TCS Papers: Sample Questions 228 - 229 of 502

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Question number: 228

» Basic CS » Networks

Essay Question▾

Describe in Detail

What is ICMP?


  • Also known as RFC

  • Internet Control Message Protocol (ICMP) is a TCP/IP network layer protocol providing troubleshooting, control, and error message services.

  • ICMP message is created as a result of errors in an IP datagram or for diagnostic routing purposes.

  • ICMP message is encapsulated directly within a single IP datagram and reports errors in the processing of datagram’s.

  • ICMP uses IP as if ICMP were a higher-level protocol.

  • Used in operating systems for networked computers for transmitting error messages- Used by hosts and gateways to send notification of datagram problems back to the sender

  • Uses the echo test & reply to find whether a destination is reachable and responding.

  • These errors are reported to the originating datagram’s source IP address.

  • ICMP for Internet Protocol version is called ICMPv4 and for Internet Protocol version is called ICMPv6.

  • ICMP is an integral part of IP and must be implemented by every IP module.

  • Note that ICMP reports some errors, but does not make IP reliable. Datagram’s may still be undelivered without any report on their loss. Reliability must be implemented by the higher-level protocols that use IP.

ICMP tunneling technique

ICMP Tunneling Technique

ICMP tunneling technique

Question number: 229

» Basic CS » Networks

Essay Question▾

Describe in Detail

What is difference between ARP and RARP?


Table of Difference between ARP and RARP

Table of Difference between ARP and RARP



ARP means address resolution protocol.

RARP means reverse address resolution protocol.

Associates the bit IP address with the bit physical address, used by a host or a router to find the physical address of another host on its network by sending a ARP query packet that includes the IP address of the receiver.

The reverse address resolution protocol (RARP) allows a host to discover its Internet address when it knows only its physical address.

Nodes use ARP broadcast in LAN by using broadcast MAC address

RARP uses broadcast IP address.

Maps IP address of node to its MAC address

Maps bit MAC address to IP address.

Used by host or router to find physical address of another host/router in LAN.

Used by thin clients with limited facilities.

Local host maintains ARP table.

RARP server maintains RARP table.

ARP reply is used to update ARP table.

RARP reply is used to configure IP address in local host.