Original subtitles

Now there was other issue with 10base2, the first issue is cable length

the longer the cable the greater the signal degradation was.

In other words as your cable increase in length the more likely it was

that one host signal wouldn�t be received by another host.

The host on one side of the cable might send the signal

but because of degradation a host at the other end of the cable

may not be able to receive or interpret the signal.

Another problem is cable breaks.

A cable break at any point would cause the entire network to fail. 10

So if someone accidentally broke the cable at this point the whole network would fail. 11

Host A cannot communicate with other devices in the network. 12

those devices cannot communicate with host A 13

However because of this cable break there�s no terminator on the cable. 14

The cable is also damaged, so what happens is signals get reflected 15

D might send a signal to C but it�s going to continue across the cable 16

and then it�s going to be reflected back causing collisions on the network, so this 17

network wasn�t very robust and that cable breaks to bring down the entire network. 18

Now it gets worst, 10base2 implies 10Mbps Ethernet however, this is not 10Mbps for 19

each device it's 10Mbps shared between all devices on that segment. 20

In addition because of collisions you can only use between 30 and 40%. 21

So you are only get 30 to 40% utilization. 22

Collisions increased dramatically above that utilization 23

so a conservative figure would be 30% utilization 24

that means 10Mbps would be shared between all devices on that segment. 25

So in this case we have 4 devices 26

so that means the 10Mbps divided by 4 devices times 30% (10/4*30%) 27

only gives you 0.75Mbps and not 10Mbps per device. 28

This is not ideal because the bandwidth available to your PC 29

is very low especially in a large network. 30

So as more devices are added to the network 31

the bandwidth available to each devices decreased 32

this is also known as a single collision domain 33

in other words, if a collision takes place at any point on the network 34

all devices in this network are affected by that collision and would need to back off.