In this article I describe the ICMP Internet Control Message Protocol in computer network for CCNA exam. ICMP Internet Control Message Protocol is related to internet layer of TCP/IP Suite model. The ICMP Internet Control Message Protocol provides the troubleshooting and testing the connectivity between different devices on a network or internet. ICMP Internet Control Message Protocol provide the facility to check the data flow speed between different devices on network or internet. ICMP Internet Control Message Protocol mostly used to check the network congestion and route of data packet in all networks like TCP/IP network and Cisco Three layered hierarchical network.
ICMP Internet Control Message Protocol does not send any data in the network between devices. ICMP Internet Control Message Protocol used to check the connectivity and data flow speed in the network. All networking devices and endpoint devices of the network can use the ICMP Internet Control Message Protocol. ICMP packets are different from other data packets.
Routing and Routed Protocols provides the connectivity between different networks for data packets flow from one network to another network. A standard routing table is maintained by the routers for data packet flow between different networks.
Before going to learn about ICMP Internet Control Message Protocol in detail, we need to remember the OSI suite and TCP/IP suite model. There are many manufacturer of computer machine in the market. Initially when computers became single user public computer. The computers communicate with only same brand machines. It happens because there was no any fix standard for data transfer between different devices. It is very difficult to make communication with each other when the hardware are of different brands or company. In this article I describe the some basic part of OSI reference layer and TCP/IP Suite model basic concepts in networking with the ICMP Internet Control Message Protocol.
OSI reference model basic concepts
OSI reference model in computer network followed by various vendors to overcome the compatibility problem. After implementation of OSI reference model in computer network, equality maintains by all manufacturer. In 1970 the Open Systems Interconnection (OSI) reference model was created by the International Organisation for Standardisation (ISO). The OSI model was meant to create inter-operable network with different manufactured devices. In this article I describe some layered approach of TCP/IP Suite model basic concepts in computer network. Before understanding the TCP/IP Suite model basic concepts it is necessary to know about the 7 layers of OSI reference model because the basic work of each layer is described in the OSI reference model. You can read the full article related to OSI reference model in computer networking here.
Importance of OSI reference model forICMP Internet Control Message Protocol
Before going to know about the ICMP Internet Control Message Protocol. It is necessary to know the function of layers in OSI model and TCP/IP model. Initially not only hardware but software also not supported for work the different computer brand. It became very difficult for all computer users to working without implementation of OSI reference model in computer network. It is necessary then to make some common protocols for all vendors of computer. Before implementation of OSI reference model in computer network, all vendors implements their own protocols on computer hardware and software.
In networking OSI reference model became helpful. OSI reference model describes the flow of data between nodes in any network. Data from one computer application to another computer application transfer by following some common protocols. The OSI reference layer also become beneficial for troubleshooting the network problems. TCP/IP and Cisco three layered hierarchical model of Cisco became more helpful alongside the OSI reference model.
The Layered Approach in computer network
The Layered approach was the best way to make equality for all computer devices. Layers are not physical but following some protocols. Protocols are for connectivity, connections, data transfer and more. All manufacturer begin to follow the layered approach for OSI reference model in computer network. The OSI reference model change in TCP/IP reference model and later on Cisco three layered hierarchical model. OSI layer architecture have 7 layers. TCP/IP reference model convert these 7 layers into only four layers. After that Cisco three layered hierarchical model converts these 7 layers into three layers. Some layers combined to work in a single layer.
OSI is acronym for open system interconnection. The OSI is a logical reference OSI reference model in computer network. OSI model helps for data flow between different devices and operating systems. All manufacturer used their own architecture before invention of OSI reference model. It was very difficult to establish data communication between different devices. To overcome this problem international organization for standardization (ISO) created the open systems interconnection (OSI) reference model. OSI reference model make data flow possible between different operating system, devices and hardware. Later the OSI model adopted by Cisco as Cisco three layered hierarchical model.
Structure of OSI reference model related to ICMP Internet Control Message Protocol
OSI reference model in computer network consist of 7 layers. These 7 layers further divided into two groups. First 3 layers works for application communication and remaining 4 layers works for data flow. Application, presentation and session layers define the application communication. Transport, network, data link and physical layers define the data flow. Networking protocols works only on last four layers.
TCP/IP Suite model basic concepts forICMP Internet Control Message Protocol
TCP/IP is acronym for Transmission Control Protocol/Internet Protocol (TCP/IP suite model). In this section of the article I describe about TCP/IP suite model basic concepts in detail. TCP/IP suite model is a reference model like OSI layers. Instead of 7 layers of OSI reference model. TCP/IP suite model consist only four layer. All seven layers are merged into four layers only. TCP/IP suite model was designed and implemented by Department of Defence (DoD). TCP/IP developed to preserve data integrity. The main purpose to develop the TCP/IP is to provide security in the network. A lots of protocols works on each layer to provide a secure network.
It is necessary to understood the protocols used in TCP/IP Suite model basic concepts. IP addressing play an important role in TCP/IP Suite model basic concepts. By using the IP address and subnet masking broadcast domain breaks. It will improve the performance of the network. Breaking broadcast domain increase the data flow speed. Here IP stands for IPV4 only. We ignore the IPV6 for some time in this article. It will make it easy to understand the TCP/IP Suite model basic concepts.
A snap of TCP/IP Suite model basic concepts
In the decade of 1970’s TCP/IP suite model developed by DoD. In the initial stage TCP/IP suite model divided into two segments TCP and IP. Later its name registered with combined name of TCP and IP like TCP/IP model. ARPA, the Advanced Research Projects Agency of DoD officially authorised to use TCP/IP suite model. TCP/IP model was working well so it was adopted by many organisations. In today scenario it is mostly using reference model for networking. Internet is the best example of using TCP/IP.
Process or Application layer of DoD model in TCP/IP Suite model
This is the first layer of TCP/IP of DoD model. It is combination of top three layers of OSI reference model. The functions of Application layer, presentation layer and session layer in OSI model works in single layer process layer. This layer supports the point to point communication and controls the user interface. The data encryption and decryption also done at this layer. Example of some protocols functions at this layer are TLS Transport Layer Security, FTP, LPD, TFTP, SMTP.
Transport layer of DoD model in TCP/IP Suite model
Transport layer of TCP/IP is same as the Transport layer of OSI reference model. It supports the TCP and UDP protocol. This protocol converts the main data segment into packets and transport to the internet layer. The responsibility of Transport layer is to combine the segments and built the data. The data should be reconstruct in its real form. Transport layer is also responsible for creating end-to-end communication between sender and receiver. This layer ensure the delivery of segment in sequence at the receiving device. This property maintains the data integrity.
Internet layer of DoD model in TCP/IP Suite model
Internet layer of TCP/IP is similar to the network layer of OSI reference model. Routing protocols functions on Internet layer of TCP/IP model. Addressing and filtering of packets is main responsibility of Internet layer of TCP/IP model. This layer provides the transmission of packet in the whole network. Some example of protocols functions on internet layer are ICMP, ARP and IP.
Link layer of DoD model in TCP/IP Suite model
Link layer is the least layer of TCP/IP. Basically link layer is combination of data link and physical layer of OSI reference model. Link layer is also known as Network Access layer. It works on MAC address based data transmission. Link layer handles the frame and bits. It receive the bits and constructs frame from merging bits in a sequence. In case of any bit is missing this layer request to re transmit the bits. Ethernet, FDDI, WAP etc functions on this layer. There is no any preset specification for link layer. Link layer functions on any type of existing media.
ICMP Internet Control Message Protocol
ICMP is acronym for Internet Control Message Protocol. ICMP Internet Control Message Protocol is an internet layer protocol in TCP/IP model. The ICMP protocol provides error reporting, troubleshooting of network devices in a network. ICMP works with IP protocol, as IP protocol is a connectionless and unreliable protocol. ICMP is mostly used by ping and traceroute command. Data lost reporting is main responsibility of ICMP protocol. Ping command show the data transmitted and received quantity. Counting of lost packets monitored and reported by the ICMP protocol to all device in a network.
ICMP is a part of IP protocol. IP protocol use ICMP protocol to send the error message to network devices. ICMP use IP protocol for transporting message. So, both IP and ICMP protocol are complements to each other in a network.
Some errors encountered by ICMP Internet Control Message Protocol
Time Exceeded error. As suggested by this message text, this error shows the time exceeded in data delivery. This message generated in two conditions. The first condition is when a router is running out of space and take so much time to deliver the data packets. Another reason of this message is any host is not receiving the datagrams to reassemble the packets.
Host is reachable in this condition. Host unreachable is another error countered by ICMP Internet Control Message Protocol. Route Redirect error. This error occurs when a host sent wrong addressee to a router. Generally, a host send datagram to a router who have the route of its destination. In case router doesn’t have the route for a datagram packet then Route Redirect error occurs. Host Unreachable. When the destination not found for delivery of a datagram host unreachable message floated.
Echo request and Echo reply in ICMP Internet Control Message Protocol
Echo request and Echo reply used to check the connectivity between two hosts in a network. PING command is best example of Echo request and Echo reply message. Ping command is used to check the connectivity between two hosts. Host A wants to check the connectivity with host B. User will run Ping command in host A for host B. host A sent 4 packets in the network with addressee header of host B. host A send Echo request in the network. If Host B is connected in network and ICMP enable on its firewall, then Host B receive the Echo request and send Echo reply to host A. it is a complete cycle of echo request and echo reply in a network.
Function of ICMP Internet Control Message Protocol
General errors always generate in a network. ICMP Internet Control Message Protocol is responsible to monitor these errors and info to related networking device. network devices like routers generate error message and send to source IP address. All networking device are capable to send, receive and process the ICMP Internet Control Message Protocol. Suppose a gate way is out of reach to router. A host in the network send a packet to the destination which is away from the gateway. Router will generate an error message host is not reachable and send to the intended host. This process is done by a set of rules, which followed by ICMP Internet Control Message Protocol. For IPv4 addressing system ICMP4 functions for error reporting. For IPv6 ICMP6 functions for error reporting.
In this article I describe the ICMP Internet Control Message Protocol in computer network for CCNA Exam. I hope you found this article helpful for any query or suggestions you may drop a comment below or contact us. Your suggestions are always welcome by us.
