ISRO2016-70

Question

Which network protocol allows hosts to dynamically get a unique IP number on each bootup

• A. DHCP
• B. BOOTP
• C. RARP
• D. ARP

Comments

DHCP or RARP ?

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Why answer to this question is option A?

Which $\textbf{network protocol}$ allows hosts to dynamically get a unique IP number on each bootup

Here it is specifically said about $\text{network protocol}, DHCP and BOOTP are application level protocol.

According to me ans should be RARP

Answer 1

ARP : Address resolution Protocol :-ARP is used to convert Ip address to MAC address .

Points About ARP 

ARP request is Broadcasting 

ARP reply is Unicast

Various case's in which we apply ARP are

When a Host wants to find out the MAC address of another Host

When a Host wants to find out the MAC address of  Router

When a Router wants to find out the MAC address of another Router

When a Router  wants to find out the MAC address of  Host

RARP : Reverse ARP :- it converts the MAC address into Ip address.Where do we actually use this Protocol is Lets consider an example of  college Lab in which mostly Host does not have Hard Disk and once they gets Turned off they forget everything and when they Turned on they don't have Ip address because they can only remember the things which are on the ROM and Mac address is on the NIC Card on Rom but ip address will be present on RAM so that's how we need this Protocol to get the Ip address of the Host which is newely connected to the Network and it has its Mac address with it and with the help of RARP we get the Ip address.So only purpose of RARP is to fetch the Ip address of Host and Configure it .The table used for mapping in RARP is Static means A Mac address is assigned to a particular Ip address. There is nothing called Dynamic here.

Boot P : The main difference between RARP and BootP is BootP is going to run on Application Layer whereas RARP runs on Network Layer In BootP request for asking Ip address comes from Application Layer instead Network Layer.

DHCP : Dynamic Host Configuration Protocol :-  The main difference between DHCP and BootP is the Table which need not be static in case of DHCP .(we create a table in the Process of assigning of Ip address)

DHCP is very Popular and it is used by most of the ISP where ever we don't have private Ip we use DHCP

Answer : it must be DHCP

Answer 2

DHCP(dynamic host configuration protocol)

DHCP gives Ip addresses dynamically to the host whenever it is connected to internet and removes the IP when it is offline.

As well DHCP is backward compatible with BOOTP so it serves IP to the BOOT client machines also( Machine having BOOTP port number inside the OS file) OS of each machine maintains list of all the protocol port number which our system uses.

Answer 3

Its C) RARP. On every bootup host gets IP by using RARP.