What is the rationale behind the absence of sequential numbering in ACK packets?

What precisely is an IP address? Is it accurate that mnemonic addresses are so simple to recall? How many domains can a 32-bit representation accommodate? Is there a maximum number of machines permitted to join a domain?

What is/are the advantages and disadvantages of adding more redundancy bit in a message?

I am entirely unaware of what routing is and how it functions. It is essential to have a thorough comprehension of the distinctions between two frequently used routing schemes.

TCP congestion control example. Consider the figure below, where a TCP sender sends 8 TCP segments at t = 1, 2, 3, 4, 5, 6, 7, 8. Suppose the initial value of the sequence number is 0 and every segment sent to the receiver each contains 100 bytes. The delay between the sender and receiver is 5 time units, and so the first segment arrives at the receiver at t = 6. The ACKs sent by the receiver at t = 6, 7, 8, 10, 11, 12 are shown. The TCP segments (if any) sent by the sender at t = 11, 13, 15, 16, 17, 18 are not shown. The segment sent at t=4 is lost, as is the ACK segment sent at t=7. TCP sender t=1 T t=2 t=3 t=4+ t=5- t=6+ t=11 t=12 t=13 t=14 t=15 t=16 t=17 t=18 I data segment data segment data segment data segment data segment data segment data segment data segment ACK ACK ACK ACK ACK ACK Ty A A V V htt TCP receiver t=6 t=7 t=8 t=9 t=10 t=11 t=12 t=13 What does the sender do at t=17? You can assume for this question that no timeouts have occurred.

It is possible for a series of packets to be sent from one host to another over the same connection. Please break down the time it takes for a single package to go from beginning to conclusion. Is it expected that one of the delays would last a certain period of time while the other delay's length will be more malleable?

Suppose Alice and Bob are going to communicate using AES in CBC mode. Unfortunately Alice's message length (in bytes) is not a multiple of 16. Suppose the last block of her message is just a single zero byte. How can she pad out the last block so that she can use CBC mode? Since this needs to be a reversible operation, how does Bob recognize the padding and remove it?

What a router does when it gets a packet with an unknown destination network address is described in the following.

TCP employs a mechanism to mitigate the issue of sequence number wrapping.

Is there a materially different level of unreliability between IP and UDP, and if so, what constitutes that difference? Is there a reason for this, or is it simply something that happened by chance?