<h3><u>CSMA/CD Protocol:
</u></h3>
Carrier sensing can transmit the data at anytime only the condition is before sending the data sense carrier if the carrier is free then send the data.
But the problem is the standing at one end of channel, we can’t send the entire carrier. Because of this 2 stations can transmit the data (use the channel) at the same time resulting in collisions.
There are no acknowledgement to detect collisions, It's stations responsibility to detect whether its data is falling into collisions or not.
<u>Example:
</u>
, at time t = 10.00 AM, A starts, 10:59:59 AM B starts at time 11:00 AM collision starts.
12:00 AM A will see collisions
Pocket Size to detect the collision.
![\begin{aligned}&T_{t} \geq 2 T_{P}\\&\frac{L}{B} \geq 2 T_{P}\\&L \geq 2 \times T_{P} \times B\end{aligned}](https://tex.z-dn.net/?f=%5Cbegin%7Baligned%7D%26T_%7Bt%7D%20%5Cgeq%202%20T_%7BP%7D%5C%5C%26%5Cfrac%7BL%7D%7BB%7D%20%5Cgeq%202%20T_%7BP%7D%5C%5C%26L%20%5Cgeq%202%20%5Ctimes%20T_%7BP%7D%20%5Ctimes%20B%5Cend%7Baligned%7D)
CSMA/CD is widely used in Ethernet.
<u>Efficiency of CSMA/CD:</u>
- In the previous example we have seen that in worst case
time require to detect a collision.
- There could be many collisions may happen before a successful completion of transmission of a packet.
We are given number of collisions (contentions slots)=4.
Distance = 1km = 1000m
![\begin{aligned}&\text { Speed }=2 \times 10^{8} \mathrm{m} / \mathrm{sec}\\ &T_{P}=\frac{1000}{2 \times 10^{8}}=(0.5) \times 10^{-5}=5 \times 10^{-6}\\ &T_{t}=5 \mu \mathrm{sec}\end{aligned}](https://tex.z-dn.net/?f=%5Cbegin%7Baligned%7D%26%5Ctext%20%7B%20Speed%20%7D%3D2%20%5Ctimes%2010%5E%7B8%7D%20%5Cmathrm%7Bm%7D%20%2F%20%5Cmathrm%7Bsec%7D%5C%5C%20%26T_%7BP%7D%3D%5Cfrac%7B1000%7D%7B2%20%5Ctimes%2010%5E%7B8%7D%7D%3D%280.5%29%20%5Ctimes%2010%5E%7B-5%7D%3D5%20%5Ctimes%2010%5E%7B-6%7D%5C%5C%20%26T_%7Bt%7D%3D5%20%5Cmu%20%5Cmathrm%7Bsec%7D%5Cend%7Baligned%7D)
Answer:
7.94 ft^3/ s.
Explanation:
So, we are given that the '''model will be 1/6 scale (the modeled valve will be 1/6 the size of the prototype valve)'' and the prototype flow rate is to be 700 ft3 /s. Then, we are asked to look for or calculate or determine the value for the model flow rate.
Note that we are to use Reynolds scaling for the velocity as par the instruction from the question above.
Therefore; kp/ks = 1/6.
Hs= 700 ft3 /s and the formula for the Reynolds scaling => Hp/Hs = (kp/ks)^2.5.
Reynolds scaling==> Hp/ 700 = (1/6)^2.5.
= 7.94 ft^3/ s
Independent auto lots usually have <u>higher</u> finance rates than dealerships
<u>Explanation:</u>
The finance rates that are charged by the dealers are lower than the finance charges that are charged by the independent auto. In case if you are getting financed through dealerships, you can also negotiate with them to charge finance rates and lower the charges of the finance.
But this negotiation and lowering of the finance rates is not possible with the independent auto lots and thus they charge higher rates compared to the dealerships.
Answer:
4.modifying a building to achieve an entirely new purpose