A good helper for managing the Auxiliary port and Console port Cisco Router

Network administrators often need to connect to a vro to perform configuration verification, and statistical data review on the Cisco router. There are many methods to connect to a Cisco router, such as configuring a port, a secondary port, or using Telnet. However, I like to connect to the vro through the Console port for related management and configuration.

The secondary port and Console port are the same, and their functions are basically the same. To this end, the network administrator can use it like using the Console port. However, the Console port cannot be implemented. To manage the Cisco router through the Console port, you must be in front of the router. If we use the Auxiliary port to manage the router, the network administrator can control it even if it is thousands of miles away. When a vro encounters a problem or the network administrator needs to view some information, remote dialing can be used to connect to the vro that is "disconnected from the network" through the Auxiliary port. It is precisely because of this outstanding function that it is particularly welcomed by our network administrator.

If you want to use the Auxiliary port, there are also some tips. I will discuss how to use the Auxiliary port of the Cisco router better.

Tip 1: Use the Auxiliary port as the backup Console Port

As we all know, the function of the Auxiliary port is consistent with that of the Console port. However, it cannot be used as the second Console port by default. This is mainly because the Console port and the Auxiliary port have different shapes, so it cannot be used in general. However, sometimes, if the Console port fails or for other reasons, we often need to use the Auxiliary port as the Console port.

In fact, this is also a very easy task. I don't know how it works. There is a special cable in my toolbox. Using this cable, you can convert the interface type of the secondary port to the interface type of the configured port. These cables are basically available on the market. If the network administrator finds this need, they can also configure one to prevent the problem.

In practice, we often connect the serial port of our laptop to the secondary port of the router through a dedicated configuration connection line for router configuration and maintenance.

Tip 2: Use the Auxiliary port as an asynchronous serial interface

On Some routers, do you have to configure asynchronous serial interfaces. In this case, the network administrator needs to configure the Auxiliary port as an asynchronous serial port. To achieve this, the network administrator can use the line aux command to configure the Auxiliary port as a secondary line.

However, this is different from the preceding Console port. Although asynchronous serial interfaces can be implemented through Auxiliary ports, they are not professional after all, so the performance of asynchronous serial interfaces cannot be achieved.

For example, asynchronous serial interfaces support Direct Memory Access. That is to say, the router buffer directly stores data in groups and reads the system memory, without the intervention of the router CPU. Obviously, this feature reduces the CPU overhead of the router and improves the performance of the router.

If a router has an asynchronous serial interface, a PPP frame on its hardware chip can be used to eliminate the overhead of the router's central processor. This feature ensures that the router maintains a high-speed connection over all asynchronous ports at the same time. This is useful in actual management. Especially when several network management experts jointly discuss network faults, the value will be reflected.

However, although secondary ports are used as Asynchronous ports, they cannot achieve the same performance as professional asynchronous serial interfaces. However, it can basically meet common management needs.

Tip 3: Set an independent password for the Auxiliary port to improve the security of the router

As described above, we know that the secondary port can play the same role as the Console port. Therefore, when the password of the secondary port is leaked and is remotely connected to the vro, the attack on the enterprise network will be fatal. Therefore, to improve security, the Cisco router sets password management for the Auxiliary port.

Therefore, it is recommended that the network administrator do not use the same password as other passwords in password settings. Otherwise, the security of the router is reduced.

In short, the Auxiliary port plays an important role in vro management. Generally, the Console port is used only when the vro is configured. In the process of subsequent network maintenance and router troubleshooting, secondary ports are often used. Therefore, the Auxiliary port is a good helper in vro management.

1. Cisco-console and AUX port cable guide
2. Starting from vro for network protection -- talking about CISCO Router Security Configuration