GATE | GATE CS Mock 2018 | Set 2 | Question 23
IPv4 addressing system already gives information about network and host. Along with the Internet Protocol address of host, subnet mask is also needed by the routers inorder to direct the packet to intended network. Host doesn’t redirect packets, then Why does host need subnet mask ?
(A) Host need subnet mask for ANDing process inorder to know own network.
(B) To get the IP address of destination host
(C) To know if intended packet is supposed to send to router or not.
(D) To resolve the logical address from DNS server.
Explanation: We know Subnet mask is needed by routers (stored in routing table) inorder to direct the packet to intended network. But how will host know whether the packet belongs to its own network, whether to send the packet to router or not. For this reason, even host needs the Subnet mask.
Therefore, option (C) is correct.
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