Figure 12-1 Encryption And Decryption - Nortel Contivity 221 User Manual

12-2 Introduction to IPSec

Figure 12-1 Encryption and Decryption

Data Confidentiality
The IPSec sender can encrypt packets before transmitting them across a network.
Data Integrity
The IPSec receiver can validate packets sent by the IPSec sender to ensure that the data has
not been altered during transmission.
Data Origin Authentication
The IPSec receiver can verify the source of IPSec packets. This service depends on the data
integrity service.
12.1.4 VPN Applications
The Contivity 221 supports the following VPN applications.
Linking Two or More Private Networks Together
Connect branch offices and business partners over the Internet with significant cost savings
and improved performance when compared to leased lines between sites.
Accessing Network Resources When NAT Is Enabled
When NAT is enabled, remote users are not able to access hosts on the LAN unless the
host is designated a public LAN server for that specific protocol. Since the VPN tunnel
terminates inside the LAN, remote users will be able to access all computers that use
private IP addresses on the LAN.
Unsupported IP Applications
A VPN tunnel may be created to add support for unsupported emerging IP applications.
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