Describing the packet switching process step by step

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Quick Questions

Shade in the A or B circle for each question.

1. What is the FIRST step of packet switching?

A The data is split into packets and each packet is numbered

B The packets are reordered at the destination

2. Who chooses the route each packet takes?

A A router, for each packet separately

B The sender picks one route for all packets

3. Packets from the same message are sent across a network. What can happen?

A They can take different routes and arrive out of order

B They must always arrive in the order they were sent

4. When is the data put back into order at the destination?

A As soon as the first packet arrives

B Once the last packet has arrived

5. The message HELLO is split into packets 1:HE, 2:LL, 3:O. They arrive as 2, 3, 1. What does the destination do?

A Joins them in the order they arrived to get LLOHE

B Uses the packet numbers to reorder them as 1, 2, 3 to get HELLO

Match the Pairs

Draw a line connecting each item on the left to its match on the right.

Left column		Right column
1Step 1: Split the message into packets and number them		AThe sender breaks the data into small packets and gives each one a packet number in its header
2Step 2: Each router chooses the route for each packet		BPackets arrive: 3, 1, 4, 2
3Packets can arrive at the destination out of order because they took different routes of different lengths		CReorder 3, 1, 4, 2 into 1, 2, 3, 4 = HELLO
4When the last packet arrives, the packets are put back in order using their packet numbers to rebuild the message		DThe packets are reordered once the last packet has arrived, not the first. Packets may still be missing until then.
5Step 1: Send the whole message as one packet with no numbers		ERouters on the network decide which path every packet takes, so packets from one message can travel different routes
6Step 4: Reorder the packets as soon as the first packet arrives		FPacket switching starts by splitting the data into several packets and numbering them. Without numbers the destination cannot reorder them.

Definitions

packet switching steps

Fill in the Blanks

Complete each line of code by filling in the missing parts.

Step 1: Split the data into _______ Step 2: Number each packet

Step 1: Number each packet Step 2: A ______ picks each packet's route

Step 3: Packets may arrive out of _____

Step 4: Wait for the ____ packet to arrive

Packets arrive as 2, 1, 3 Reordered by packet ______: 1, 2, 3

Spot the Error

Shade in the letter of the line that contains an error.

Question 1

A JOIN message INTO packets

B NUMBER each packet 1,2,3

C ROUTER picks route per packet

D REORDER at destination

Question 2

A SPLIT data INTO packets

B NUMBER each packet

C ROUTER uses one route for all

D REORDER at destination

Question 3

A SPLIT data INTO packets

B NUMBER each packet

C ROUTERS pick each route

D PACKETS always arrive in order

E REORDER by packet number

Question 4

A message = HELLO

B split into HE, LL, O

C number them 1, 1, 1

D router picks route for each

Question 5

A packet 3 arrives first

B packet 1 arrives second

C packet 2 arrives third

D reorder by arrival time

E message rebuilt: 1, 2, 3

Answer Key

Describing the packet switching process step by step

Section A: Quick Questions

A — The data is split into packets and each packet is numbered

A — A router, for each packet separately

A — They can take different routes and arrive out of order

B — Once the last packet has arrived

B — Uses the packet numbers to reorder them as 1, 2, 3 to get HELLO

Section B: Match the Pairs

Step 1: Split the message into packets and number them → The sender breaks the data into small packets and gives each one a packet number in its header

Step 2: Each router chooses the route for each packet → Routers on the network decide which path every packet takes, so packets from one message can travel different routes

Packets can arrive at the destination out of order because they took different routes of different lengths → Packets arrive: 3, 1, 4, 2

When the last packet arrives, the packets are put back in order using their packet numbers to rebuild the message → Reorder 3, 1, 4, 2 into 1, 2, 3, 4 = HELLO

Step 1: Send the whole message as one packet with no numbers → Packet switching starts by splitting the data into several packets and numbering them. Without numbers the destination cannot reorder them.

Step 4: Reorder the packets as soon as the first packet arrives → The packets are reordered once the last packet has arrived, not the first. Packets may still be missing until then.

Section C: Definitions

packet switching steps — Data is split into numbered packets, routers pick each packet's route, packets may arrive out of order, then they are reordered to rebuild the data once the last packet arrives.

Section D: Fill in the Blanks

Step 1: Split the data into packets
Step 2: Number each packet

Step 1: Number each packet
Step 2: A router picks each packet's route

Step 3: Packets may arrive out of order

Step 4: Wait for the last packet to arrive

Packets arrive as 2, 1, 3
Reordered by packet number: 1, 2, 3

Section E: Spot the Error

A — The first step of packet switching is to split the data into packets, not join it. The line should be SPLIT message INTO packets. Joining (reordering) happens last, at the destination.

C — A router chooses the route for each packet separately, so packets can take different routes. The line should be ROUTER picks route per packet.

D — Packets can take different routes with different delays, so they may arrive out of order. The line should say they may arrive unordered, which is why reordering is needed.

C — Each packet needs its own number so the destination can put them back in order. The numbers should be 1, 2, 3, not the same number for every packet.

D — Packets are reordered using the packet number in the header, not by when they arrived. Arrival order may be wrong because of different routes. It should be reorder by packet number.