Table Of Contents
Enabling PPPoE Relay Discovery and Service Selection Functionality
Contents
Prerequisites for Enabling PPPoE Relay Discovery and Service Selection Functionality
Information About Enabling PPPoE Relay Discovery and Service Selection Functionality
L2TP Active Discovery Relay for PPPoE
How to Enable PPPoE Relay Discovery and Service Selection Functionality
Configuring the LAC and Tunnel Switch for PPPoE Relay
RADIUS Subscriber Profile Entry for the LAC
What to Do Next
Configuring the LNS (or Multihop Node) to Respond to Relayed PAD Messages
RADIUS VPDN Group User Profile Entry for the LNS
Monitoring PPPoE Relay
Troubleshooting Tips
Configuration Examples for Enabling PPPoE Relay Discovery and Service Selection Functionality
PPPoE Relay on LAC Configuration: Example
Basic LNS Configured for PPPoE Relay: Example
Tunnel Switch (or Multihop Node) Configured to Respond to PAD Messages: Example
Tunnel Switch Configured to Relay PAD Messages: Example
RADIUS Subscriber Profile Entry for the LAC: Example
RADIUS VPDN Group User Profile Entry for the LNS: Example
Additional References
Related Documents
Standards
MIBs
RFCs
Technical Assistance
Feature Information for Enabling PPPoE Relay Discovery and Service Selection Functionality
Enabling PPPoE Relay Discovery and Service Selection Functionality
The PPPoE Relay feature enables an L2TP access concentrator (LAC) to relay active discovery and service selection functionality for PPP over Ethernet (PPPoE), over a Layer 2 Tunneling Protocol (L2TP) control channel, to an L2TP network server (LNS) or tunnel switch (multihop node). The relay functionality of this feature allows the LNS or tunnel switch to advertise the services it offers to the client, thereby providing end-to-end control of services between the LNS and a PPPoE client.
Module History
This module was first published on May 2, 2005, and last updated on May 2, 2005.
Finding Feature Information in This Module
Not all features may be supported in your Cisco IOS software release. Use the "Feature Information for Enabling PPPoE Relay Discovery and Service Selection Functionality" section to find information about feature support and configuration.
Contents
•
Prerequisites for Enabling PPPoE Relay Discovery and Service Selection Functionality
•
Information About Enabling PPPoE Relay Discovery and Service Selection Functionality
•
How to Enable PPPoE Relay Discovery and Service Selection Functionality
•
Configuration Examples for Enabling PPPoE Relay Discovery and Service Selection Functionality
•
Additional References
•
Feature Information for Enabling PPPoE Relay Discovery and Service Selection Functionality
Prerequisites for Enabling PPPoE Relay Discovery and Service Selection Functionality
•
You must understand the concepts described in the "Preparing for Broadband Access Aggregation" module.
•
PPPoE sessions must be established using the procedures in the "Providing Protocol Support for Broadband Access Aggregation of PPPoE Sessions" module.
•
This document assumes you understand how to configure a virtual private dialup network (VPDN) tunnel and a tunnel switch. See the "Related Documents" section for more information about these features.
Information About Enabling PPPoE Relay Discovery and Service Selection Functionality
To configure PPPoE relay, you need to understand the following concept:
•
L2TP Active Discovery Relay for PPPoE
L2TP Active Discovery Relay for PPPoE
The PPPoE protocol described in RFC 2516 defines a method for active discovery and service selection of devices in the network by an LAC. A PPPoE client uses these methods to discover an access concentrator in the network, and the access concentrator uses these methods to advertise the services it offers.
The PPPoE Relay feature introduced in Cisco IOS Release 12.3(4)T allows the active discovery and service selection functionality to be offered by the LNS, rather than just by the LAC. The PPPoE Relay feature implements the Network Working Group Internet-Draft titled L2TP Active Discovery Relay for PPPoE. The Internet-Draft describes how to relay PPPoE Active Discovery (PAD) and Service Relay Request (SRRQ) messages over an L2TP control channel (the tunnel). (See the "RFCs" section for information on how to access Network Working Group Internet-Drafts.)
The key benefit of the PPPoE Relay feature is end-to-end control of services between the LNS and a PPPoE client.
How to Enable PPPoE Relay Discovery and Service Selection Functionality
This section contains the following procedures:
•
Configuring the LAC and Tunnel Switch for PPPoE Relay (required)
•
Configuring the LNS (or Multihop Node) to Respond to Relayed PAD Messages (required)
•
Additional References (optional)
Configuring the LAC and Tunnel Switch for PPPoE Relay
Perform this task to configure the LAC and tunnel switch for PPPoE Relay, which configures a subscriber profile that directs PAD messages to be relayed on an L2TP tunnel. The subscriber profile also will contain an authorization key for the outgoing L2TP tunnel.
SUMMARY STEPS
1.
enable
2.
configure terminal
3.
subscriber profile profile-name
4.
service relay pppoe vpdn group vpdn-group-name
5.
exit
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
|
subscriber profile profile-name
Example:
Router(config)# subscriber profile profile-1
|
Configures the subscriber profile name and enters subscriber profile configuration mode.
• profile-name—Is referenced from a PPPoE profile configured by the bba-group pppoe global configuration command, so that all the PPPoE sessions using the PPPoE profile defined by the bba-group pppoe command will be treated according to the defined subscriber profile.
|
Step 4
|
service relay pppoe vpdn group vpdn-group-name
Example:
Router(config-sss-profile)# service relay pppoe
vpdn group Group-A
|
Provides PPPoE relay service using a VPDN L2TP tunnel for the relay. The VPDN group name specified is used to obtain outgoing L2TP tunnel information.
• See the "RADIUS Subscriber Profile Entry for the LAC" section for the equivalent RADIUS profile entry.
|
Step 5
|
exit
Example:
Router(config-sss-profile)# exit
|
(Optional) Ends the configuration session and returns to privileged EXEC mode.
|
RADIUS Subscriber Profile Entry for the LAC
The following example shows how to enter Subscriber Service Switch subscriber service attributes in a AAA RADIUS server profile.
Cisco:Cisco-Avpair = "sss:sss-service=relay-pppoe"
What to Do Next
Configure the LNS side of the configuration by performing the tasks described in the "Configuring the LNS (or Multihop Node) to Respond to Relayed PAD Messages" section.
Configuring the LNS (or Multihop Node) to Respond to Relayed PAD Messages
On the router that responds to relayed PAD messages, perform this task to configure a PPPoE group and attach it to a VPDN group that accepts dial-in calls for L2TP. The relayed PAD messages will be passed from the VPDN L2TP tunnel and session to the PPPoE broadband group for receiving the PAD responses.
SUMMARY STEPS
1.
enable
2.
configure terminal
3.
vpdn-group vpdn-group-name
4.
accept-dialin
5.
protocol l2tp
6.
virtual-template template-number
7.
exit
8.
terminate-from hostname host-name
9.
relay pppoe bba-group pppoe-bba-group-name
10.
exit
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
|
vpdn-group vpdn-group-name
Example:
Router(config)# vpdn-group Group-A
|
Creates a VPDN group and enters VPDN group configuration mode.
|
Step 4
|
accept-dialin
Example:
Router(config-vpdn)# accept-dialin
|
Configures the LNS to accept tunneled PPP connections from an LAC and creates an accept-dialin VPDN subgroup.
|
Step 5
|
protocol l2tp
Example:
Router(config-vpdn-req-in)# protocol l2tp
|
Specifies the L2TP tunneling protocol.
|
Step 6
|
virtual-template template-number
Example:
Router(config-vpdn-req-in)# virtual-template 2
|
Specifies which virtual template will be used to clone virtual access interfaces.
|
Step 7
|
exit
Example:
Router(config-vpdn-req-in)# exit
|
Exits to VPDN group configuration mode.
|
Step 8
|
terminate-from hostname host-name
Example:
Router(config-vpdn)# terminate-from hostname LAC-1
|
Specifies the LAC hostname that will be required when the VPDN tunnel is accepted.
|
Step 9
|
relay pppoe bba-group pppoe-bba-group-name
Example:
Router(config-vpdn)# relay pppoe bba-group group-2
|
Specifies the PPPoE BBA group that will respond to the PAD messages.
• The PPPoE BBA group name is defined with the bba-group pppoe group-name global configuration command.
• See the "RADIUS VPDN Group User Profile Entry for the LNS" section for the equivalent RADIUS profile entry.
|
Step 10
|
exit
Example:
Router(config-vpdn)# exit
|
Exits to global configuration mode.
|
RADIUS VPDN Group User Profile Entry for the LNS
The following example shows how to enter the VPDN group attributes in a AAA RADIUS server profile.
Cisco:Cisco-Avpair = "vpdn:relay-pppoe-bba-group=group-name"
Monitoring PPPoE Relay
Perform this task to monitor PPPoE Relay.
SUMMARY STEPS
1.
enable
2.
show pppoe session
3.
show pppoe relay context all
4.
clear pppoe relay context
DETAILED STEPS
| |
Command or Action
|
Purpose
|
Step 1
|
enable
Example:
Router> enable
|
Enables privileged EXEC mode.
• Enter your password if prompted.
|
Step 2
|
show pppoe session
Example:
Router# show pppoe session
|
Displays information about currently active PPPoE sessions.
|
Step 1
enable
Enables privileged EXEC mode.
•
Enter your password if prompted.
Router> enable
Step 2
show pppoe session
Displays information about currently active PPPoE sessions.
Router# show pppoe session
1 session in FORWARDED (FWDED) State
Uniq ID PPPoE RemMAC Port VT VA State
26 19 0001.96da.a2c0 Et0/0.1 5 N/A RELFWD
Step 3
show pppoe relay context all
Displays the PPPoE relay context created for relaying PAD messages.
Router# show pppoe relay context all
Total PPPoE relay contexts 1
UID ID Subscriber-profile State
Step 4
clear pppoe relay context
This command clears the PPPoE relay context created for relaying PAD messages.
Router(config)# clear pppoe relay context
Troubleshooting Tips
Use the following commands in privileged EXEC mode to help you troubleshoot the PPPoE Relay feature:
•
debug ppp forwarding
•
debug ppp negotiation
•
debug pppoe events
•
debug pppoe packets
•
debug vpdn l2x-events
•
debug vpdn l2x-packets
Configuration Examples for Enabling PPPoE Relay Discovery and Service Selection Functionality
This section provides the following configuration examples:
•
PPPoE Relay on LAC Configuration: Example
•
Basic LNS Configured for PPPoE Relay: Example
•
Tunnel Switch (or Multihop Node) Configured to Respond to PAD Messages: Example
•
Tunnel Switch Configured to Relay PAD Messages: Example
•
RADIUS Subscriber Profile Entry for the LAC: Example
•
RADIUS VPDN Group User Profile Entry for the LNS: Example
PPPoE Relay on LAC Configuration: Example
The following is an example of a standard LAC configuration with the commands to enable PPPoE relay added:
username User1 password 0 field
username User2 password 0 field
username user-group password 0 field
username User5 password 0 field
username User2-lac-domain password 0 field
username User1-client-domain@cisco.net password 0 field
username User3-lns-domain password 0 field
vpdn source-ip 10.0.195.151
vpdn-group User2-vpdn-group-domain
initiate-to ip 10.0.195.133
local name User2-lac-domain
ip address 10.22.2.2 255.255.255.0
ip address 10.0.195.151 255.255.255.0
pppoe enable group group_1
interface Virtual-Template1
ip unnumbered Loopback123
ppp chap hostname User2-lac-domain
ip route 0.0.0.0 0.0.0.0 10.0.195.1
subscriber profile Profile1
service relay pppoe vpdn group User2-vpdn-group-domain
Basic LNS Configured for PPPoE Relay: Example
The following example shows the basic configuration for an LNS with commands added for PPPoE relay:
username User5 password 0 field
username user-group password 0 field
username User1 password 0 field
username User2 password 0 field
username User3 password 0 field
username User3-dialout password 0 cisco
username User2-dialout password 0 cisco
username abc password 0 cisco
username dial-7206a password 0 field
username mysgbpgroup password 0 cisco
username User3-lns-domain password 0 field
username User2-lac-domain password 0 field
username User1-client-domain@cisco.net password 0 field
username User5-mh password 0 field
username User1@domain.net password 0 field
vpdn source-ip 10.0.195.133
! Default L2TP VPDN group
initiate-to ip 10.0.195.143
vpdn-group User3-vpdn-group-domain
terminate-from hostname User2-lac-domain
local name User3-lns-domain
relay pppoe group group_1
ip address 10.23.3.2 255.255.255.0
interface FastEthernet0/0
ip address 10.0.195.133 255.255.255.0
interface Virtual-Template2
ip unnumbered Loopback123
ip access-group virtual-access3#234 in
ppp chap hostname User3-lns-domain
ip default-gateway 10.0.195.1
ip route 0.0.0.0 0.0.0.0 10.0.195.1
Tunnel Switch (or Multihop Node) Configured to Respond to PAD Messages: Example
The following is an example of a standard tunnel switch configuration with the commands to enable response to PPPoE relay messages added:
username User1 password 0 room1
username User2 password 0 room1
username User3 password 0 room1
username User1@domain.net password 0 room1
username User3-lns-dnis password 0 cisco
username User3-lns-domain password 0 room1
username User2-lac-dnis password 0 cisco
username User2-lac-domain password 0 room1
username User5 password 0 room1
username User5-mh password 0 room1
username user-group password 0 room1
username User3-dialout password 0 cisco
username User2-dialout password 0 cisco
username abc password 0 cisco
username dial-7206a password 0 room1
username mysgbpgroup password 0 cisco
username User1-client-domain@cisco.net password 0 room1
username User4-lns-domain password 0 room1
terminate-from hostname User5-mh
relay pppoe bba-group group_1
ip address 10.4.4.2 255.255.255.0
ip address 10.3.2.2 255.255.255.0
ip address 10.0.195.143 255.255.0.0
interface Virtual-Template1
ppp chap hostname User3-lns-domain
ip default-gateway 10.0.195.1
ip route 0.0.0.0 0.0.0.0 10.0.195.1
Tunnel Switch Configured to Relay PAD Messages: Example
The following partial example shows a configuration that allows the tunnel switch to relay PAD messages:
subscriber profile profile-1
! Configure profile for PPPoE Relay
service relay pppoe vpdn group Sample1.net
! Configure L2TP tunnel for PPPoE Relay
terminate-from host Host1
relay pppoe bba-group group-1
! Configure L2TP tunnel for PPPoE Relay
! PPPoE-group configured for relay
service profile profile-1
RADIUS Subscriber Profile Entry for the LAC: Example
The following is an example of a typical RADIUS subscriber profile entry for an LAC:
cisco.com Password = "password"
Cisco:Cisco-Avpair = "sss:sss-service=relay-pppoe",
Tunnel-Server-Endpoint = .....,
Tunnel-Client-Auth-ID = "client-id",
Tunnel-Server-Auth-ID = "server-id",
Cisco:Cisco-Avpair = "vpdn:l2tp-tunnel-password=password",
Cisco:Cisco-Avpair = "vpdn:l2tp-nosession-timeout=never",
Tunnel-Assignment-Id = assignment-id
RADIUS VPDN Group User Profile Entry for the LNS: Example
The following is an example of a typical RADIUS subscriber profile entry for an LNS:
cisco.com Password = "password"
Tunnel-Server-Endpoint = .....,
Tunnel-Client-Auth-ID = "client-id",
Tunnel-Server-Auth-ID = "server-id",
Cisco:Cisco-Avpair = "vpdn:l2tp-tunnel-password=password",
Cisco:Cisco-Avpair = "vpdn:l2tp-nosession-timeout=never",
Cisco:Cisco-Avpair = "vpdn:relay-pppoe-bba-group=group-name"
Tunnel-Assignment-Id = assignment-id
Additional References
The following sections provide referenced related to the PPPoE Relay feature.
Related Documents
Standards
MIBs
MIBs
|
MIBs Link
|
None
|
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
RFCs
|
Title
|
RFC 2516
|
"Method for Transmitting PPP Over Ethernet (PPPoE)"
|
RFC 3817
|
L2TP Active Discovery Relay for PPPoE
Network Working Group Internet-Draft, L2TP Active Discovery Relay for PPPoE, which can be seen at http://www.ietf.org/internet-drafts/draft-dasilva-l2tp-relaysvc-06.txt
|
Technical Assistance
Description
|
Link
|
The Cisco Technical Support website contains thousands of pages of searchable technical content, including links to products, technologies, solutions, technical tips, and tools. Registered Cisco.com users can log in from this page to access even more content.
|
http://www.cisco.com/techsupport
|
Feature Information for Enabling PPPoE Relay Discovery and Service Selection Functionality
Table 10 lists the features in this module and provides links to specific configuration information. Only features that were introduced or modified in Release 12.3(4)T or later releases appear in the table.
Not all commands may be available in your Cisco IOS software release. For details on when support for specific commands was introduced, see the command reference documents.
If you are looking for information on a feature in this technology that is not documented here, see the "Configuring Broadband Access Aggregation Features Roadmap."
Cisco IOS software images are specific to a Cisco IOS software release, a feature set, and a platform. Use Cisco Feature Navigator to find information about platform support and Cisco IOS software image support. Access Cisco Feature Navigator at http://www.cisco.com/go/fn. You must have an account on Cisco.com. If you do not have an account or have forgotten your username or password, click Cancel at the login dialog box and follow the instructions that appear.
Note
Table 10 lists only the Cisco IOS software release that introduced support for a given feature in a given Cisco IOS software release train. Unless noted otherwise, subsequent releases of that Cisco IOS software release train also support that feature.
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