pppoe and pppoe relay issue

yaxinzhu

PPPoE requires certain signals and information to establish, accept, control and terminate the session. The basic signalling is shown below.
A PADI (PPPoE Active Discovery Initiation) broadcast signal is sent by the host to the remote devices.
A PADO (PPPoE Active Discovery Offer) signal is sent by the remote device back to the host.
A PADR (PPPoE Active Discovery Request) unicast signal is sent by the host to the remote device.
A PADS (PPPoE Active Discovery Session-Confirmation) is sent by the remote device back to the host.
A PADT (PPPoE Active Discovery Terminate) signal is sent to terminate a PPPoE session. It is the proper way to terminate a session but is not the actual cause for the termination. The cause may be a simple timeout, a manual request by either end, or an out of spec line condition.

Relay PPPOE session, PPPOE connection will failure if The frame out "Session relay ID".

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