?– IPsec is the framework that combines security protocols and provides VPNs with data
con?¬?dentiality, integrity, and authentication.
?– AH and ESP are the two main IPsec framework protocols.
ESP
ESP
+AH
Choices:
IPsec
Framework
DH
Authentication
Encryption
IPsec Protocol AH
DES
3
DES AES
MD5 SHA
DH1 DH2 DH5
Establishing a Point-to-Point WAN Connection with PPP 315
Establishing a Point-to-Point WAN Connection
with PPP
Wide-area networking services are typically leased from a service provider. Some WAN
services operate as Layer 2 connections between your remote locations and are typically
provided by a telephone company (telco) provider over its WAN switches.
PPP emerged as an encapsulation protocol for transporting IP traf?¬?c over point-to-point
(leased line) serial connections. This section describes the operation, con?¬?guration, and
veri?¬?cation of PPP.
Understanding WAN Encapsulations
On each WAN connection, data is encapsulated into frames before it crosses the WAN link. To
ensure that the correct protocol is used, you must con?¬?gure the appropriate Layer 2 encapsulation
type. The choice of Layer 2 protocol depends on the WAN technology and the communicating
equipment.
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