Task 11. Fill in the blanks with the proper word from the text 11B

1. The message is ____________into bits by the ________________layer.

2. The ___________ layer confirms the arrival of the packets, logs them in, and calculates the ____________ for each packet.

3. The incoming ___________ are recounted by the network layer for security and billing purposes.

4. The checksum is re-____________by the transport layer which also reassembles the message segments.

5. The parts of the message are held _______________the session layer _____________the message is complete. Then it sends the message to the next _______________________.

6. The message is compressed and ___________________ by the presentation layer.

7. The application layer converts the bits into __________________ characters, and ____________ the data to the correct application.

Task 12. Mark the following statements true or false.

1. Most of the work that an application does to prepare a message for sending over a network is not seen by the user.

2. ASCII is always used to transmit data.

3. The encryption layer compresses the message.

4. The network layer keeps track of how many packets are in each message.

5. The network layer keeps a copy of each packet until it arrives at the next node undamaged.

6. Analogue signals are used on ordinary telephone lines.

7. When a message arrives at its destination, it passes through the same seven network communications layers as when it was sent, but in reverse order.