RADIUS Logical Line ID

Last Updated: January 17, 2012

The RADIUS Logical Line ID feature, also known as the Logical Line Identification (LLID) Blocking feature enables administrators to track their customers on the basis of the physical lines on which customer calls originate. Administrators use a virtual port that does not change as customers move from one physical line to another. This virtual port facilitates the maintenance of the administrator's customer profile database and allows the administrator to do additional security checks on customers.

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 RADIUS Logical Line ID

Although this feature can be used with any RADIUS server, some RADIUS servers may require modifications to their dictionary files to allow the Calling-Station-ID attribute to be returned in Access-Accept messages. For example, the Merit RADIUS server does not support LLID downloading unless you modify its dictionary as follows: "ATTRIBUTE Calling-Station-Id 31 string (*, *)"

Restrictions for RADIUS Logical Line ID

The RADIUS Logical Line ID feature supports RADIUS only. TACACS+ is not supported.

This feature can be applied only toward PPP over Ethernet over ATM (PPPoEoATM) and PPP over Ethernet over VLAN (PPPoEoVLAN) (Dot1Q) calls; no other calls, such as ISDN, can be used.

Information About RADIUS Logical Line ID

Preauthorization

LLID is an alphanumeric string (which must be a minimum of one character and a maximum of 253 characters) that is a logical identification of a subscriber line. LLID is maintained in a customer profile database on a RADIUS server. When the customer profile database receives a preauthorization request from the access router, the RADIUS server sends the LLID to the router as the Calling-Station-ID attribute (attribute 31).

The Layer 2 Tunneling Protocol (L2TP) access concentrator (LAC) sends a preauthorization request to the customer profile database when the LAC is configured for preauthorization. Configure the LAC for preauthorization using the subscriber access command.


Note
Downloading the LLID is referred to as "preauthorization" because it occurs before either service (domain) authorization or user authentication and authorization occur.

The customer profile database on the RADIUS server consists of user profiles for each physical network access server (NAS) port that is connected to the router. Each user profile contains a profile matched to a username (attribute 1) representing the physical port on the router. When the router is configured for preauthorization, it queries the customer profile database using a username representative of the physical NAS port making the connection to the router. When a match is found in the customer profile database, the customer profile database returns an Access-Accept message containing the LLID in the user profile. The LLID is defined in the Access-Accept record as the Calling-Station-ID attribute.

The preauthorization process can also provide the real username being used for authentication to the RADIUS server. Because the physical NAS port information is being used as the username (attribute 1), RADIUS attribute 77 (Connect-Info) can be configured to contain the authentication username. This configuration allows the RADIUS server to provide additional validation on the authorization request if it chooses, such as analyzing the username for privacy rules, before returning an LLID back to the router.

How to Configure RADIUS Logical Line ID

Configuring Preauthorization

To download the LLID and configure the LAC for preauthorization, perform the following steps.

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    ip radius source-interface interface-name

4.    subscriber access {pppoe | pppoa} pre-authorize nas-port-id [default | list-name] [send username]


DETAILED STEPS
  Command or Action Purpose
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
ip radius source-interface interface-name


Example:



Example:

Router (config)# ip radius source-interface Loopback1

 

Specifies the IP address portion of the username for the preauthorization request.

 
Step 4
subscriber access {pppoe | pppoa} pre-authorize nas-port-id [default | list-name] [send username]


Example:



Example:

Router (config)# subscriber access pppoe pre-authorize nas-port-id mlist_llid send username

 

Enables the LLID to be downloaded so the router can be configured for preauthorization.

The send username option specifies that you include the authentication username of the session inside the Connect-Info (attribute 77) in the Access-Request message.

 

Configuring the LLID in a RADIUS User Profile

To configure the user profile for preauthorization, add a NAS port user to the customer profile database and add RADIUS Internet Engineering Task Force (IETF) attribute 31 (Calling-Station-ID) to the user profile.

SUMMARY STEPS

1.    UserName=nas_port: ip-address:slot/module/port/vpi.vci

2.    User-Name=nas-port: ip-address:slot/module/port/vlan-id

3.    Calling-Station-Id = "string (*,*)"


DETAILED STEPS
  Command or Action Purpose
Step 1
UserName=nas_port: ip-address:slot/module/port/vpi.vci 

(Optional) Adds a PPPoE over ATM NAS port user.

 
Step 2
User-Name=nas-port: ip-address:slot/module/port/vlan-id 

(Optional) Adds a PPPoE over VLAN NAS port user.

 
Step 3
Calling-Station-Id = "string (*,*)" 

Adds attribute 31 to the user profile.

  • String--One or more octets, containing the phone number from which the user placed the call.
 

Verifying Logical Line ID

To verify feature functionality, perform the following steps.

SUMMARY STEPS

1.    enable

2.    debug radius


DETAILED STEPS
  Command or Action Purpose
Step 1
enable


Example:

Router> enable

 

Enables privileged EXEC mode.

  • Enter your password if prompted.
 
Step 2
debug radius


Example:

Router# debug radius

 

Checks to see that RADIUS attribute 31 is the LLID in the Accounting-Request on LAC and in the Access-Request and Accounting-Request on the LNS.

 

Configuration Examples for RADIUS Logical Line ID

LAC for Preauthorization Configuration Example

The following example shows how to configure your LAC for preauthorization by downloading the LLID:

aaa new-model
aaa group server radius sg_llid
 server 172.31.164.106 auth-port 1645 acct-port 1646
aaa group server radius sg_water
 server 172.31.164.106 auth-port 1645 acct-port 1646
aaa authentication ppp default group radius 
aaa authorization confg-commands
aaa authorization network default group sg_water
aaa authorization network mlist_llid group sg_llid
aaa session-id common
!
username s7200_2 password 0 lab
username s5300 password 0 lab
username sg_water password 0 lab
vpdn enable
!
vpdn-group 2 
 request-dialin 
 protocol l2tp 
 domain example.com 
 domain example.com#184 
 initiate-to ip 10.1.1.1 
 local name s7200_2 
 l2tp attribute clid mask-method right * 255 match #184
!
vpdn-group 3
 accept dialin
  protocol pppoe
  virtual-template 1
!
! 
Enable the LLID to be downloaded.
subscriber access pppoe pre-authorize nas-port-id mlist_llid send username
!
interface Loopback0
 ip address 10.1.1.2 255.255.255.0
!
interface Loopback1
 ip address 10.1.1.1 255.255.255.0
!
interface FastEthernet1/0/0
 ip address 10.1.1.8 255.255.255.0 secondary
 ip address 10.0.58.111 255.255.255.0 
 no cdp enable
!
interface ATM4/0/0
 no ip address
 no atm ilmi-keepalive
!
interface ATM4/0/0.1 point-to-point
 pvc 1/100
  encapsulation aa15snap
  protocol pppoe
!
interface virtual-template1
 no ip unnumbered Loopback0
 no peer default ip address
 ppp authentication chap
!
radius-server host 172.31.164.120 auth-port 1645 acct-port 1646 key rad123
radius-server host 172.31.164.106 auth-port 1645 acct-port 1646 key rad123
ip radius source-interface Loopback1

RADIUS User Profile for LLID Example

The following example shows how to configure the user profile for LLID querying for PPPoEoVLAN and PPPoEoATM and how to add attribute 31:

pppoeovlan
----------
nas-port:10.1.0.3:6/0/0/0    Password = "password1",
    Service-Type = Outbound,
    Calling-Station-ID = "cat-example"
pppoeoa
--------
nas-port:10.1.0.3:6/0/0/1.100    Password = "password1",
    Service-Type = Outbound,
    Calling-Station-ID = "cat-example"

Additional References

Related Documents

Related Topic

Document Title

Cisco IOS commands

Cisco IOS Master Commands List, All Releases

Security commands: complete command syntax, command modes, command history, defaults, usage guidelines, and examples

Cisco IOS Security Command Reference

AAA authentication

Configuring Authentication feature module.

Attribute screening for access requests

RADIUS Attribute Value Screening feature module.

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Feature Information for RADIUS Logical Line ID

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 1 Feature Information for RADIUS Logical Line ID

Feature Name

Releases

Feature Information

RADIUS Logical Line ID

Cisco IOS XE Release 2.1

The RADIUS Logical Line ID feature, also known as the Logical Line Identification (LLID) Blocking feature enables administrators to track their customers on the basis of the physical lines on which customer calls originate.

In Cisco IOS XE Release 2.1, this feature was introduced on Cisco ASR 1000 Series Aggregation Services Routers.

The following command was introduced or modified by this feature: subscriber access.

Calling Station ID Attribute 31

Cisco IOS XE Release 2.1

This feature was introduced on Cisco ASR 1000 Series Routers.

LLID Blocking

Cisco IOS XE Release 2.1

This feature was introduced on Cisco ASR 1000 Series Routers.

Glossary

LLID Blocking --A feature that enables administrators to track their customers on the basis of the physical lines on which the calls of the customers originate. Also known as RADIUS Logical Line ID.

RADIUS Logical Line ID --A feature that enables administrators to track their customers on the basis of the physical lines on which the calls of the customers originate. Also known as LLID Blocking.

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.

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