Serial0/1/1, changed state to down When use the encapsulation PPP

[blakpat]

Good afternoon,

I am setting up PPP encapsultion and ppp chap authentication on two routers and two serial interfaces.

When I configure PPP, on the serial interface the status changed to inactive and this does not allow me to make a communication from router to router.

This is an example of error

My PKT In case it's necessary -- https://drive.google.com/file/d/1H-tO_Gb35TZYY3ac1idcn1RM9iF6DpAk/view?usp=sharing

THIS IS EXAMPLE

[luis_cordova · Accepted solution]

Hi @blakpat 

By default, the encapsulation of serial interfaces is HDLC.
This encapsulation must be equal at both ends of the link for the interface to be UP.

When you change the encapsulation at one end, it is normal for the interface to go DOWN, until the other end has the same encapsulation.

You should also keep in mind that the name of a router and the user allowed on the neighboring router must match for connectivity to be successful.
Another detail is that the password configured on both routers must be the same.

I leave you this link in case you want to go deeper:

https://www.cisco.com/c/en/us/support/docs/wan/point-to-point-protocol-ppp/25647-understanding-ppp-chap.html

Regards

[blakpat]

Thank you very much @luis_cordova  for the information, I will review it!