9) (25 points) Consider the figure below (Fig.4), which shows the arrival of 6 messages for transmission at different mu

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9 25 Points Consider The Figure Below Fig 4 Which Shows The Arrival Of 6 Messages For Transmission At Different Mu 1 (292.95 KiB) Viewed 53 times

9) (25 points) Consider the figure below (Fig.4), which shows the arrival of 6 messages for transmission at different multiple access wireless nodes at times t = <0.8, 1.2, 2.9, 3.1, 4.3, 4.6> and each transmission requires exactly one-time unit. ² t=0.0 t=1.0 t=2.0 t=3.0 t=4.0 t=5.0 Fig.4. Transmission times of different multiple access nodes sharing a transmission medium a) (5 points) Aloha a.1) Suppose all nodes are implementing the Aloha protocol. For each message, indicate the time at which each transmission begins. Separate each value with a comma and no spaces. a.2) Which messages transmit successfully? Write your answer as a comma separated list with no spaces using the messages' numbers b) (5 points) Slotted Aloha b.1) Suppose all nodes are implementing the Slotted Aloha protocol. For each message, indicate the time at which each transmission begins. Separate each value with a comma and no spaces. b.2) Which messages transmit successfully? Write your answer as a comma separated list with no spaces using the messages' numbers c) (5 points) CSMA c.1) Suppose all nodes are implementing Carrier Sense Multiple Access (CSMA), but without collision detection. Suppose that the time from when a message transmission begins until it is beginning to be received at other nodes is 0.4 time units. (Thus if a node begins transmitting a message at t=2.0 and transmits that message until t=3.0, then any node performing carrier sensing in the interval [2.4, 3.4] will sense the channel busy.) For each message, indicate the time at which each message transmission begins, or indicate that message transmission does not begin due to a channel that is sensed busy when that message arrives. Separate each value with a comma and no spaces, and if the channel is sensed busy, substitute it with 's' c.2) Which messages transmitted successfully? Write your answer as a comma separated list with no spaces using the messages' numbers d) (10 points) CSMA/CD d.1) Suppose all nodes are implementing Carrier Sense Multiple Access (CSMA), with collision detection (CSMA/CD). Suppose that the time from when a message transmission begins until it is beginning to be received at other nodes is 0.4 time units, and assume that a node can stop transmission instantaneously when a message collision is detected. (Thus if a node begins transmitting a message at t=2.0 and transmits that message until t-3.0, then any node performing carrier sensing in the interval [2.4, 3.4] will sense the channel busy.) For each message, indicate the time at which each message transmission begins, or indicate that message transmission does not begin due to a channel that is sensed busy when that message arrives. Separate each value with a comma and no spaces, and if the channel is sensed busy, substitute it with 's d.2) Which messages transmitted successfully? Write your answer as a comma separated list with no spaces using the messages' numbers d.3) At what time did each message stop transmitting due to a collision. Write your answer as a comma separated list with no spaces using the messages' numbers in order, and if a message didn't stop, write 'x' for that message