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ADSL Hardware ........... .......................................................................................................................... 13-5
NIM Card .......................................................................................................................................... 13-5
ADSL on the Motherboard............................................................. ...................................................13-6
DSP Firmware .................................................................................................................................. 13-6
ADSL Data Framing ........................................ ....................................................................................... 13-6
ATM Support ................................................ .......................................................................................... 13-6
Virtual Circuits ............................................................................................................................ ...... 13-6
OAM Cells ............................................................................................................... .........................13-7
Performance Monitoring ................................................................................................................... 13-7
Class of Service...................................................................................... ..........................................13-7
DSLAM Compatibility ............ ................................................................................................................. 13-7
Access Concentrator Restrictions .......................... ................................................................................ 13-7
Inverse ARP ....................................... .................................................................................................... 13-8
QoS .............................................................................................................. ..........................................13-8
SNMP ............................................................................................................... ......................................13-8
Configuration Examples ............................................................................................................................... 13-8
PPPoE........................................................................................................................................... ... 13-8
PPPoA........................................................................................................................................... ... 13-9
IPoA........................................................... ..................................................................................... 13-10
Chapter 14: Configuring the Virtual Private Network
VPN Overview .... .......................................................................................................................................... 14-1
Internet Security Issues ................................................................................................. .........................14-1
How a Virtual Private Network Works .................................................................................................... 14-2
Ensuring VPN Security with IPSec/IKE/GRE ............................................................................................... 14-2
GRE over IPSec ........................................................................ .............................................................14-4
Defining VPN Encryption .................................................................................................. ......................14-5
Describing Public-Key Infrastructure (PKI) ............... .................................................................................... 14-5
Digital Signatures ............................................... .................................................................................... 14-5
Certificates ............................................................................................................. ................................14-6
Machine Certificates for the XSR ........................................................................................................... 14-6
CA Hierarchies ............................................. .......................................................................................... 14-7
Certificate Chains ......................................................................... ..........................................................14-7
RA Mode .................. .............................................................................................................................. 14-8
Pending Mode ................................................. ....................................................................................... 14-9
Enroll Password .............. ....................................................................................................................... 14-9
CRL Retrieval ......................................................................... ................................................................14-9
Renewing and Revoking Certificates .............. ....................................................................................... 14-9
DF Bit Functionality ................................................................................................................................... ... 14-9
VPN Applications ................................................................... ..................................................................... 14-10
Site-to-Site Networks ........................................................................................................................... 14-11
Site-to-Central-Site Networks .............................................................................................. .................14-11
NAT Traversal ............................................................................................................................ .... 14-11
Client Mode ................................................................................................................... .................14-12
Network Extension Mode (NEM) ....................................................................................................14-13
Remote Access Networks ............................... ..................................................................................... 14-13
Using OSPF Over a VPN Network ............................................................... ........................................14-14
OSPF Commands .......................................................................................................................... 14-14
Configuring OSPF Over Site-to-Central Site in Client Mode .......................................................... 14-14
Configuring OSPF over Site-to-Central Site in Network Extension Mode ...................................... 14-16
Server........................... .................................................................................... .............................. 14-17
Client ................................................................................................................ ..............................14-17
Configuring OSPF with Fail Over (Redundancy)........................................... .................................14-17