Global Knowledge
It can be difficult for businesses to manage the huge amounts of data flowing through modern networks. Businesses are constantly restructuring and expanding their networks. It is important that clients and servers communicate with one another, especially as new machines and processes can be added at any time.
Next Hop Resolution Protocol allows businesses and clients to create a way for next hop servers to communicate directly with one another, without the need to use a central hub. This eliminates potential bottlenecks.
What are the Next Hop Resolution Protocol Commands?
Next Hop Resolution Protocol allows Next Hop Clients (NHCs), to dynamically register with Next Hop Servers. Dynamic Multipoint Virtual Private Network design, (DMVPN), makes NHC the spoke router and NHS the hub router. Once all clients are registered, spoke routers can find other spoke routers within the same non-broadcast multiaccess network (NBMA).
Another way to see it, is through the prism a different type of communication: telephone conversations.
A network with NHRP is similar to a small town that has everyone having a cellphone. A network that routes all communications between clients and servers to their internet service provider (ISP) is analogous to a small town with an older switchboard operator.
There is no way to have too many people make calls at once if there is a switchboard-centered telephone network in a city. All the cables that must be unplugged, plugged and unplugged can quickly overwhelm a switchboard operator. The volume of requests and forwards your ISP receives can also cause it to become overwhelmed.
Your network functions more like an isolated community with cell phone service. Clients can communicate directly with each other because they have each other’s “numbers”. In this example, the “numbers”, which are the public IP addresses for each client in next hop networks, are the “numbers”.
You don’t have to send huge amounts of data through the hub of an ISP. NHRP allows clients to communicate with servers directly using their public IP addresses.
Also read: Building towards your 99.999% Availability Goal using a First Hop Redundancy Protocol
The Problem NHRP was Designed to Solve
NHRP was first introduced in NBMA networks such as Frame-Relay and Asynchronous Transfer Mode (ATM). NBMA networks usually have all devices and routers connected via the same IPv4 network. Multicasts and broadcasts are not as effective as Ethernet networks because legacy NBMA networks use Layer 2 WAN Implementations that have no routing within the WAN.
To reach another spoke, spoke routers must route through the NBMA network. This restriction could cause a bandwidth bottleneck at the hub router.
Next: Policy-Based Routing. What is it? How can it be used effectively?
Instead of NHRP, why not use a full mesh topology?
One solution is to place routers in a full mesh topology. This could be problematic for the following reasons.
Spoke routers will need extensive configuration
Additional virtual circuits are required for each network entity to reach the other in a single hop. This would result in significant costs.
It can take too long to set up and troubleshoot a system, which could lead to overload for already busy IT staff.
Next Hop Resolution Protocol is much more efficient than using it, because it allows components of the network to “see” each other without requiring each node through lengthy, time-consuming, and expensive configurations.
How does NHRP Commands work
Let’s suppose you have a simple network that has two clients, A2 and A3, and a single server, S1. Traditional setups would be the best.
