ccna book cost

ccna book cost.8.3.2.5 Transport and Tunneling ModesESP and AH can be applied to IP packets in two modes: transport mode and tunnel mode.Transport ModeIn transport mode, security is provided only for the transport layer and above of the OSI model. Transport mode protects the packet load, but the original IP address remains in plaintext. The original IP address is used to transmit packets over the Internet.ESP transport mode is used between hosts. Transport mode works with GRE because the GRE hides the address of the end device by adding its own 1P hiding.Tunnel ModeTunnel mode provides security for the entire raw IP packet. The original IP packet is encrypted and then encapsulated into another IP packet, which is called IP.in-IP encryption. The IP address of the outer IP packet is used to transmit the packet over the Internet.ESP tunnel mode is used between a host and a secure gateway or between two secure gateways. For gateway-to-gateway applications, it is easier to have the secure gateway perform JP-in-IP encryption and encapsulation as opposed to loading IPSec for all computers at remote locations and corporate offices.ESP tunneling mode is used for IPSec remote access applications. The home office may not have a router to perform IPSec encapsulation and encryption. In this case, an IPSec client running by the PC± performs IPSec IP-in-IP encapsulation and encryption. In the corporate office, the router decapsulates and decrypts the packets.The VPN process involves the selection and application of many parameters. In practice, how does IPSec negotiate these security parameters?