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
5.
To initiate the IKE SA negotiation, the system performs a Diffie-Hellman exchange of the ISAKMP secret specified in the
profile attribute with the specified peer LNS/security gateway.
profile attribute with the specified peer LNS/security gateway.
6.
The system and the LNS/security gateway negotiate an ISAKMP (IKE) policy to use to protect further communications.
7.
Once the IKE SA has been negotiated, the system negotiates an IPSec SA with the LNS/security gateway using the
transform method specified in the transform sets.
transform method specified in the transform sets.
8.
Once the IPSec SA has been negotiated, the system protects the L2TP encapsulated data according to the IPSec SAs
established during step 9 and sends it over the IPSec tunnel.
established during step 9 and sends it over the IPSec tunnel.
Configuring GGSN Support for L2TP Tunneling with IPSec
This section provides a list of the steps required to configure the GGSN to encrypt L2TP tunnels using IPSEC. Each
step listed refers to a different section containing the specific instructions for completing the required procedure.
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 subscriber PDP
contexts and L2TP tunneling either as a GGSN. In addition, all parameters configured using this procedure must be
configured in the same destination context on the system as the LAC service.
configured in the 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
Configure APN support for encrypting L2TP tunnels using IPSec according to the instructions located in the
Step 5
Save your configuration as described in Verifying and Saving Your Configuration.