PPPoE Session Limit

Table Of Contents

PPPoE Session Limit

Contents

Feature Overview

Benefits

Related Documents

Supported Platforms

Supported Standards, MIBs, and RFCs

Configuration Tasks

Limiting the Number of PPPoE Sessions on the Router

Limiting the Number of PPPoE Sessions on a PVC

Limiting the Number of PPPoE Sessions in a VC Class

Limiting the Number of PPPoE Sessions in an ATM PVC Range

Limiting the Number of PPPoE Sessions on an Individual PVC Within a PVC Range

Verifying PPPoE Session Limits

Monitoring and Maintaining PPPoE Session Limits

Configuration Examples

Limiting the Number of PPPoE Sessions on the Router Example

Limiting the Number of PPPoE Sessions on a PVC Example

Limiting the Number of PPPoE Sessions in a VC Class Example

Limiting the Number of PPPoE Sessions in an ATM PVC Range Example

Limiting the Number of PPPoE Sessions on an Individual PVC Within a PVC Range Example

Command Reference

pppoe limit max-sessions

pppoe max-sessions

PPPoE Session Limit

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Feature History for PPPoE Session Limit

Release	Modification
12.2(1)DX	This feature was introduced.
12.2(2)DD	This feature was integrated into Cisco IOS Release 12.2(2)DD.
12.2(27)SBA	This feature was integrated into Cisco IOS Release 12.2(27)SBA.

Finding Support Information for Platforms and Cisco IOS Software Images

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Contents

•Feature Overview

•Supported Platforms

•Supported Standards, MIBs, and RFCs

•Configuration Tasks

•Monitoring and Maintaining PPPoE Session Limits

•Configuration Examples

•Command Reference

Feature Overview

The PPP over Ethernet (PPPoE) Session Limit feature enables you to limit the number of PPPoE sessions that can be created on a router or on an ATM permanent virtual connection (PVC), PVC range, virtual circuit (VC) class, or Ethernet subinterface.

Before the introduction of this feature, there was no way to limit the number of PPPoE sessions that could be created on a router. Not having a limit was potentially a problem because it was possible that the router could create so many PPPoE sessions that it would run out of memory.

To prevent the router from using too much memory for virtual access, the PPPoE Session Limit feature introduces a new command and a modification to an existing command that enable you to specify the maximum number of PPPoE sessions that can be created. The new pppoe limit max-sessions command limits the number of PPPoE sessions that can be created on the router. The modified pppoe max-sessions command limits the number of PPPoE sessions that can be created on an ATM PVC, PVC range, VC class, or Ethernet subinterface.

Benefits

The PPPoE Session Limit feature prevents the router from using too much memory for virtual access by enabling you to limit the number of PPPoE sessions that can be created on a router or on an ATM PVC, PVC range, VC class, or Ethernet subinterface.

Related Documents

•Cisco IOS Security Configuration Guide, Release 12.2

•Cisco IOS Security Command Reference, Release 12.2

•ATM PVC Range and Routed Bridge Encapsulation Subinterface Grouping, Cisco IOS Release 12.1(5)T feature module

•PPPoE on ATM, Cisco IOS Release 12.1(1)T feature module

•PPPoE on Ethernet, Cisco IOS Release 12.1(2)T feature module

Supported Platforms

•Cisco 7200 series

•Cisco 7401 ASR router

Supported Standards, MIBs, and RFCs

Standards

No new or modified standards are supported by this feature.

MIBs

No new or modified MIBs are supported by this feature.

To obtain lists of supported MIBs by platform and Cisco IOS release, and to download MIB modules, go to the Cisco MIB website on Cisco.com at the following URL:

http://www.cisco.com/public/sw-center/netmgmt/cmtk/mibs.shtml

RFCs

No new or modified RFCs are supported by this feature.

Configuration Tasks

To configure PPPoE session limits, complete one or more of the following tasks.

•Limiting the Number of PPPoE Sessions on the Router (optional)

•Limiting the Number of PPPoE Sessions on a PVC (optional)

•Limiting the Number of PPPoE Sessions in a VC Class (optional)

•Limiting the Number of PPPoE Sessions in an ATM PVC Range (optional)

•Limiting the Number of PPPoE Sessions on an Individual PVC Within a PVC Range (optional)

To verify PPPoE sessions limits, complete the following task:

•Verifying PPPoE Session Limits (optional)

Limiting the Number of PPPoE Sessions on the Router

To specify the maximum number of PPPoE sessions that can be created on a router, use the following command in VPDN group configuration mode:

Command	Purpose
Router(config-vpdn)# pppoe limit max-sessions number-of-sessions	Specifies the maximum number of PPPoE sessions that will be permitted on the router. •number-of-sessions—Maximum number of PPPoE sessions that will be permitted on the router. The range is from 0 to the maximum number of interfaces on the router.

PPPoE session limits configured using the pppoe limit max-sessions command take precedence over limits configured using the pppoe limit per-vlan and pppoe limit per-mac commands.

Limiting the Number of PPPoE Sessions on a PVC

To specify the maximum number of PPPoE sessions that can be created on a PVC, use the following command in interface-ATM-VC configuration mode:

Command	Purpose
Router(config-if-atm-vc)# pppoe max-sessions number-of-sessions	Specifies the maximum number of PPPoE sessions that will be permitted on the PVC. •number-of-sessions—Maximum number of PPPoE sessions that will be permitted on the router. The range is from 0 to the maximum number of interfaces on the router.

PPPoE session limits created on a PVC using the pppoe max-sessions command take precedence over the limits created with the pppoe limit per-vc command.

PPPoE session limits created on a PVC take precedence over limits created in a VC class or ATM PVC range.

Limiting the Number of PPPoE Sessions in a VC Class

To specify the maximum number of PPPoE sessions that can be created in a VC class, use the following command in VC-class configuration mode:

Command	Purpose
Router(config-vc-class)# pppoe max-sessions number-of-sessions	Specifies the maximum number of PPPoE sessions that will be permitted in the VC class. •number-of-sessions—Maximum number of PPPoE sessions that will be permitted on the router. The range is from 0 to the maximum number of interfaces on the router.

PPPoE session limits created in a VC class using the pppoe max-sessions command take precedence over the limits created with the pppoe limit per-vc command.

PPPoE session limits created on a PVC and ATM PVC range take precedence over limits created in a VC class.

Limiting the Number of PPPoE Sessions in an ATM PVC Range

To specify the maximum number of PPPoE sessions that can be created in an ATM PVC range, use the following command in ATM PVC range configuration mode:

Command	Purpose
Router(config-if-atm-range)# pppoe max-sessions number-of-sessions	Specifies the maximum number of PPPoE sessions that will be permitted in the range. •number-of-sessions—Maximum number of PPPoE sessions that will be permitted on the router. The range is from 0 to the maximum number of interfaces on the router.

PPPoE session limits created in an ATM PVC range using the pppoe max-sessions command take precedence over the limits created with the pppoe limit per-vc command.

PPPoE session limits created in an ATM PVC range take precedence over limits created in a VC class.

Limiting the Number of PPPoE Sessions on an Individual PVC Within a PVC Range

To specify the maximum number of PPPoE sessions that can be created on an individual PVC within a PVC range, use the following command in ATM PVC-in-range configuration mode:

Command	Purpose
Router(cfg-if-atm-range-pvc)# pppoe max-sessions number-of-sessions	Specifies the maximum number of PPPoE sessions that will be permitted on the PVC. •number-of-sessions—Maximum number of PPPoE sessions that will be permitted on the router. The range is from 0 to the maximum number of interfaces on the router.

PPPoE session limits created on an individual PVC within a range using the pppoe max-sessions command take precedence over the limits created with the pppoe limit per-vc command.

PPPoE session limits created on an individual PVC within a range take precedence over limits created in a VC class or ATM PVC range.

Verifying PPPoE Session Limits

To verify that PPPoE session limits are configured correctly, use the following command in privileged EXEC mode:

Command	Purpose
Router# more system:running-config	Displays the running configuration.

Monitoring and Maintaining PPPoE Session Limits

To monitor PPPoE session limits, use the following command in EXEC mode:

Command	Purpose
Router# debug vpdn pppoe-errors	Displays PPPoE protocol errors that prevent a session from being established or errors that cause an established session to be closed.

Configuration Examples

This section provides the following configuration examples:

•Limiting the Number of PPPoE Sessions on the Router Example

•Limiting the Number of PPPoE Sessions on a PVC Example

•Limiting the Number of PPPoE Sessions in a VC Class Example

•Limiting the Number of PPPoE Sessions in an ATM PVC Range Example

•Limiting the Number of PPPoE Sessions on an Individual PVC Within a PVC Range Example

Limiting the Number of PPPoE Sessions on the Router Example

The following example shows a limit of 100 PPPoE sessions configured for the router.

Router(config)# vpdn enable

Router(config-vpdn)# vpdn-group 1

Router(config-vpdn)# accept dialin

Router(config-vpdn-acc-in)# protocol pppoe

Router(config-vpdn-acc-in)# virtual-template 1

Router(config-vpdn-acc-in)# exit

Router(config-vpdn)# pppoe limit max-sessions 100

Limiting the Number of PPPoE Sessions on a PVC Example

The following example shows a limit of 10 PPPoE sessions configured for the PVC.

Router(config)# interface ATM1/0.102 multipoint

Router(config-if)# pvc 3/304

Router(config-if-atm-vc)# encapsulation aal5snap

Router(config-if-atm-vc)# protocol pppoe

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

Limiting the Number of PPPoE Sessions in a VC Class Example

The following example shows a limit of 20 PPPoE sessions configured for the VC class called "main."

Router(config)# vc-class atm main

Router(config-vc-class)# pppoe max-sessions 20

Limiting the Number of PPPoE Sessions in an ATM PVC Range Example

The following example shows a limit of 30 PPPoE sessions configured for the ATM PVC range called "range-1."

Router(config)# interface atm 6/0.110 multipoint

Router(config-subif)# range range-1 pvc 100 4/199

Router(config-if-atm-range)# encapsulation aal5snap

Router(config-if-atm-range)# protocol ppp virtual-template 2

Router(config-if-atm-range)# pppoe max-sessions 30

Limiting the Number of PPPoE Sessions on an Individual PVC Within a PVC Range Example

The following example shows a limit of 10 PPPoE sessions configured for "pvc1," which is part of the ATM PVC range called "range1."

Router(config)# interface atm 6/0.110 multipoint

Router(config-subif)# range range1 pvc 100 4/199

Router(cfg-if-atm-range-pvc)# pvc-in-range pvc1 3/104

Router(cfg-if-atm-range-pvc)# pppoe max-sessions 10

Command Reference

This section documents modified commands only.

•pppoe limit max-sessions

•pppoe max-sessions

pppoe limit max-sessions

To specify the maximum number of PPP over Ethernet (PPPoE) sessions that will be permitted on a router, use the pppoe limit max-sessions command in VPDN group configuration mode. To remove this specification, use the no form of this command.

pppoe limit max-sessions number-of-sessions

no pppoe limit max-sessions

Syntax Description

number-of-sessions

Maximum number of PPPoE sessions that will be permitted on the router. The range is from 0 to the maximum number of interfaces on the router.

Defaults

Maximum number-of-sessions is not set.

Command Modes

VPDN group configuration

Command History

Release	Modification
12.2(1)DX	This command was introduced.
12.2(2)DD	This command was integrated into Cisco IOS Release 12.2(2)DD.
12.2(4)B	This command was integrated into Cisco IOS Release 12.2(4)B.
12.2(13)T	This command was integrated into Cisco IOS Release 12.2(13)T.
12.2(27)SB	This command was integrated into Cisco IOS Release 12.2(27)SB.

Usage Guidelines

PPPoE session limits configured using the pppoe limit per-vc, pppoe limit per-vlan, pppoe max-sessions, pppoe max-sessions (VC), and pppoe max-sessions (subinterface) commands take precedence over limits configured for the router using the pppoe limit max-sessions command.

Examples

The following example shows a limit of 100 PPPoE sessions configured for the router.

vpdn enable

vpdn-group 1

 accept dialin

  protocol pppoe

  virtual-template 1

 pppoe limit max-sessions 100

Related Commands

Command	Description
debug vpdn pppoe-errors	Displays PPPoE protocol errors that prevent a session from being established or errors that cause an established session to be closed.
pppoe limit per-mac	Specifies the maximum number of PPPoE sessions to be sourced from a MAC address.
pppoe limit per-vc	Specifies the maximum number of PPPoE sessions permitted on all VCs.
pppoe limit per-vlan	Specifies the maximum number of PPPoE sessions permitted on a VLAN.
pppoe max-sessions	Specifies the maximum number of PPPoE sessions permitted on an ATM PVC, PVC range, VC class, or Ethernet subinterface.

pppoe max-sessions

To specify the maximum number of PPP over Ethernet (PPPoE) sessions that will be permitted on an ATM permanent virtual circuit (PVC), PVC range, virtual circuit (VC) class, or Ethernet subinterface, use the pppoe max-sessions command in the appropriate mode. To remove this specification, use the no form of this command.

pppoe max-sessions number-of-sessions

no pppoe max-sessions

Syntax Description

number-of-sessions

Maximum number of PPPoE sessions that will be permitted. Note The PPPoE session limit in the case of a PVC range applies to each PVC in the range. This limit is not cumulative on all PVCs belonging to the range.

Defaults

Maximum number of sessions is not set.

Command Modes

Ethernet subinterface configuration
Interface-ATM-VC configuration
VC-class configuration
ATM PVC range configuration
PVC-in-range configuration

Command History

Release	Modification
12.1(5)T	This command was introduced.
12.2(4)T	This command was modified to limit PPPoE sessions on ATM PVCs, PVC ranges, and VC classes.
12.2(27)SB	This command was integrated into Cisco IOS Release 12.2(27)SB.

Usage Guidelines

PPPoE sessions can be limited in the following ways:

•The pppoe limit max-sessions command limits the total number of PPPoE sessions on the router, regardless of the type of medium the sessions are using.

•The pppoe limit per-mac command limits the number of PPPoE sessions that can be sourced from a single MAC address. This limit also applies to all PPPoE sessions on the router.

•The pppoe limit per-vc and pppoe limit per-vlan commands limit the number of PPPoE sessions on all PVCs or VLANs on the router. The pppoe max-sessions command limits the number of PPPoE sessions on a specific PVC or VLAN. Limits created for a specific PVC or VLAN using the pppoe max-session command take precedence over the global limits created with the pppoe limit per-vc and pppoe limit per-vlan commands.

PPPoE session limits created on an ATM PVC take precedence over limits created in a VC class or ATM PVC range.

PPPoE session limits created in an ATM PVC range take precedence over limits created in a VC class.

Examples

Ethernet Subinterface Example

The following example shows a limit of 200 PPPoE sessions configured for the subinterface:

interface FastEthernet 0/0.10

 encapsulation dot1Q 10

 pppoe enable

 pppoe max-sessions 200

ATM PVC Example

The following example shows a limit of 10 PPPoE sessions configured for the PVC:

interface ATM1/0.102 multipoint

 pvc 3/304

  encapsulation aal5snap

  protocol pppoe

  pppoe max-sessions 10

VC Class Example

The following example shows a limit of 20 PPPoE sessions that will be permitted per PVC in the VC class called "main":

vc-class atm main

 pppoe max-sessions 20

ATM PVC Range Example

The following example shows a limit of 30 PPPoE sessions that will be permitted per PVC in the PVC range called "range-1":

interface atm 6/0.110 multipoint

 range range-1 pvc 100 4/199

  encapsulation aal5snap

  protocol ppp virtual-template 2

  pppoe max-sessions 30

Individual PVC Within a PVC Range Example

The following example shows a limit of 10 PPPoE sessions configured for "pvc1", which is part of the ATM PVC range called "range1":

interface atm 6/0.110 multipoint

 range range1 pvc 100 4/199

  pvc-in-range pvc1 3/104

   pppoe max-sessions 10

Related Commands

Command	Description
debug vpdn pppoe-errors	Displays PPPoE protocol errors that prevent a session from being established or errors that cause an established session to be closed.
pppoe limit max-sessions	Specifies the maximum number of PPPoE sessions that will be permitted on a router.
pppoe limit per-mac	Specifies the maximum number of PPPoE sessions to be sourced from a MAC address.
pppoe limit per-vc	Specifies the maximum number of PPPoE sessions permitted on all VCs.
pppoe limit per-vlan	Specifies the maximum number of PPPoE sessions permitted on a VLAN.

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