According to technical references, the Next Hop field in the EIGRP IP Internal and External Routes TLVs identifies the next-hop router to send packets destined for a destination network. I have performed some POC regarding the Next Hop field but it...

From the following document: http://www.cisco.com/en/US/tech/tk713/tk507/technologies_tech_note09186a0080093c6f.shtml, it states that "ppp authentication pap callin" will be issued on the calling router. But why "callin" and not "callout"? Thanks! :)