Broadband Access Aggregation and DSL Configuration Guide, Cisco IOS Release 12.4T
Configuring the Physical Subscriber Line for RADIUS Access and Accounting
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Configuring the Physical Subscriber Line for RADIUS Access and Accounting

Last Updated: December 5, 2011

Configuring a physical subscriber line for RADIUS Access and Accounting enables an L2TP access concentrator (LAC) and an L2TP network server (LNS) to forward RADIUS NAS-Port and NAS-Port-Type attribute values for PPP over ATM, PPPoE over ATM, and PPPoE over IEEE 802.1Q VLANs.

Finding Feature Information

Your software release may not support all the features documented in this module. For the latest feature information and caveats, see the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the Feature Information Table at the end of this document.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to www.cisco.com/go/cfn. An account on Cisco.com is not required.

Prerequisites for Configuring the Physical Subscriber Line for RADIUS Access and Accounting

  • RADIUS port identification for PPP requires the PPP extended NAS-Port format.
  • You must perform the configuration procedures in the "Configuring RADIUS" chapter in the Cisco IOS Security Configuration Guide.
  • You must perform the PPP over ATM configuration procedures in the "Providing Protocol Support for Broadband Access Aggregation of PPP over ATM Sessions" module.
  • You must perform the PPPoE configuration procedures in the "Providing Protocol Support for Broadband Access Aggregation of PPPoE Sessions" module.

Note
The PPP extended NAS-Port format increases the size of the NAS-Port attribute field to 32 bits and changes the NAS-Port attribute format to provide the RADIUS server with details about the ATM port, the virtual path identifier (VPI), the virtual channel identifier (VCI), and, for IEEE 802.1Q VLANs, the VLAN ID.

Information About Configuring the Physical Subscriber Line for RADIUS Access and Accounting

PPP over ATM and PPPoE over ATM NAS-Port Attribute Field Format

For PPP over ATM and PPP over ATM, the PPP extended format enables the NAS-Port attribute field to provide details about the ATM interface, VPI, and VCI. The figure below shows the format of the NAS-Port attribute field when the PPP extended NAS-Port format is configured and PPPoA over ATM or PPPoE over ATM is being used.

Figure 1Format of the NAS-Port Attribute Field for PPP over ATM and PPPoE over ATM


The interfaces, VPI, and VCI correspond to the interface and virtual circuit (VC) on which the ppp session entered the router.


Note
For Cisco 6400 series routers, the interface, VPI, and VCI correspond to the interface and VC on which the session entered the Cisco 6400 node switch processor (NSP).

The figure below shows the format of the 8-bit interface field. For platforms that do not have slots or modules, the slot and module fields is 0.

Figure 2Format of the Interface Field for PPP over ATM and PPPoE over ATM


The NAS-Port-Type value for PPP over ATM and PPPoE over ATM is 5, which is the value for virtual port types.

PPPoE over IEEE 802.1Q VLANs Format

For PPPoE over 802.1Q VLANs, the PPP extended format provides details about the interface and the VLAN ID. The figure below shows the format of the NAS-Port attribute field when the PPP extended NAS-Port format is configured and PPPoE over an IEEE 802.1Q VLAN is being used.

Figure 3Format of the NAS-Port Attribute Field for PPPoE over 802.1Q VLANs


The figure below shows the format of the 8-bit interface field. For platforms that do not have slots or modules, the slot and module fields will be 0.

Figure 4Format of the Interface Field for PPPoE over 802.1Q VLANs


The NAS-Port-Type value for PPPoE over 802.1Q VLANs is 15.

How to Configure the Physical Subscriber Line for RADIUS Access and Accounting

Configuring the LAC for RADIUS Port Identification for PPP

Perform this task to configure the LAC for RADIUS port identification for PPP.

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    radius-server attribute nas-port format d

4.    end


DETAILED STEPS
 Command or ActionPurpose
Step 1
enable


Example:

Router> enable

 

Enables privileged EXEC mode.

  • Enter your password if prompted.
 
Step 2
configure terminal


Example:

Router# configure terminal

 

Enters global configuration mode.

 
Step 3
radius-server attribute nas-port format d


Example:

Router(config)# radius-server attribute nas-port format d

 

Specifies that PPP extended NAS-Port format that is used for RADIUS accounting.

 
Step 4
end


Example:

Router(config-bba-group)# end

 

Ends the configuration session and returns to privileged EXEC mode.

 

Configuring the LNS for RADIUS Port Identification for PPP

Perform this task to configure the LNS for RADIUS port identification for PPP.


Note
In order for the LNS to forward PPP extended NAS-Port format values to the RADIUS server, both the LAC and the LNS must be Cisco routers running a Cisco IOS image that supports RADIUS port identification for PPP.
SUMMARY STEPS

1.    enable

2.    configure terminal

3.    radius-server attribute nas-port format d

4.    vpdn aaa attribute nas-port vpdn-nas

5.    end


DETAILED STEPS
 Command or ActionPurpose
Step 1
enable


Example:

Router> enable

 

Enables privileged EXEC mode.

  • Enter your password if prompted.
 
Step 2
configure terminal


Example:

Router# configure terminal

 

Enters global configuration mode.

 
Step 3
radius-server attribute nas-port format d


Example:

Router(config)# radius-server attribute nas-port format d

 

Specifies that PPP extended NAS-Port format that is used for RADIUS accounting.

 
Step 4
vpdn aaa attribute nas-port vpdn-nas


Example:

Router(config)# vpdn aaa attribute nas-port vpdn-nas

 

Enables the LNS to send PPP extended NAS-Port format values to the RADIUS server for accounting.

 
Step 5
end


Example:

Router(config-bba-group)# end

 

Ends the configuration session and returns to privileged EXEC mode.

 

Configuration Examples for Identifying the Physical Subscriber Line

RADIUS Port Identification for PPPoE over ATM Example

The following example shows the configuration of the PPP extended NAS-Port format on an LAC using PPPoE over ATM:

vpdn enable 
! 
vpdn-group 1 
 request-dialin 
 protocol l2tp

domain vpn1 

initiate-to ip 10.12.1.64  priority 1 
 local name NAS1-1 
! 
virtual-template 1 pre-clone 20 
virtual-template 2 pre-clone 20 
!
! 
bba-group pppoe vpn1 
 virtual-template 1 
 sessions per-vc limit 2 
 sessions per-mac limit 1 
!

!

interface ATM4/0.1 multipoint
 pvc 1/33
 encapsulation aal5snap
 protocol pppoe group vpn1
!
!
aaa new-model
aaa authentication ppp default local group radius
aaa authorization network default local group radius
aaa accounting network default start-stop group radius
radius-server host 172.69.69.66 auth-port 1645 acct-port 1646
radius-server retransmit 3
radius-server attribute nas-port format d
radius-server key rad123

!

RADIUS Port Identification for PPPoE over an 802.1Q VLAN Example

The following example shows the configuration of the PPP extended NAS-Port format on an LAC running PPPoE over an 802.1Q VLAN:

bba-group pppoe global 
 virtual-template 1 
 sessions max limit 8000 
 sessions per-vc limit 8

sessions per-mac limit 2 

! 
bba-group pppoe vpn1 
 virtual-template 1 
 sessions per-vc limit 2 
 sessions per-mac limit 1 
! 
bba-group pppoe vpn2 
 virtual-template 2 
 sessions per-vc limit 2 
 sessions per-mac limit 1 ! 
vc-class atm class-pppoe-global 
 protocol pppoe 
! !
interface FastEthernet2/0.2
 encapsulation dot1Q 2
 pppoe enable group vpn1
!
interface FastEthernet2/0.3
 encapsulation dot1Q 3
 pppoe enable group vpn2
!

aaa new-model

aaa authentication ppp default local group radius
aaa authorization network default local group radius
aaa accounting network default start-stop group radius
radius-server host 172.69.69.66 auth-port 1645 acct-port 1646
radius-server retransmit 3
radius-server attribute nas-port format d

radius-server key rad123

LNS Configuration for RADIUS Port Identification for PPP Example

In the following example, the LNS is configured to recognize and forward PPP extended NAS-Port format values to the RADIUS server. The PPP extended NAS-Port format must also be configured on the LAC for this configuration to be effective.

vpdn enable
no vpdn logging
!
vpdn-group L2TP-tunnel
 accept-dialin
 protocol l2tp
 virtual-template 1
 terminate-from hostname lac1
 local name lns1
!         
!
aaa new-model
aaa authentication ppp default local group radius
aaa authorization network default local group radius
aaa accounting network default start-stop group radius
radius-server host 172.79.79.76 auth-port 1645 acct-port 1646
radius-server retransmit 3
radius-server attribute nas-port format d
radius-server key lns123
!

vpdn aaa attribute nas-port vpdn-nas

Additional References

The following sections provide references related to the Identifying the Physical Subscriber Line for RADIUS Access and Accounting feature.

Related Documents

Related Topic

Document Title

Configuring PPP over ATM sessions

"Providing Protocol Support for Broadband Access Aggregation of PPP over ATM Sessions" module

Configuring PPPoE sessions

"Providing Protocol Support for Broadband Access Aggregation of PPPoE Sessions" module

RADIUS configuration

"Configuring RADIUS" module of theCisco IOS Security Configuration Guide

RADIUS attributes

"RADIUS Attributes" appendix to the Cisco IOS Security Configuration Guide

Tunneling configuration

"Configuring Virtual Private Networks" module of the Cisco IOS Dial Technologies Configuration Guide

Standards

Standard

Title

No new or modified standards are supported by this feature.

--

MIBs

MIB

MIBs Link

No new or modified MIBs are supported by this feature.

To locate and download MIBs for selected platforms, Cisco IOS releases, and feature sets, use Cisco MIB Locator found at the following URL:

http://www.cisco.com/go/mibs

RFCs

RFC

Title

None

--

Technical Assistance

Description

Link

The Cisco Support website provides extensive online resources, including documentation and tools for troubleshooting and resolving technical issues with Cisco products and technologies.

To receive security and technical information about your products, you can subscribe to various services, such as the Product Alert Tool (accessed from Field Notices), the Cisco Technical Services Newsletter, and Really Simple Syndication (RSS) Feeds.

Access to most tools on the Cisco Support website requires a Cisco.com user ID and password.

http://www.cisco.com/techsupport

Feature Information for Identifying the Physical Subscriber Line for RADIUS Access and Accounting

The following table provides release information about the feature or features described in this module. This table lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to www.cisco.com/go/cfn. An account on Cisco.com is not required.

Table 1Feature Information for Identifying the Physical Subscriber Line for RADIUS Access and Accounting

Feature Name

Releases

Feature Information

RADIUS Port Identification

12.2(1) 12.2(33)SRC

Configuring RADIUS port identification for PPP enables an L2TP access concentrator (LAC) and an L2TP network server (LNS) to identify and forward RADIUS NAS-Port and NAS-Port-type attribute values for PPP over ATM, PPPoE over ATM, and PPPoE over IEEE 802.1Q VLANs.

In 12.2(1), this feature was introduced.

In 12.2(33)SRC, this feature was integrated into the SRC release.

Cisco and the Cisco logo are trademarks or registered trademarks of Cisco and/or its affiliates in the U.S. and other countries. To view a list of Cisco trademarks, go to this URL: www.cisco.com/go/trademarks. Third-party trademarks mentioned are the property of their respective owners. The use of the word partner does not imply a partnership relationship between Cisco and any other company. (1110R)

Any Internet Protocol (IP) addresses and phone numbers used in this document are not intended to be actual addresses and phone numbers. Any examples, command display output, network topology diagrams, and other figures included in the document are shown for illustrative purposes only. Any use of actual IP addresses or phone numbers in illustrative content is unintentional and coincidental.

© 2011 Cisco Systems, Inc. All rights reserved.