In this article I describe the NDP Neighbor Discovery Protocol in computer network for CCNA exam. NDP Neighbor Discovery Protocol is related to Link layer of TCP/IP Suite model. NDP Neighbor Discovery Protocol works with IPv6 address system in a network. IPv6 address system is advance version of IPv4. In IPv4 address system ARP and RARP protocols were used at link layer of TCP/IP suite model. NDP Neighbor Discovery Protocol is actually an advance version of ARP protocol for IPv6. The NDP Neighbor Discovery Protocol find the nearby routers and keep the database of all network devices update so the data packets can be forwarded to correct destination in the network.
Before going to learn about NDP Neighbor Discovery Protocolin detail, it became helpful 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 NDP Neighbor Discovery 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 Organization for Standardization (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 for NDP Neighbor Discovery Protocol
Before going to know about the NDP Neighbor Discovery Protocol at link layer. 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 organisation for standardisation (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 NDP Neighbor Discovery 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 for NDP Neighbor Discovery 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.
NDP Neighbor Discovery Protocol Explained in brief
NDP Neighbor Discovery Protocol operates on the link layer of TCP/IP suite model and data link layer in the OSI model. The function of NDP Neighbor Discovery Protocol is to resolve the physical address relates to an IP address of a device. Router advertise the NDP Neighbor Discovery Protocol to update all networking devices in the network. The broadcasting became useful for forwarding the data packets in the network. The data transmission became more efficient and relieable via using the NDP Neighbor Discovery Protocol at layer 2 of TCP/IP suite model in the network or internet.
The NDP Neighbor Discovery Protocol is a link layer protocol in TCP/IP model. NDP Neighbor Discovery Protocol is a part of internet protocol IPv6. NDP protocol works just like ARP and ICMP in IPv4 internet protocol suite. IETF Internet Engineering Task Force develop the NDP Neighbor Discovery Protocol for IPv6. The information required for internet collected by NDP Neighbor Discovery Protocol. The information are gateway, DNS etc. NDP Neighbour Discovery Protocol do function for Ipv6. The functions are similer to ARP and ICMP in internet protocol IPv4.
Functions of NDP Neighbor Discovery Protocol
NDP use some terms to perform the task. These terms are router solicitation, router advertisement, neighbor solicitation, neighbor advertisement, and network redirects.
End devices connected in the LAN or internet search for router next hop. Router Solicitation message provides the information of router connected with the end device. It is just request and respond function in the network. Devices request for router information and router respond with information to the devices.
Router advertise to nearest link about the status of it. Whether router is live or not. This information updated in all the routers and devices immediately. Time interval of such advertisement are pre defined.
Devices send a request to neighbour to get the status of neighbour device. Neighbour solicitation message inform about the neighbour device readability. A reply sent to the device that the link is up and device is ready for communication.
Just like routers device advertise their status in the network. The neighbour advertisement is the reply of neighbour solicitation message. By advertisement every device update the status of neighbour in the network.
Benefits of NDP Neighbor Discovery Protocol
NDP protocol provides smooth function of a network. Each device know the router connected to its link. DHCP provides the address auto-configuration. Advertisement helpful for mapping the MAC address with IP address of a device. This will update the table in all devices and switch in the network. Discovery of next hop router become easy for devices. Network devices check whether the duplicate address allotted to devices in the network.
In this article I describe the NDP Neighbor Discovery 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.
