When WAN access is provided with ppp authentication, we have to clarify with provider the following 2 scenarios:
1. if AR will authenticate remote device(telecom provider)
2. if AR will be authenticated by the remote device(telecom provider).
For this 2 scenarios AR200 router commands differ:
1. ppp authentication-mode chap or ppp authentication-mode pap
in this case AR router will authenticate the remote device and remote device should provide the username and password
2. ppp chap user xxxxx
ppp chap password simple yyyyyy
in this case remote device will authenticate and AR need to provide username and password.
Second scenario is mostly used, from scalability reasons, remote device (telecom provider) will athenticate its peers.
