Layer 4 (Transport) (obj 1.1)

Question 1

Transport Layer (end to end or host to host layer)

Answer 1

Dividing line between the upper layers and the lower layers of the OSI model.

Question 2

Transmission Control Protocol (TCP)

Answer 2

Connectin-oriented protocol that is a reliable way to transport segments accross the network.

Question 3

User Diagram Protocol (UDP)

Answer 3

Connectionless protocol that is an unreliable way to transport segments accross the network.

Question 4

Windowing

Answer 4

Allows the clients to adjust the amount of data in each segment.

Question 5

Buffering

Answer 5

Occurs when devices allocate memory to store segments if bandwidth is not readily avaliable.

Question 6

What is a main function of Layer 4

Answer 6

identifies each type of network application by assigning it a port number.

Question 7

What data type is used at Layer 4

Answer 7

Layer 4 encapsulates data into layer 4 PDU’s called segments. These are tagged with the applications port number and then passed to the network layer for delivery.

Question 8

Does layer 4 have Reliable data delivery?

Answer 8

Yes, The Transport layer can implement reliable data delivery mechanisms, should the application require it.

Reliable delivery means that any lost or damaged packets are resent.

Question 9

What devices work at layer 4

Answer 9

1. Multilayer switches (usually working as load balancers)
2. IDS/IPS advanced firewalls