PPP authentication fail

Publication Date:  2014-09-15 Views:  739 Downloads:  0
Issue Description
Configuration 3G interface:
interface Cellular0/0/0
link-protocol ppp
ppp authentication-mode chap             
ppp chap user x@net.umts
ppp chap password simple pass
ip address ppp-negotiate
dialer enable-circular
dialer-group 1
dialer number *99#
Alarm Information
PPP authetication fails, no ip address is obtained from ISP.
Handling Process
using ppp authentication-mode chap command under 3g interface, the AR Router will be the authenticator and will authenticate the ISP device and the remote device should provide the username and password.
We must undo ppp authentication-mode chap  and ISP device will be the authenticator, will authenticate the AR. Ar will be authenticated device and must provide username and password.
Root Cause
We clarified with the ISP regarding the roles of the authenticator device and authenticated device.
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.