Understand the next hop address in the network topology in seconds

Hello, this is the Network Technology Alliance site.

Today I want to talk to you about an interesting, but also very basic technique: Next hop.

The "down" here is not "scare".

Before we talk about the next hop, it is necessary to talk about the common and basic network equipment in the network: router.

What is a router?

Friends who are reading this article, 99% of people know what a router is, so I will express it in one sentence here: A router is at Layer 3 or the OSI modelNetwork devices running at the >Network layer.

The role of the router

Responsible for receiving, analyzing, and forwarding packets between connected computer networks. When a packet arrives, the router checks the destination address, looking up its routetable to determine the best route, and then transmit the packet along that route.

The type of router

Common routers are of the following types:

• Wireless Router
• Wired Router (Broadband Router)
• Edge Router
• Core router
• Virtual Router

Wireless routers are the most commonly used at home. This is no stranger to everyone. Enterprise-level routers are generally used in the above five types, depending on the size of the network.

Network Topology

After talking about routers, let's take a look at the network topology:

As shown in the figure above, the above figure is a simple network topology. A network topology is a network structure formed by connecting various network devices through certain media.

The next hop address we often say is displayed in the network topology.

So what is the next hop address?

Next hop address

Next hop is a routing term that refers to the next closest router through which a packet can pass.

More specifically, a next hop is an IP address entry in a router's routing table that specifies the next closest/best router in its routing path.

Let's explain next-hop addresses through a simple topology.

There are four devices in the picture above, two PCs, two routers, and two communication lines:

1. PC1 actively initiates communication with PC2
2. PC2 actively initiates communication with PC1

We know that the next hop refers to the next closest router. The next one here is relative, that is, a reference point. For example, when PC1 actively initiates communication with PC2,The next hop address of Router1 is Router2; when PC2 initiates communication with PC1, the next hop address of Router2 is Router1.

Seeing here, can we summarize again: the next hop address is the optimal distance in the network link from the current device to the target device.>The address of the next device.

This is easy to understand the above picture: when PC1 actively initiates communication with PC2, the data packet arrives at Router1, and Router1 in this communication link target device is PC2, then the data packet is inInternally, Router1 starts to calculate routing, and obtains the current optimal distance to the next device is Router2, so for the current device Router1, the next hop address is the address of the direct interface between Router2 and Router1.

Note: The hop count is incremented by one each time a packet passes through the router.For example, if the destination is 10 hops from the source, the packet must go through 10 different routers to reach it.

My friends, do you understand?