Neighbour Discovery Protocols


Neigbour Discovery Protocols provides directly connected devices to discover and collect information about each other. Network devices can provide directly connected neighbour device’s identification, configuration and any capabilities. Neighbour Discovery Protocols work on Layer 2.



There are different Neigbour Discovery Protocols for different vendors. Generally they are refer this protocol like “vendor” discovery protocol. For example Nortel Discovery Protocol (NTP) . Nortel is the Vendor of this protocol. Cisco Discovery Protocol (CDP) . Cisco is teh vendor of CDP. Beside these, there is a standard neighbour discovery protocol, LLDP ( Link Layer Discovery Protocol) .


Network Neighbour Discovery
Network Neighbour Discovery


There a number of discovery protocols but in this article we will discuss two of them. The standard neighbour discovery protocol LLDP (neighbour Discovery Protocol) and the Cisco proprietary neighbour discovery protocol, CDP (Cisco Discovery Protocol). We will also talk about LLDP-MED (Link Layer Discovery Protocol – Media Endpoint Discovery) and we will make a comparison of these protocols.


Neighbour Discovery Protocols, Network Neighbour Discovery
Neighbour Discovery Protocols



For IPv6, there is also a neighbour discovery protocol also called Neighbour Discovery Protocol (NDP). This is a standard based protocol also. We will discussed this protocol detailly in the following articles.


Over times, different vendor specific neighbour discovery protocols become too mush and a standardization become necessary. So, to make this neighbour discovery standard, LLDP is developed.



Being a standard protocol has both advantages and disadvantages. For example, Cisco has CDP and CDP has some advantages over LLDP. On the other hand, you can discover only Cisco devices with CDP. Beside, LDDP has another advanatges. We will cover all these advantages and disadvantages on CDP and LLDP lessons. We will compare these two important layer 2 protocols.


The neighbour discovery protocols provide a view of the network and this important data, is used in different are areas. So, in which applications, discovery protocol datas are used? In the Network management systems, VLAN configurations, inventory and emergency services are the areas that, these datas are mostly used.


Here, we have learn the basics of this lesson. In the following lessons, we will talk about the neighbour discovery protocols detailly. If you would like to learn CDP, LLDP and more on neighbour discovery, you can view the other lessons. In these lessons, we will learn both theorical details of these protocols and the How to configure these protocols on network devices. You can view CDP Configuration on Packet Tracerlesson as an example.


Lesson tags: CDP, neighbor discovery, lldp
Back to: CCNA 200-301 > Neighbor Discovery

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CCNA 200-301