The ICMP stands for Internet Control Message Protocol. It is a network layer protocol. It is used for error handling in the network layer, and it is primarily used on network devices such as routers. As different types of errors can exist in the network layer, so ICMP can be used to report these errors and to debug those errors.

It is designed to overcome the following problems with IP protocols:

1.No error reporting/correction  mechanism

2. Lacks a mechanism for queries

Position of ICMP in the network layer

The Internet Group Management Protocol (IGMP) is a protocol that allows several devices to share one IP address so they can all receive the same data. IGMP is a network layer protocol used to set up multicasting on networks that use the Internet Protocol version 4 (IPv4).

The ICMP messages are usually divided into two categories:

Error-reporting messages

• The error-reporting message means that the router encounters a problem when it processes an IP packet then reports a message.

Query messages

• The query messages are those messages that help the host to get the specific information of another host. For example, suppose there are a client and a server, and the client wants to know whether the server is live or not, then it sends the ICMP message to the server.