ISRO 2008- ECE Switch and Hub

Question

Difference between a switch and Hub

(a) Both are same

(b) Switch avoids flooding

(c) Hub avoids broadcast

(d) None of the above

Answer 1

answer is B) Switch avoids flooding

Comments

No. If the destination mac address of the packet is not in the L2 forwarding table of the switch, it will simply flood the packet onto all of the ports in VLAN to which the packet came to . So there is flooding in switch.

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but option asks who "avoids" flooding.

Hub never avoids flooding while Switch always avoids flooding if an entry for destination is in switching table.

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In that case of having destination mac address in L2 forwarding table, it will not flood. While reading options, I felt it is like a more generalized case and thought that option says switch completely avoids flooding no matter which case . flooding is like a basic characteristic of switch.

but option asks who "avoids" flooding.

why did u say this ?

Answer 2

I think the basic difference between switches and hub that switches maintain something is known as Forwarding table.

Forwarding table is nothing but the entries of mac Addresses connected to that particular network by which switches decide in which computer they have to send the data in order to avoid broadcasting the frames.

while Hubs does not maintain forwarding table, they are known as Broadcasting devices.

.So, B)  Switches avoids flooding will be answer