Question

Define and explain the significance of the following terms.

Destination Unreachable packets

ICMP Router Solicitation

Network Congestion

Provide a detailed description of the purpose and usage of the Internet Control Message Protocol (ICMP) in the framework of an IP network.

Provide an example of the practical application of the ping and tracert commands.

Briefly describe the following ICMPv6 message types: Router Solicitation, Router Advertisement, and Redirect.

Briefly describe the following ICMPv6 message types: Neighbor Solicitation and Neighbor Advertisement.

What is the numeric range of ICMPv6 error messages?

What is the numeric range of ICMPv6 informational messages?

What are the processes involved with Neighbor Discovery?

Answer 1

Destination Unreachable packets: When the destination is unreachable for some reason, the gateway or the host generates the ICMP packet, which is sent to the client. By looking over this packet, the client can understand that destination is unreachable currently.Without this, client may keep sending the packet forever and waiting for acknowledgement in case of TCP.

ICMP Router Solicitation: This packet is sent from a computer to any router to tell them to advertise their presence in the network. This packet is important, otherwise hosts or other routers won't know that there is another router in the network.

Network Congestion: It is the reduced quality of service that happens when any number of nodes or links may be carrying data more than their capacities. As congestion increases, delay decreases and number of re-transmission increases. Two algorithms are currently in practice to control network congestion: 1)Leaky Bucket Algorithm 2) Token Bucket Algorithm

Q: Provide a detailed description of the purpose and usage of the Internet Control Message Protocol (ICMP) in the framework of an IP network.

A: It is an error control mechanism for IP network. It is used for reporting errors and management queries. It is a support mechanism used by the routers. There are several types of ICMP packets that deal with different types of problems, like,

i) Source quench message : This packet is sent to tell the source to slow down the sending rate.

ii) Parameter problem : Whenever a packet comes to the router, it calculates the checksum. If the calculated checksum is not equal to the header checksum, then there is a parameter problem and ICMP packet is sent to the source with error "Parameter problem".

iii) Time exceeded message : When time to live field in the packet goes to zero, the router drops the packet and send an ICMP packet to the source IP extracted from the packet. It comes handy when packets get lost in the network.