A small unit of data transmitted over a network, containing both the data payload (the actual information) and routing information in headers (source address, destination address, sequence number). Large messages are split into many packets, sent independently, and reassembled at the destination.
Sending data over a network is like sending a book by mail — you break it into chapters (packets), label each one with the destination, and reassemble at the other end.
Showing a random 20 of 50 problems.
Example 1
challenge
Why does packet loss not necessarily mean the connection is broken? Describe the mechanism that hides the loss from the user.
Example 2
medium
Packets arrive in order 3, 1, 2. Using sequence numbers, what order does the receiver assemble them in?Packets arrive at receiver in order 3, 1, 2; sequence numbers allow reassembly as 1, 2, 3
Example 3
hard
Compare circuit switching (phone line) vs packet switching (internet) when a link fails mid-message. Why does packet switching survive?When one link fails, packet switching reroutes remaining packets dynamically; circuit switching would drop the entire call
Example 4
medium
A 30,000-byte message with 1000-byte payloads is sent. How many packets?
Example 5
easy
The actual information a packet carries (not the header) is called the ____.
Example 6
medium
Header overhead is 50 bytes per packet. For 10 packets, total header bytes sent?
Example 7
medium
A 6800-byte file is sent via 1500-byte payloads. How many packets, and how many bytes does the last carry?
Example 8
medium
In TCP, what does the sender do when a packet's ACK doesn't arrive in time?
Example 9
easy
Do all packets of one message always take the same route? Yes or no.
Example 10
medium
A 1 MB file is split into 1000 packets. Packet 500 is lost during transmission. Describe what happens next.Packet 500 is lost between router 1 and router 2; receiver detects the gap and requests retransmission
Example 11
hard
A 50-packet stream sees packet 17 arrive twice. How does the receiver handle the duplicate?Packet 17 is duplicated and arrives via two paths; receiver discards the duplicate based on sequence number
Example 12
easy
Reassembling packets into the original message happens at which end: sender or destination?
Example 13
medium
A message split into 8 packets: 6 take route A, 2 take route B. Does the receiver still reconstruct the original message? Yes or no, and via what?8-packet message: 6 packets take route A, 2 take route B; receiver reassembles all 8 via sequence numbers
Example 14
medium
Why might packets of one download arrive out of order even with no errors?Packets from the same download travel different routes with different delays, causing out-of-order arrival
Example 15
easy
True or false: every packet from one message must take the same path.
Example 16
medium
Header is 40 bytes, payload is 1460 bytes. What fraction of the packet is overhead?
Example 17
easy
A packet contains payload plus what other major part?
Example 18
medium
Describe what information a packet header contains and why each piece is needed.
Example 19
easy
Why are large messages split into packets instead of sent as one big block?
Example 20
hard
For a 100,000-byte file with 1500-byte payload and 40-byte header per packet, compute number of packets and total bytes on wire.