Cisco Cisco Packet Data Interworking Function (PDIF) Guía Para Resolver Problemas
IP Security
▀ Implementing IPSec for L2TP Applications
▄ Cisco ASR 5000 Series Enhanced Feature Configuration Guide
OL-22982-01
Step
Description
4.
From the crypto map, the system determines the following:
The map type, in this case dynamic
Whether perfect forward secrecy (PFS) should be enabled for the IPSec SA and if so, what group should be used
IPSec SA lifetime parameters
The name of one or more configured transform set defining the IPSec SA
5.
To initiate the IKE SA negotiation, the system performs a Diffie-Hellman exchange of the ISAKMP secret specified by the
attribute with the specified peer LNS/security gateway.
attribute with the specified peer LNS/security gateway.
6.
The system and the LNS/security gateway negotiate an ISAKMP policy (IKE SA) to use to protect further
communications.
communications.
7.
Once the IKE SA has been negotiated, the system negotiates an IPSec SA with the LNS/security gateway.
8.
Once the IPSec SA has been negotiated, the system protects the L2TP encapsulated data according to the rules specified in
the transform set and sends it over the IPSec tunnel.
the transform set and sends it over the IPSec tunnel.
Configuring Support for L2TP PDSN Compulsory Tunneling with IPSec
This section provides a list of the steps required to configure IPSec functionality on the system in support of PDSN
compulsory L2TP tunneling. Each step listed refers to a different section containing the specific instructions for
completing the required procedure.
compulsory L2TP tunneling. Each step listed refers to a different section containing the specific instructions for
completing the required procedure.
Important:
These instructions assume that the system was previously configured to support PDSN compulsory
tunneling subscriber data sessions. In addition, all parameters configured using this procedure must be configured in the
same destination context on the system as the LAC service.
same destination context on the system as the LAC service.
Step 1
Configure one or more transform sets according to the instructions located in the
of this chapter.
Step 2
section of this chapter.
Step 3
Configure an ipsec-isakmp crypto map according to the instructions located in the
section of this chapter.
Step 4
Step 5
Save your configuration as described in Verifying and Saving Your Configuration.