part 1: List down the services provided by the data link layer. part 2: Suppose there are 4 nodes sharing a broadcast channel using TDMA protocol. Suppose at time t=0: Node 1 has three frames to...

part 1:

List down the services provided by the data link layer.

part 2:

Suppose there are 4 nodes sharing a broadcast channel using TDMA protocol. Suppose at time t=0:

Node 1 has three frames to transmit,

 Node 2 has two frames to transmit,

 Node 3 has no frame,

Node 4 has four frames to transmit.

The length of time slot is 2 seconds whereas time needed to transmit one frame is 1 second.  Explain how TDMA will work and how much time will be taken to transmit all of these frames?

part 3:

Do we need to use multiple access protocol in following cases?

1. Lab computers connected to a layer 2 switch through Ethernet cables (star topology)


2. Two computers in an Ethernet bus topology


3. Your laptop is connected to BIIT network through a WiFi link

Answer, yes or no and then justify your answer. Also, mention the name of the multiple access protocol if your answer is yes.

part 4:

Explain the difference between ALOHA and Slotted ALOHA, which one performs better and why?

part 5

What do we mean by bit time while computing Ethernet (CSMA/CD) backoff time?

part 6:

Suppose there is a shared link (e.g. Ethernet bus) of 1 Mbps. How much time is needed (in microseconds) to transmit a 1000 bits long frame on this link?

Suppose value of K is 1 (Ethernet CSMA/CD), compute backoff time when link capacity (data rate) is:

1. 10 kbps


2. 100 kbps