Configuring PPP over Ethernet Session Limit Support

First Published: May 4, 2005
Last Updated: November 17, 2010

This module provides information on how to limit the number of PPP over Ethernet (PPPoE) sessions that can be created on a router or on a Gigabit Ethernet interface for configuration.

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 for Configuring PPP over Ethernet Session Limit Support" section.

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

Contents

•Information About Configuring PPP over Ethernet Session Limit Support

•How to Configure PPP over Ethernet Session Limit Support

•Configuration Examples for PPP over Ethernet Session Limit Support

•Additional References

•Feature Information for Configuring PPP over Ethernet Session Limit Support

Information About Configuring PPP over Ethernet Session Limit Support

•Benefits of Configuring PPP over Ethernet Session Limit Support

•Trap Generation

Benefits of Configuring PPP over Ethernet Session Limit Support

•The PPPoE Session Limit Support feature prevents the router from using too much memory for virtual access by limiting the number of PPPoE sessions that can be created on a router or on all Ethernet interfaces and subinterfaces as well as ATM interfaces and subinterfaces.

•The SNMP Enhancements for ASR 1000 feature enhances Cisco ASR 1000 Aggregation Series Router to count the PPPoE sessions in PTA, FWDED, and TRANS state for a particular physical interface, and the total number of sessions that exist in a physical interface. Provision for using a system-wide threshold trap and per-physical threshold trap is provided through SNMP. These functionalities enable users to retrieve the total number of sessions and per-interface session-loss threshold value.

Trap Generation

In scenarios where you must deploy ASR 1000 Series Routers with one physical port mapped to one DSLAM and if the total number of sessions for the DSLAM falls below the threshold value on a physical interface, due to a loss of high number of sessions, a notification trap is generated. You can use these traps to investigate the issue and take immediate actions.

When the number of active sessions falls below the threshold value, only one trap is generated. Further traps are not sent even if the number of sessions continue to decrease. The next set of traps are sent only if the number of sessions rise above the configured threshold value and fall. This criterion is applicable to both global and per-interface traps.

When threshold values are configured in both global and per-interface configuration modes, then both the threshold values are monitored separately. Traps are sent when the session count falls below the threshold value either in global configuration mode or in per-interface configuration mode.

How to Configure PPP over Ethernet Session Limit Support

•Specifying the Maximum Number of PPPoE Sessions on a Router (optional)

•Specifying the Maximum Number of PPPoE Sessions on a Gigabit Ethernet Interface (optional)

•Configuring System-Wide Threshold Parameters (required)

Specifying the Maximum Number of PPPoE Sessions on a Router

Perform this task to specify the maximum number of PPPoE sessions that can be created on a router.

SUMMARY STEPS

1. enable

2. configure terminal

3. bba-group pppoe {name | global}

4. virtual-template template-number

5. sessions per-mac limit per-mac-limit

6. sessions per-vlan limit per-vlan-limit [inner vlan-id]

7. sessions per-vc limit per-vc-limit [threshold threshold-value]

8. sessions max limit number-of-sessions [threshold threshold-value]

9. 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 

bba-group pppoe {name | global}

Example:

Router(config)# bba-group pppoe global

Configures a broadband aggregation (BBA) group to be used to establish PPPoE sessions and enters BBA group configuration mode.

•name—Name of the BBA group. You can have multiple BBA groups.

•global— Specifies the PPPoE profile that serves as the default profile for any PPPoE port (Gigabit Ethernet interface or VLAN) that has not been assigned a specific PPPoE profile.

Step 4 

virtual-template template-number

Example:

Router(config-bba-group)# virtual-template 1

Specifies the virtual template that will be used to clone virtual access interfaces for all PPPoE ports that use this PPPoE profile.

Step 5 

sessions per-mac limit per-mac-limit

Example:

Router(config-bba-group)# sessions per-mac limit 1000

(Optional) Configures the maximum number of PPPoE sessions allowed per MAC session limit in a PPPoE profile. The default MAC session limit is 100.

Step 6 

sessions per-vlan limit per-vlan-limit [inner vlan-id]

Example:

Router(config-bba-group)# session per-vlan limit 4000 inner 3500

(Optional) Sets the session limit for the inner VLAN on QinQ subinterface. The default session limit is 100.

Note The per-VLAN limit is only applicable to Gigabit Ethernet subinterfaces (802.1q VLANs).

Step 7 

sessions per-vc limit per-vc-limit [threshold threshold-value]

Example:

Router(config-bba-group)# sessions per-vc limit 2000

(Optional) Sets the maximum number of PPPoE sessions allowed per VC session limit in a PPPoE profile. The default session limit is 100.

Note The per-VC limit is applicable only to ATM interfaces and subinterfaces.

Step 8 

sessions max limit number-of-sessions [threshold threshold-value]

Example:

Router(config-bba-group)# sessions max limit 32000

Configures the PPPoE global profile with the maximum number of PPPoE sessions that will be permitted on a router, and sets the PPPoE session-count threshold at which a Simple Network Management Protocol (SNMP) trap will be generated.

Note This command applies only to the global profile.

Step 9 

exit

Example:

Router(config-bba-group)# exit

Returns to global configuration mode.

Specifying the Maximum Number of PPPoE Sessions on a Gigabit Ethernet Interface

Perform this task to specify the maximum number of PPPoE sessions that can be created on a Gigabit Ethernet interface.

SUMMARY STEPS

1. enable

2. configure terminal

3. interface {GigabitEthernet | tenGigabitEthernet} slot/subslot/port [.subinterface]

4. pppoe enable [group group-name]

5. pppoe max-sessions number

6. end

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 

interface {GigabitEthernet | tenGigabitEthernet} slot/subslot/port[.subinterface]

Example:

Router(config)# interface GigabitEthernet0/0/1

Specifies a Gigabit Ethernet interface and enters interface configuration mode.

Step 4 

pppoe enable [group group-name]

Example:

Router(config-if)# pppoe enable group one

Enables PPPoE sessions on a Gigabit Ethernet interface or subinterface.

Note If a PPPoE profile is not assigned to the interface through the use of the group group-name option, the interface will use the global PPPoE profile.

Step 5 

pppoe max-sessions number

Example:

Router(config-if)# pppoe max-sessions 10

Specifies the maximum number of PPPoE sessions permitted on the interface or subinterface.

Step 6 

end

Example:

Router(config-if)# end

(Optional) Exits interface configuration mode and returns to privileged EXEC mode.

Configuring System-Wide Threshold Parameters

Performthis task to configure the system-wide threshold parameters.

SUMMARY STEPS

1. enable

2. configure terminal

3. bba-group pppoe global

4. sessions threshold number

5. exit

6. interface type number

7. pppoe-sessions threshold number

8. end

9. show pppoe summary

DETAILED STEPS

 
Command or Action
Purpose

Step 1 

enable

Example:

Router> enable

Enables privileged EXEC mode.

Step 2 

configure terminal

Example:

Router> configure terminal

Enters global configuration mode.

Step 3 

bba-group pppoe global

Example:

Router(config)# bba-group pppoe global

Defines a PPPoE profile and enters BBA group configuration mode.

Step 4 

sessions threshold number

Example:

Router(config-bba-group)# sessions threshold 1000

Configures the global threshold value.

Step 5 

exit

Example:

Router(config-bba-group)# exit

Exits BBA group configuration mode and returns to privileged EXEC mode.

Step 6 

interface type number

Example:

Router(config-if)# interface GigabitEthernet 0/0

Enters interface configuration mode.

Step 7 

pppoe-sessions threshold number

Example:

Router(config-if)# pppoe-sessions threshold 1000

Configures per-session threshold value.

Step 8 

end

Example:

Router(config-if)# end

Exits interface configuration mode and returns to privileged EXEC mode

Step 9 

show pppoe summary

Example:

Router# show pppoe summary

Displays the count of PPPoE sessions in PTA, FWDED, and TRANS state for a particular physical interface.

Configuration Examples for PPP over Ethernet Session Limit Support

This section provides the following configuration examples:

•Example: Specifying the Maximum Number of PPPoE Sessions on a Router

•Example: Specifying the Maximum Number of PPPoE Sessions on a Gigabit Ethernet Interface

•Example: Configuring the System-wide Threshold Parameters

Example: Specifying the Maximum Number of PPPoE Sessions on a Router

The following example shows how to configure a limit of 1,000 PPPoE sessions for the router: 

bba-group pppoe global

  virtual-template 1

  sessions per-mac limit 1000

  sessions per-vlan limit 4000 inner 3500

  sessions per-vc limit 2000

Example: Specifying the Maximum Number of PPPoE Sessions on a Gigabit Ethernet Interface

The following example shows how to configure a limit of ten PPPoE sessions on the Gigabit Ethernet interface: 

interface GigabitEthernet 1/0/0

  pppoe enable

  pppoe max-sessions 10

The following example shows how to configure a limit of ten PPPoE sessions on the Gigabit Ethernet subinterface by using the encapsulation command: 

interface GigabitEthernet 0/0/0.1

  encapsulation dot1q 2 

  pppoe enable

  pppoe max-sessions 10

Example: Configuring the System-wide Threshold Parameters

The following example shows how to configure global and per-session threshold values: 

Router# configure terminal 

Router(config)# bba-group pppoe global 

Router(config-bba-group)# sessions threshold 1000

Router(config-bba-group)# exit

Router# configure terminal

Router(config)# interface GigabitEthernet 0/0 

Router(config-if)# pppoe-sessions threshold 90

Router(config-if)# end

The following example shows how to use the show pppoe summary command to display the count of the PPPoE sessions: 

Router# show pppoe summary


PTA  : Locally terminated sessions

FWDED: Forwarded sessions

TRANS: All other sessions (in transient state)

TOTAL PTA   FWDED TRANS

TOTAL 1       1       0       0

GigabitEthernet0/3/1 1       1       0       0

Additional References

Related Documents

Related Topic
Document Title

Cisco IOS commands

Cisco IOS Master Commands List, All Releases

Broadband and DSL commands

Cisco IOS Broadband and DSL Command Reference

Broadband access aggregation of PPPoE sessions

Providing Protocol Support for Broadband Access Aggregation of PPPoE Sessions


Standards

Standards
Title

No new or modified standards are supported by this feature, and support for existing standards has not been modified by this feature.

—


MIBs

MIBs
MIBs Link

No new or modified MIBs are supported by this feature, and support for existing MIBs has not been modified by this feature.

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

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


RFCs

RFCs
Title

No new or modified RFCs are supported by this feature, and support for existing RFCs has not been modified by this feature.

—


Technical Assistance

Description
Link

The Cisco Support and Documentation website provides online resources to download documentation, software, and tools. Use these resources to install and configure the software and to troubleshoot and resolve technical issues with Cisco products and technologies. Access to most tools on the Cisco Support and Documentation website requires a Cisco.com user ID and password.

http://www.cisco.com/cisco/web/support/index.html


Feature Information for Configuring PPP over Ethernet Session Limit Support

Table 1 lists the features in this module and provides links to specific configuration information.

Use Cisco Feature Navigator to find information about platform support and software image support. Cisco Feature Navigator enables you to determine which software images support a specific software release, feature set, or platform. To access Cisco Feature Navigator, go to http://www.cisco.com/go/cfn. An account on Cisco.com is not required.

Note Table 1 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.

Table 1 Feature Information for Providing PPP over Ethernet Session Limit Support 

Feature Name
Releases
Feature Information

PPP over Ethernet Session Limit Support

Cisco IOS XE Release 2.1 Cisco IOS XE Release 2.4

This feature was introduced on Cisco ASR 1000 Series Aggregation Services Routers.

The PPPoE Session Limit Support feature enables you to limit the number of PPPoE sessions that can be created on a router or on a Gigabit Ethernet interface for configuration.

This feature was integrated into Cisco IOS XE Release 2.4.

The following sections provide information about this feature:

•Information About Configuring PPP over Ethernet Session Limit Support

•How to Configure PPP over Ethernet Session Limit Support

SNMP Enhancements for ASR 1000

Cisco IOS XE Release 3.2S

The SNMP Enhancements for ASR 1000 feature enhances Cisco ASR 1000 Aggregation Series Routers to provide the count of the PPPOE sessions in PTA, Forwarded, and TRANS state for a particular physical interface, and the total count of sessions that exist in a physical interface.

This feature was introduced in Cisco IOS XE 3.2S.

The following sections provide information about this feature:

•Information About Configuring PPP over Ethernet Session Limit Support

•How to Configure PPP over Ethernet Session Limit Support

The following commands were introduced or modified: pppoe-sessions threshold, sessions threshold.


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