GATE CSE 2021 Set 1 | Question: 8

Question

Consider the following two statements.

• $S_1$: Destination $\text{MAC}$ address of an $\text{ARP}$ reply is a broadcast address.
• $S_2$: Destination $\text{MAC}$ address of an $\text{ARP}$ request is a broadcast address.

Which one of the following choices is correct?

• A. Both $S_1$ and $S_2$ are true
• B. $S_1$ is true and $S_2$ is false
• C. $S_1$ is false and $S_2$ is true
• D. Both $S_1$ and $S_2$ are false

Comments

I interpreted this question in test as ARP is address resolution protocol so if perticular systemwant to get ip address which is linked to perticular link like https://gateoverflow.in  then it broadcast to all the servers which do the work of resolve this link into ip address by using ARP protocol and after resolution when server sent ip addr then its src is fixed (means who sended the request ) so server reply willl contain the exact mac address of that system 

so statement 1 is false and 2 is true

Answer 1

In ARP, source broadcasts an ARP request to all devices in local subnet.

The destination which has the matching IP address then sends an ARP response which includes the MAC address of the source and hence is a unicast message.

Option (C) S1 is false and S2 is true

Answer 2

Destination MAC address of an ARP request is broadcast address  (for find destination mac address )

But reply is not broadcast (destination send its mac address to sender only)

 

So C is correct answer first false second true.

Answer 3

ANS IS C, S1 IS FALSE AND S2 IS TRUE

Answer 4

Source 1 (Ram) sends a message to Source 2  (Shyam)

now when the packet is in the router using ARP , will act like listen everyone  (broadcasting) if you are Shyam then raise your hand then Shyam will reply by raising hand  then the packet is received by Source 2