question about ppp encapsulation

jsond

i understand if the encapsuation on both sides of 2 routers serial links do not match then if you ran a 'show int s0' command the output would 1st show that "serial 0 is up, line protocol is down". However if both sides were set to ppp encapsulation but only one side was set to 'ppp authentication chap" would line protocol be up or down? not to mention lcp. its responsibility is to handle the authentication, in this scenario would it be set to LCP=open or closed.

My thinking is line protocol would still show up (since both sides are set to the same encapsulation) but LCP would not be = to OPEN since the authentication is not the same.

I only have labs from cd's to reference and not a true router to router setup so I apologize for asking but I am a bit confused on this one.

Thanks in advance for any help.

johnnynodough

A PPP link wont be established if CHAP or PAP is configured on one end and not the other (or misconfigured) , PPP is the line protocol, and LCP negotiation is necassary to establish a PPP link, same end result as if you have PPP on one end and HDLC on the other.....I think you see where I am going with this.

dtwiss0207

In regards to LCP and NCP. What portion of PPP negotiates the L3 protocols to be carried over the link? It is my understanding that LCP established the link and offers authentication and then NCP negotiates the protocols.