Monday, May 11, 2009

Finished PPP Chapter 12

I finished studying the ICND2 Point-to-Point Protocol (PPP) chapter which is pretty straight forward. Honestly if you went through the ICND1 PPP chapters then you can skim through most of this as it's basically the same info. There really isn't to much to PPP at least at the CCNA level besides setting up Authentication. The two ways to authenticate is by using PAP or CHAP with CHAP being the preferred method. Reason being is that it encrypts the password and actually never sends the password across the serial WAN link. Troubleshooting PPP might be tricky becuase of the way it sends keepalives compared to other protocols such as STP, OSPF, etc. Reason being is that it sends what's called a host route to it's neighbor router. This host route is the enitre /32 mask so there's no way to know if the link is in the wrong subnet through PPP. Therefore two interfaces might be in UP/UP statuses but in different subnets. So while they can ping each other they can't ping further than that because routing tables see these two interfaces in different subnets! Hope that makes since some how lol

No comments:

Post a Comment