encapsulation-mode

Use encapsulation-mode to set the encapsulation mode that the security protocol uses to encapsulate IP packets.

Use undo encapsulation-mode to restore the default.

Syntax

encapsulation-mode { transport | tunnel }

undo encapsulation-mode

Default

IP packets are encapsulated in tunnel mode.

Views

IPsec transform set view

Predefined user roles

network-admin

mdc-admin

Parameters

transport: Uses the transport mode for IP packet encapsulation.

tunnel: Uses the tunnel mode for IP packet encapsulation.

Usage guidelines

IPsec supports the following encapsulation modes:

• Transport mode—The security protocols protect the upper layer data of an IP packet. Only the transport layer data is used to calculate the security protocol headers. The calculated security protocol headers and the encrypted data (only for ESP encapsulation) are placed after the original IP header. You can use the transport mode when end-to-end security protection is required (the secured transmission start and end points are the actual start and end points of the data). The transport mode is typically used for protecting host-to-host communications.

• Tunnel mode—The security protocols protect the entire IP packet. The entire IP packet is used to calculate the security protocol headers. The calculated security protocol headers and the encrypted data (only for ESP encapsulation) are encapsulated in a new IP packet. In this mode, the encapsulated packet has two IP headers. The inner IP header is the original IP header. The outer IP header is added by the network device that provides the IPsec service. You must use the tunnel mode when the secured transmission start and end points are not the actual start and end points of the data packets (for example, when two gateways provide IPsec but the data start and end points are two hosts behind the gateways). The tunnel mode is typically used for protecting gateway-to-gateway communications.

The IPsec transform sets at both ends of the IPsec tunnel must have the same encapsulation mode.

Examples

# Configure IPsec transform set tran1 to use the transport mode for IP packet encapsulation.

<Sysname> system-view
[Sysname] ipsec transform-set tran1
[Sysname-ipsec-transform-set-tran1] encapsulation-mode transport

Related commands

ipsec transform-set