A potential point of confusion in L2TP/IPsec is the use of the terms tunnel and secure channel. The term tunnel-mode refers to a channel which allows untouched packets of one network to be transported over another network. In the case of L2TP/PPP, it allows L2TP/PPP packets to be transported over IP. A secure channel refers to a connection within which the confidentiality of all data is guaranteed. In L2TP/IPsec, first IPsec provides a secure channel, then L2TP provides a tunnel. IPsec also specifies a tunnel protocol: this is not used when a L2TP tunnel is used.