Identification of Subscribers Using the PPPoE Remote Circuit Identifier

You can enable the router to capture and format a vendor-specific tag containing a PPPoE remote circuit ID transmitted from a digital subscriber line access multiplexer (DSLAM) device. The router can then send this value to a Remote Authentication Dial-In User Service (RADIUS) server or to a Layer 2 Tunneling Protocol (L2TP) network server (LNS) to uniquely identify subscriber locations.

This feature is supported on all modules on which you can configure PPPoE interfaces. The feature is particularly useful in Ethernet-based Broadband Remote Access Server (B-RAS) configurations as a means of uniquely identifying subscribers connected to the router on a single Ethernet link.

For detailed configuration instructions, see Configuring PPPoE Remote Circuit ID Capture.

Application

When a connection between an E Series router and a DSLAM is on an ATM interface, subscribers are typically assigned an ATM PVC to communicate with the router. Each ATM PVC is created on a different ATM 1483 subinterface. When a RADIUS server in this configuration sends messages to the router containing the NAS-Port-Id [87] RADIUS attribute, each ATM 1483 subinterface produces a unique NAS-Port-Id that can differentiate subscribers on the ATM link.

By contrast, when the connection between the router and the DSLAM is on an Ethernet interface that does not use either virtual LANs (VLANs) or stacked VLANs (S-VLANs), the NAS-Port-Id value is the same for all subscribers on the Ethernet link. Enabling the router to capture the remote circuit ID sent from the DSLAM and use it as a RADIUS or L2TP attribute facilitates the process of identifying individual subscribers on an Ethernet link.

PPPoE Remote Circuit ID Capture

When you enable capture of the PPPoE remote circuit ID by issuing the pppoe remote-circuit-id command, the E Series router captures the remote circuit ID value if it is sent from the DSLAM. The PPPoE intermediate agent on the DSLAM appends a vendor-specific tag containing the remote circuit ID to the existing PPPoE PADI or PADR packet and sends this packet to the E Series router. The PPPoE remote circuit ID value can be a maximum of 64 characters. The router stores this value on the line module on which the PPPoE interface is configured.

PPPoE Remote Circuit ID Format

By default, the router formats the captured PPPoE remote circuit ID to include only the agent-circuit-id suboption (suboption 1) of the PPPoE intermediate agent tags sent from the DSLAM. To configure a nondefault format for the captured PPPoE remote circuit ID, you can use one of the radius remote-circuit-id-format commands listed in Table 34.

Table 34: Configuring Nondefault Formats for the PPPoE Remote Circuit ID

To Configure This Nondefault Format

Use This Command

Include only the agent-remote-id suboption (suboption 2) of the tags supplied by the PPPoE intermediate agent

host1(config)#radius remote-circuit-id-format agent-remote-id

Include both the agent-circuit-id suboption (suboption 1) and the agent-remote-id suboption (suboption 2) of the tags supplied by the PPPoE intermediate agent

host1(config)#radius remote-circuit-id-format agent-circuit-id agent-remote-id

Include the NAS-Identifier [32] RADIUS attribute with either or both of the agent-circuit-id and agent-remote-id suboptions of the tags supplied by the PPPoE intermediate agent

host1(config)#radius remote-circuit-id-format nas-identifier agent-circuit-id

or

host1(config)#radius remote-circuit-id-format nas-identifier agent-remote-id

or

host1(config)#radius remote-circuit-id-format nas-identifier agent-circuit-id agent-remote-id

Append the agent-circuit-id suboption to an interface specifier that is consistent with the recommended format in the DSL Forum Technical Report (TR)-101—Migration to Ethernet-Based DSL Aggregation (April 2006).

For details about how the router implements this format, see Format for dsl-forum-1 Keyword.

host1(config)#radius remote-circuit-id-format dsl-forum-1

For more information about configuring the format of the PPPoE remote circuit ID value, see radius remote-circuit-id-format.

Remote Circuit ID Delimiter

If the format of the PPPoE remote circuit ID consists of two or more components, the router uses a # character by default to delimit the components. Optionally, you can use the radius remote-circuit-id-delimiter command to configure a nondefault delimiter character (for example, ! or %) to separate multiple components in the PPPoE remote circuit ID value. For information about how to use this command, see radius remote-circuit-id-delimiter.

Format for dsl-forum-1 Keyword

When you specify the radius remote-circuit-id-format command with the dsl-forum-1 keyword, the router appends the agent-circuit-id suboption value to an interface specifier that is consistent with the recommended format in the DSL Forum Technical Report (TR)-101—Migration to Ethernet-Based DSL Aggregation (April 2006).

The format of the PPPoE remote circuit ID when you use the dsl-forum-1 keyword is as follows:

dslForum1InterfaceSpecifier#agent-circuit-id

where:

If the DSLAM transmits empty data for agent-circuit-id, the router appends the value 0/0/0/0/0/0 to dslForum1InterfaceSpecifier.

To obtain the value for dslForum1InterfaceSpecifier, the router translates an internally generated interface specifier into the format for the dsl-forum-1 keyword, using the following conventions:

Format Examples for dsl-forum-1 Keyword

Table 35 provides several examples of how the router uses the conventions described in Format for dsl-forum-1 Keyword to translate internally generated interface specifiers into the format of the dslForum1InterfaceSpecifier value. The examples in the table use adapter 1 for interfaces on an E120 or E320 router, and adapter 0 (no adapter value) for interfaces on ERX14xx models, ERX7xx models, and the ERX310 router.

Table 35: Interface Specifier Format Examples for dsl-forum-1 Keyword

Interface Example

Internal Router Format

How Router Translates

Format of dslForum1InterfaceSpecifier

ATM 1483 subinterface on slot 2, port 0, subinterface 1 with VPI 100 and VCI 101

atm 2/0.1:100.101

  • Sets adapter to 0
  • Ignores subinterface 1
  • Uses other values as supplied

atm 2/0/0:100.101

ATM 1483 subinterface on slot 3, adapter 1, port 7, subinterface 6 with VPI 200 and VCI 201

atm 3/1/7.6:200.201

  • Ignores subinterface 6
  • Uses other values as supplied

atm 3/1/7:200.201

Gigabit Ethernet interface on slot 2, port 0 with no VLAN or S-VLAN subinterfaces

gigabitEthernet 2/0

  • Sets adapter to 0
  • Sets both svlanId and vlanId to 4096
  • Uses other values as supplied

eth 2/0/0:4096.4096

Gigabit Ethernet interface on slot 4, adapter 1, port 1 with no VLAN or S-VLAN subinterfaces

gigabitEthernet 4/1/1

  • Sets both svlanId and vlanId to 4096
  • Uses other values as supplied

eth 4/1/1:4096.4096

Gigabit Ethernet interface on slot 2, port 0, subinterface 1 with VLAN ID 5

gigabitEthernet 2/0.1:5

  • Sets adapter to 0
  • Ignores subinterface 1
  • Sets svlanId to 4096
  • Uses other values as supplied

eth 2/0/0:4096.5

Gigabit Ethernet interface on slot 4, adapter 1, port 1, subinterface 3 with VLAN ID 10

gigabitEthernet 4/1/1.3:10

  • Ignores subinterface 3
  • Sets svlanId to 4096
  • Uses other values as supplied

eth 4/1/1:4096.10

Gigabit Ethernet interface on slot 2, port 0, subinterface 1 with S-VLAN ID 5 and VLAN ID 6

gigabitEthernet 2/0.1:5-6

  • Sets adapter to 0
  • Ignores subinterface 1
  • Replaces - (hyphen) between svlanId and vlanID with . (period)
  • Uses other values as supplied

eth 2/0/0:5.6

Gigabit Ethernet interface on slot 4, adapter 1, port 1, subinterface 3 with S-VLAN ID 10 and VLAN ID 20

gigabitEthernet 4/1/1.3:10-20

  • Ignores subinterface 3
  • Replaces - (hyphen) between svlanId and vlanID with . (period)
  • Uses other values as supplied

eth 4/1/1:10.20

Use by RADIUS or L2TP

Enabling the router to capture and format the PPPoE remote circuit ID sent from the DSLAM has no effect by itself. To use the PPPoE remote circuit ID value, you must send it to a RADIUS server, to an L2TP network server (LNS), or to both by doing one or more of the following:

For more information about configuring RADIUS and L2TP on E Series routers, see the JunosE Broadband Access Configuration Guide.

System Event Log

You can use the radiusSendAttributes system event log category to troubleshoot applications that use PPPoE remote circuit ID capture. The radiusSendAttributes event category logs RADIUS attributes added to outbound RADIUS requests.

You can also use the log severity debug pppoeControlPacket command to configure a packet trace log for a PPPoE interface that includes the PPPoE remote circuit ID value captured on that interface. For information about how to use the log severity debug pppoeControlPacket command, see Troubleshooting PPPoE Interfaces.

For information about how to log system events, see Overview of System Logging.

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