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Cisco IOS XR Software Release 5.2 Configuration Guide

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Cisco ASR 9000 Series Aggregation Services Router Broadband
Network Gateway Configuration Guide, Release 5.2.x
First Published: 2014-07-03
Last Modified: 2014-10-24
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CONTENTS
Preface
Preface xi
Changes to This Document xi
Obtaining Documentation and Submitting a Service Request xi
CHAPTER 1
New and Changed BNG Features 1
New and Changed BNG Feature Information 1
CHAPTER 2
Broadband Network Gateway Overview 5
Understanding BNG 5
BNG Architecture 6
BNG Role in ISP Network Models 8
BNG Packaging 9
Installing and Activating the BNG Pie on Cisco ASR 9000 Series Router 9
BNG Configuration Process 11
Hardware Requirements for BNG 11
BNG Interoperability 12
BNG Smart Licensing 13
CHAPTER 3
Configuring Authentication, Authorization, and Accounting Functions 15
AAA Overview 16
Using RADIUS Server Group 17
Configuring RADIUS Server Group 17
Specifying Method List 19
Configuring Method Lists for AAA 20
Defining AAA Attributes 21
Creating Attributes of Specific Format 22
Configuring RADIUS Attribute List 27
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Configuring RADIUS Attribute Format 28
Configuring RADIUS Attribute Nas-port-type 29
Configuring AAA Attribute Format Function 30
Making RADIUS Server Settings 31
Configuring RADIUS Server Settings 32
Configuring Automated Testing 36
Setting IP DSCP for RADIUS Server 36
Balancing Transaction Load on the RADIUS Server 37
Configuring Load Balancing for Global RADIUS Server Group 38
Configuring Load Balancing for a Named RADIUS Server Group 39
Throttling of RADIUS Records 39
Configuring RADIUS Throttling Globally 40
Configuring RADIUS Throttling on a Server Group 41
RADIUS Change of Authorization (CoA) Overview 43
Multi-Action Change of Authorization 45
Generating Accounting Records 46
High Availability for MA-CoA 46
An Example with Verification Commands 47
Restrictions in Multi-Action Change of Authorization 50
User Authentication and Authorization in the Local Network 50
Policy Configurations for IPoE Sessions 51
Policy Configurations for PTA Sessions 54
Service Accounting 55
Configuring Service Accounting 56
Statistics Infrastructure 58
Configuring Statistics IDs (statsD) 59
Understanding Per-VRF AAA Function 59
RADIUS Double-Dip Feature 60
Additional References 60
CHAPTER 4
Activating Control Policy 63
Control Policy Overview 63
Creating Class-Map 65
Configuring a Class-Map 65
Creating Policy-Map 66
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Control Policy Events 66
Configuring a Policy-Map 68
Activating Policy-Map 70
Enabling a Service-Policy on a Subscriber Interface 70
Defining Dynamic Templates 70
Additional References 72
CHAPTER 5
Establishing Subscriber Sessions 73
Subscriber Session Overview 74
Establishing IPoE Session 76
Enabling IPv4 or IPv6 on an Access Interface 78
Creating Dynamic Template for IPv4 or IPv6 Subscriber Session 79
Creating a Policy-Map to Run During IPoE Session 81
Enabling IPoE Subscribers on an Access Interface 82
Routed Subscriber Sessions 85
DHCP-initiated Routed Subscriber Sessions 87
Call Flow of DHCPv4-initiated Routed Subscriber Sessions 88
Packet-triggered Routed Subscriber Sessions 89
Deployment Model for IPv6 Routed Network 90
Call Flow of IPv6 Routed Subscriber Session 91
Restrictions for Routed Subscriber Sessions 91
Configuring Routed Subscriber Sessions 92
Establishing PPPoE Session 94
Provisioning PPP PTA Session 95
Creating PPPoE Profiles 95
Creating a PPP Dynamic-Template 96
Creating a Policy-Map to Run During PPPoE Session 97
Modifying VRF for PPPoE Sessions 99
Applying the PPPoE Configurations to an Access Interface 100
Provisioning PPP LAC Session 101
Configuring the VPDN Template 102
Configuring Maximum Simultaneous VPDN Sessions 104
Activating VPDN Logging 105
Configuring Options to Apply on Calling Station ID 106
Configuring L2TP Session-ID Commands 107
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Configuring L2TP Class Options 108
Configuring Softshut for VPDN 110
L2TP Reassembly on LAC 111
Enabling L2TP Reassembly on LAC 112
L2TP Access Concentrator Stateful Switchover 113
Enabling LAC SSO 113
Enabling RPFO on Process-failures 114
PPPoE Smart Server Selection 115
Configuring PADO Delay 116
PPPoE Session Limit, Throttle and In-flight-window 118
PPPoE Session Limit 118
Configuring PPPoE Session Limit 118
PPPoE Session Throttle 119
Configuring PPPoE Session Throttle 120
PPPoE In-flight-window 121
Making DHCP Settings 121
Enabling DHCP Proxy 122
Configuring DHCP IPv4 Profile Proxy Class 123
Configuring a Circuit-ID for an Interface 124
Configuring a Remote-ID 125
Configuring the Client Lease Time 126
Attaching a Proxy Profile to an Interface 127
DHCPv4 Server 128
Enabling DHCP Server 128
Configuring DHCPv4 Server Profile 129
Specifying DHCP Lease Limit 132
Specifying the Lease Limit for a Circuit-ID 132
Specifying the Lease Limit for a Remote-ID 133
Specifying the Lease Limit for an Interface 134
Understanding DHCP Option-82 135
Option 82 Relay Information Encapsulation 136
Configuring DHCPv4 Class of Service (CoS) 136
DHCP RADIUS Proxy 136
Subscriber Session-Restart 137
DHCP Session MAC Throttle 137
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DHCPv6 Overview 138
DHCPv6 Server and DHCPv6 Proxy 139
Enabling DHCPv6 for Different Configuration Modes 139
Setting Up DHCPv6 Parameters 142
DHCPv6 Features 144
High Availability Support for DHCPv6 145
DHCPv6 Prefix Delegation 145
IPv6 IPoE Subscriber Support 145
Configuring IPv6 IPoE Subscriber Interface 146
IPv6 PPPoE Subscriber Support 152
Configuring IPv6 PPPoE Subscriber Interfaces 152
Ambiguous VLAN Support 158
Configuring Ambiguous VLANs 158
DHCPv6 Address or Prefix Pool 160
Configuring IPv6 Address or Prefix Pool Name 160
DHCPv6 Dual-Stack Lite Support 162
Configuring AFTR Fully Qualified Domain Name for DS-Lite 163
VRF Awareness in DHCPv6 164
Defining VRF in a Dynamic Template 164
Rapid commit 165
Packet Handling on Subscriber Interfaces 165
IPv6 Neighbor Discovery 167
Line Card Subscribers 167
External Interaction for LC Subscribers 168
Benefits and Restrictions of Line Card Subscribers 168
High Availability for Line Card Subscribers 169
Static Sessions 170
Restrictions for static sessions 171
Subscriber Session Limit 171
eBGP over PPPoE 172
BNG over Pseudowire Headend 173
QoS on BNG Pseudowire Headend 173
Features Supported for BNG over Pseudowire Headend 174
Unsupported Features and Restrictions for BNG over Pseudowire Headend 175
Additional References 175
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CHAPTER 6
Deploying the Quality of Service (QoS) 177
Quality of Service Overview 178
Configuring Service-policy and Applying Subscriber Settings Through RADIUS 179
Configuring Service-policy and Applying Subscriber Settings Through Dynamic
Template 180
Parameterized QoS 183
Parameterized QoS Syntax 184
Configuring Parameterized QoS Policy Through RADIUS 189
Modifying Service Policy through CoA 191
RADIUS Based Policing - QoS Shaper Parameterization 193
Sample Configuration and Use Cases for QoS Shaper Parameterization 194
Verification of QoS Shaper Parameterization Configurations 194
Supported Scenarios of QoS Shaper Parameterization 197
Restrictions of QoS Shaper Parameterization 197
QoS Accounting 198
Configuring QoS Accounting 199
Support for Shared Policy Instance 200
Configuring a Policy with SPI in the Input or Output Direction Using Dynamic
Template 201
Configuring a Policy with SPI in the Input or Output Direction Using RADIUS 204
Merging QoS Policy-maps 206
Enabling Policy-maps Merge 206
QoS Features Supported on BNG 210
VLAN Policy on Access Interface 214
Configuring Policy on S-VLAN 214
Configuring VLAN Policy on an Access Interface 215
Additional References 217
CHAPTER 7
Configuring Subscriber Features 219
CHAPTER 8
BNG Geo Redundancy 279
Geo Redundancy Overview 279
Subscriber Redundancy Group (SRG) 281
Session Distribution Across SRG 282
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Benefits of BNG Geo Redundancy 284
Supported Features in BNG Geo Redundancy 284
BNG Geo Redundancy Configuration Guidelines 285
Setting up BNG Subscriber Redundancy Group 287
Deployment Models for BNG Geo Redundancy 288
APPENDIX A
XML Support for BNG Features 289
AAA XML Support 289
DHCP XML Support 292
Control Policy XML Support 295
DAPS XML Support 298
PPPoE XML Support 300
Subscriber Database XML Support 302
APPENDIX B
RADIUS Attributes 307
RADIUS IETF Attributes 307
IETF Tagged Attributes on LAC 309
RADIUS Vendor-Specific Attributes 310
Vendor-Specific Attributes for Account Operations 315
RADIUS ADSL Attributes 315
RADIUS ASCEND Attributes 316
RADIUS Microsoft Attributes 317
RADIUS Disconnect-Cause Attributes 317
APPENDIX C
Action Handlers 323
APPENDIX D
BNG Use Cases and Sample Configurations 325
BNG over Pseudowire Headend 325
Sample Topology for BNG over Pseudowire Headend 325
Deployment Models for Subscribers on Pseudowire Headend 326
Residential Subscribers on Pseudowire Headend 326
Residential and Business Subscribers on Pseudowire Headend 328
Configuration and Verification of BNG over Pseudowire Headend 330
Sample Configurations for BNG over Pseudowire Headend 332
Dual-Stack Subscriber Sessions 334
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IP Address Assignment for Clients 334
Sample IPv6 Addressing and Configurations 335
IPv6 Address Mapping 335
CPE Configurations 335
DHCPv6 Server Configuration 336
Operation and Call Flow of Dual-Stack Sessions 336
Generic Call Flow of Dual-Stack Session 337
Detailed Call Flows - PPPoE Dual-Stack 339
Scenario 1: SLAAC-Based Address Assignment 339
Scenario 2: DHCPv6-Based Address Assignment 340
Detailed Call Flows - IPoE Dual-Stack 341
Scenario 1 - IPv4 Address-Family Starts First 341
Scenario 2 - IPv6 Address-Family Starts First 342
Sample Topology for Dual-Stack 343
Configuration Examples for Dual-Stack 343
Verification Steps for Dual-Stack 345
eBGP over PPPoE 346
Sample Topology for eBGP over PPPoE 346
Configuration and Verification of eBGP over PPPoE 347
Sample Configurations for eBGP over PPPoE 348
Routed Subscriber Sessions 354
Routed Subscriber Deployment Topology and Use Cases 354
Sample Configurations for Routed Subscriber Session 355
Verification of Routed Subscriber Session Configurations 357
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Contents
Preface
From Release 6.1.2 onwards, Cisco introduces support for the 64-bit Linux-based IOS XR operating system.
Extensive feature parity is maintained between the 32-bit and 64-bit environments. Unless explicitly marked
otherwise, the contents of this document are applicable for both the environments. For more details on Cisco
IOS XR 64 bit, refer to the Release Notes for Cisco ASR 9000 Series Routers, Release 6.1.2 document.
This Preface contains these sections:
•Changes to This Document, page xi
•Obtaining Documentation and Submitting a Service Request, page xi
Changes to This Document
This table lists the technical changes made to this document since it was first released.
Table 1: Changes to This Document
SummaryDate
Republished with documentation updates for Cisco
IOS XR Release 5.2.2 features.
October 2014
Initial release of this document.July 2014
Obtaining Documentation and Submitting a Service Request
For information on obtaining documentation, using the Cisco Bug Search Tool (BST), submitting a service
request, and gathering additional information, see What's New in Cisco Product Documentation.
To receive new and revised Cisco technical content directly to your desktop, you can subscribe to the What's
New in Cisco Product Documentation RSS feed. RSS feeds are a free service.
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Preface
Obtaining Documentation and Submitting a Service Request
CHAPTER 1
New and Changed BNG Features
This table summarizes the new and changed feature information for the Cisco ASR 9000 Series Aggregation
Services Router Broadband Network Gateway Configuration Guide, and tells you where they are documented.
•New and Changed BNG Feature Information, page 1
New and Changed BNG Feature Information
Where DocumentedChanged in ReleaseDescriptionFeature
Establishing Subscriber
Sessions chapter:
•Geo Redundancy
Overview, on page 279
Refer Subscriber Commands
chapter in Cisco ASR 9000
Series Aggregation Services
Router Broadband Network
Gateway Command Reference,
for information on the
commands used for BNG Geo
Redundancy feature.
Release 5.2.2This feature was introduced.BNG Geo Redundancy
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Where DocumentedChanged in ReleaseDescriptionFeature
Establishing Subscriber
Sessions chapter:
•Packet-triggered Routed
Subscriber Sessions, on
page 89
Refer IPoE Commands chapter
in Cisco ASR 9000 Series
Aggregation Services Router
Broadband Network Gateway
Command Reference, for
information on the commands
used for Packet-triggered
Routed Subscriber Sessions
feature.
Release 5.2.2This feature was introduced.Packet-triggered Routed
Subscriber Sessions
Establishing Subscriber
Sessions chapter:
•QoS on BNG Pseudowire
Headend, on page 173
Release 5.2.2QoS support was added for
BNG Pseudowire Headend
QoS on BNG Pseudowire
Headend
Configuring Subscriber
Features chapter:
•Randomization of Interim
Timeout of Sessions or
Services, on page 276
Refer Subscriber Commands
chapter in Cisco ASR 9000
Series Aggregation Services
Router Broadband Network
Gateway Command Reference,
for information on the
commands used for this feature.
Release 5.2.2New command was introduced
to support randomization of
interim timeout of subscriber
sessions or services
Randomization of Interim
Timeout of Subscriber Sessions
or Services
Broadband Network Gateway
Overview chapter:
•Hardware Requirements
for BNG, on page 11
Release 5.2.2BNG support was extended to
new line cards
Support for New Line Cards
Establishing Subscriber
Sessions chapter:
•BNG over Pseudowire
Headend , on page 173
Release 5.2.0This feature was introduced.BNG over Pseudowire Headend
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New and Changed BNG Features
New and Changed BNG Feature Information
Where DocumentedChanged in ReleaseDescriptionFeature
Establishing Subscriber
Sessions chapter:
•eBGP over PPPoE, on
page 172
Release 5.2.0This feature was introduced.eBGP over PPPoE
Configuring Authentication,
Authorization and Accounting
Functions chapter:
•Multi-Action Change of
Authorization, on page
45
Refer Control Policy
Commands and Subscriber
Commands chapters in Cisco
ASR 9000 Series Aggregation
Services Router Broadband
Network Gateway Command
Reference, for information on
the commands used for
MA-CoA feature.
Release 5.2.0This feature was introduced.Multi-Action Change of
Authorization (MA-CoA)
Configuring Subscriber
Features chapter:
•Outer VLAN Range, on
page 239
Refer BNG Interface
Commands chapter in Cisco
ASR 9000 Series Aggregation
Services Router Broadband
Network Gateway Command
Reference, for information on
the commands used for Outer
VLAN Range feature.
Release 5.2.0This feature was introduced.Outer VLAN Range
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New and Changed BNG Feature Information
Where DocumentedChanged in ReleaseDescriptionFeature
Deploying the Quality of
Service (QoS) chapter:
•RADIUS Based Policing
- QoS Shaper
Parameterization, on page
193
Refer Control Policy
Commands chapter in Cisco
ASR 9000 Series Aggregation
Services Router Broadband
Network Gateway Command
Reference, for information on
the commands used for QoS
Shaper Parameterization
feature.
Release 5.2.0This feature was introduced.QoS Shaper Parameterization
Configuring Authentication,
Authorization and Accounting
Functions chapter:
•User Authentication and
Authorization in the Local
Network, on page 50
Release 5.2.0This feature was introduced.User Authentication and
Authorization in the Local
Network
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CHAPTER 2
Broadband Network Gateway Overview
This chapter provides an overview of the Broadband Network Gateway (BNG) functionality implemented
on the Cisco ASR 9000 Series Router.
Table 2: Feature History for Broadband Network Gateway Overview
ModificationRelease
Initial release of BNG.Release 4.2.0
•Understanding BNG, page 5
•BNG Architecture, page 6
•BNG Role in ISP Network Models, page 8
•BNG Packaging, page 9
•BNG Configuration Process, page 11
•Hardware Requirements for BNG, page 11
•BNG Interoperability, page 12
•BNG Smart Licensing, page 13
Understanding BNG
Broadband Network Gateway (BNG) is the access point for subscribers, through which they connect to the
broadband network. When a connection is established between BNG and Customer Premise Equipment (CPE),
the subscriber can access the broadband services provided by the Network Service Provide (NSP) or Internet
Service Provider (ISP).
BNG establishes and manages subscriber sessions. When a session is active, BNG aggregates traffic from
various subscriber sessions from an access network, and routes it to the network of the service provider.
BNG is deployed by the service provider and is present at the first aggregation point in the network, such as
the edge router. An edge router, like the Cisco ASR 9000 Series Router, needs to be configured to act as the
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BNG. Because the subscriber directly connects to the edge router, BNG effectively manages subscriber access,
and subscriber management functions such as:
•Authentication, authorization and accounting of subscriber sessions
•Address assignment
•Security
•Policy management
•Quality of Service (QoS)
Some benefits of using BNG are:
•The BNG router not only performs the routing function but also communicates with authentication,
authorization, and accounting (AAA) server to perform session management and billing functions. This
makes the BNG solution more comprehensive.
•Different subscribers can be provided different network services. This enables the service provider to
customize the broadband package for each customer based on their needs.
BNG Architecture
The goal of the BNG architecture is to enable the BNG router to interact with peripheral devices (like CPE)
and servers (like AAA and DHCP), in order to provide broadband connectivity to subscribers and manage
subscriber sessions. The basic BNG architecture is shown in this figure.
Figure 1: BNG Architecture
The BNG architecture is designed to perform these tasks:
•Connecting with the Customer Premise Equipment (CPE) that needs to be served broadband services.
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•Establishing subscriber sessions using IPoE or PPPoE protocols.
•Interacting with the AAA server that authenticates subscribers, and keeps an account of subscriber
sessions.
•Interacting with the DHCP server to provide IP address to clients.
The four BNG tasks are briefly explained in the following sections.
Connecting with the CPE
BNG connects to the CPE through a multiplexer and Home Gateway (HG). The CPE represents the triple
play service in telecommunications, namely, voice (phone), video (set top box), and data (PC). The individual
subscriber devices connect to the HG. In this example, the subscriber connects to the network over a Digital
Subscriber Line (DSL) connection. Therefore, the HG connects into a DSL Access Multiplexer (DSLAM).
Multiple HGs can connect to a single DSLAM that sends the aggregated traffic to the BNG router. The BNG
router routes traffic between the broadband remote access devices (like DSLAM or Ethernet Aggregation
Switch) and the service provider network.
Establishing Subscriber Sessions
Each subscriber (or more specifically, an application running on the CPE) connects to the network by a logical
session. Based on the protocol used, subscriber sessions are classified into two types:
•PPPoE subscriber session—The PPP over Ethernet (PPPoE) subscriber session is established using the
point-to-point (PPP) protocol that runs between the CPE and BNG.
•IPoE subscriber session—The IP over Ethernet (IPoE) subscriber session is established using IP protocol
that runs between the CPE and BNG; IP addressing is done using the DHCP protocol.
Interacting with the RADIUS Server
BNG relies on an external Remote Authentication Dial-In User Service (RADIUS) server to provide subscriber
Authentication, Authorization, and Accounting (AAA) functions. During the AAA process, BNG uses RADIUS
to:
•authenticate a subscriber before establishing a subscriber session
•authorize the subscriber to access specific network services or resources
•track usage of broadband services for accounting or billing
The RADIUS server contains a complete database of all subscribers of a service provider, and provides
subscriber data updates to the BNG in the form of attributes within RADIUS messages. BNG, on the other
hand, provides session usage (accounting) information to the RADIUS server. For more information about
RADIUS attributes, see RADIUS Attributes, on page 307.
BNG supports connections with more than one RADIUS server to have fail over redundancy in the AAA
process. For example, if RADIUS server A is active, then BNG directs all messages to the RADIUS server
A. If the communication with RADIUS server A is lost, BNG redirects all messages to RADIUS server B.
During interactions between the BNG and RADIUS servers, BNG performs load balancing in a round-robin
manner. During the load balancing process, BNG sends AAA processing requests to RADIUS server A only
if it has the bandwidth to do the processing. Else, the request is send to RADIUS server B.
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Interacting with the DHCP Server
BNG relies on an external Dynamic Host Configuration Protocol (DHCP) server for address allocation and
client configuration functions. BNG can connect to more than one DHCP server to have fail over redundancy
in the addressing process. The DHCP server contains an IP address pool, from which it allocates addresses
to the CPE.
During the interaction between BNG and the DHCP server, BNG acts as a DHCP relay or DHCP proxy.
As the DHCP relay, BNG receives DHCP broadcasts from the client CPE, and forwards the request to the
DHCP server.
As the DHCP proxy, BNG itself maintains the address pool by acquiring it from DHCP server, and also
manages the IP address lease. BNG communicates on Layer 2 with the client Home Gateway, and on Layer
3 with the DHCP server.
The DSLAM modifies the DHCP packets by inserting subscriber identification information. BNG uses the
identification information inserted by the DSLAM, as well as the address assigned by the DHCP server, to
identify the subscriber on the network, and monitor the IP address lease.
BNG Role in ISP Network Models
The role of BNG is to pass traffic from the subscriber to the ISP. The manner in which BNG connects to the
ISP depends on the model of the network in which it is present. There are two types of network models:
•Network Service Provider, on page 8
•Access Network Provider, on page 9
Network Service Provider
The following figure shows the topology of a Network Service Provider model.
Figure 2: Network Service Provider Model
In the Network Service Provider model, the ISP (also called the retailer) directly provides the broadband
connection to the subscriber. As shown in the above figure, BNG is at the edge router, and its role is to connect
to the core network through uplinks.
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