The tunnel avp-hidden command configures transmitting of Attribute Value Pair (AVP) data in the hidden mode.
The undo tunnel avp-hidden command restores the default transmission way of AVP data.
By default, the tunnel transmits AVP data in plain text.
This command is configured on the NAS and applies only to NAS-Initiated scenarios.
AVP data carries some parameters of the L2TP protocol. For the purpose of security, you can configure AVP data to be transmitted in the hidden mode by using this command.
The hidden AVP function takes effect only when authentication is configured on both ends of a tunnel.