4fill in blank

hard

Fill both blanks to complete the description of the TCP checksum and urgent pointer fields.

Computer Networks

The TCP checksum field is [1] bits long and is followed by the urgent pointer field which is [2] bits long.

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A16

B8

C32

D12

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing up the sizes of checksum and urgent pointer fields.

Assuming one is 8 bits.

Both the TCP checksum and urgent pointer fields are 16 bits long each.

5fill in blank

hard

Fill all three blanks to complete the dictionary comprehension that maps TCP header fields to their sizes in bits, filtering only fields larger than 16 bits.

Computer Networks

tcp_fields = {"[1]": [2], "[3]": 32, "window": 16, "checksum": 16}
large_fields = {field: size for field, size in tcp_fields.items() if size > 16}

Drag options to blanks, or click blank then click option'

Asequence_number

B32

Cacknowledgment_number

D16

Attempts:

3 left

💡 Hint

Common Mistakes

Including fields with size 16 bits in the filtered dictionary.

Mixing up field names or sizes.

The sequence number and acknowledgment number fields are 32 bits each, so they are included in the filtered dictionary.