PPPoE "Forwarded" state, how it is made ?

[Louey]

Hi

As a member of a service provider company, I noticed that in our LNS "normally the terminaison points for PPP and PPPoE sessions" I have some session in "Forwarded" states, this means that client authentication is done in another device.

Which I could not understand, is that how the PPPoE session arriving in a layer 2 ethernet link with a vlan to our LNS can be forwarded to another device through the backbone ? Is the PPP session forwarded on an l2tp tunnel due to radius response to LNS ? Or the forwarded frame is still a PPPoE one and how this is made ?

THANKS

[MHM Cisco World · Accepted solution]

PPPoEClient-SW-LAC-LNS 
between PPPoEClient-SW-LAC there is PPPoE session 
between LAC-LNS there is PPP session over L2TP (VPDN)

the user enter Username/Password the LAC check this Username/Password with domain config under VPDN-Group and LAC select the LNS to connect, the connect is through  VPND (L2TP).

then finally the PPP is pass from Client to LNS , the Client appear as direction connect to LNS and can access any resource.

you see I ping from PPPoEClient to LNS the traffic is PPPoE then PPP over L2TP