Explanation:
IKE uses “Tunneling mode” encryption, which works by encapsulating the entire packet, and then adding its own encryption protocol header to the encrypted packet. A drawback of using tunneling mode encryption is that the packet size has been increased. This increase in the packet size degrades network performance, however, the security of the packet is increased. See Page 7.15 of CCSE NG Official Courseware. (VPN1-FW1 Management II NG FP-1).

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