Feature Overview

The Point-to-Point Protocol over Ethernet (PPPoE) feature allows a PPP session to be initiated on a simple bridging Ethernet connected client. The session is transported over the ATM link via encapsulated Ethernet-bridged frames. The session can be terminated at either a local exchange carrier central office or an internet service provider (ISP) point of presence. The termination device is a Cisco 6400 Universal Access Concentrator.

For information on configuring PPP over Ethernet, refer to the "Configuration Tasks" section later in this document.

Figure 1: Typical PPP over Ethernet Topology

Benefits

Uses Existing Customer Premise Equipment

PPPoE can be used on existing customer premise equipment, extending the PPP session over the bridged Ethernet LAN to the PC.

Preserves Point-to-Point

PPPoE preserves the point-to-point session used by ISPs in the current dial-up model. PPPoE is the only protocol capable of running point-to-point over Ethernet without requiring an intermediate IP stack.

Restrictions

The following restrictions apply to this feature for Cisco IOS Release 12.0(3)DC:

PPPoE is supported on ATM permanent virtual circuits (PVCs) only.
The Cisco 6400 can not initiate dial-out PPPoE sessions.
PPPoE supports Cisco Express Forwarding (CEF) only. Fastswitching on PPPoE virtual-access interfaces is not supported.

Supported Platforms

PPP over Ethernet is supported on the Cisco 6400.

Prerequisites

The Cisco 6400 node route processor (NRP) requires 128MB of DRAM to support up to 2800 concurrent PPPoE sessions. An NRP with 64MB DRAM can support up to 2000 concurrent PPPoE sessions.

Supported Standards, MIBs, and RFC

MIBs

None.

RFCs

Informational RFC 2516, A Method for Transmitting PPP Over Ethernet (PPPoE), February 1999

Standards

None.

Configuration Tasks

Perform the following tasks to configure PPP over Ethernet on ATM:

Configuring a Virtual Template for PPPoE

To configure PPPoE on a virtual-access interface, use the following commands starting in global configuration mode.

Step Command Purpose

1 .

Router(config)#vpdn enable

Enable virtual private dial-up networking.

2 .

Router(config)#vpdn-group number

Select VPDN-group configuration mode.

3 .

Router(config-vpdn)#accept dialin pppoe virtual-template 
number

Configure the router to accept dial-in PPPoE calls.

4 .

Router(config-vpdn)#pppoe limit per-mac number

(optional) Limit the number of PPPoE sessions that originate from one MAC address. Default is 100.

5 .

Router(config-vpdn)#pppoe limit per-vc number

(optional) Limit the number of PPPoE sessions that can be established on a virtual circuit. Default is 100.

6 .

Router(config-vpdn)#exit

Return to global configuration mode.

7 .

Router(config)#virtual-template template-number 
pre-clone number

(optional) Create "pre-cloned" virtual-access interfaces equal to the expected maximum number of concurrent PPPoE sessions.¹

¹Instead of creating virtual-access interfaces on demand, a number of pre-cloned virtual-access interfaces may be created and saved to a private PPPoE list. This cloning procedure reduces the CPU workload while PPPoE sessions are established.

Configuring PPPoE on an ATM Interface

To configure PPPoE on an ATM interface, use the following commands starting in global configuration mode.

Step Command Purpose

1 .

Router(config)#interface atm slot/0.subinterface-number 
multipoint

Specify an ATM multipoint subinterface.

2 .

Router(config-if)#pvc [name] VPI/VCI

Configure the PVC.

3 .

Router(config-if)#encapsulation aal5snap

Configure SNAP encapsulation.

4 .

Router(config-if)#protocol pppoe

Select PPPoE as the protocol for the PVC.

5 .

Router(config)#exit

Return to global configuration mode.

Setting the IP MTU

To allow PPPoE to operate over the virtual-access interface, the IP maximum transmission unit (MTU) must be set to 1492. Use the following commands, starting in global configuration mode, to set the IP MTU.

Step Command Purpose

1 .

Router(config)#interface virtual-template number

Select the virtual-access interface to be configured.

2 .

Router(config-if)#ip mtu 1492

Set the IP MTU to 1492.

3 .

Router(config)#exit

Return to global configuration mode.

Verifying PPPoE

Step 1 Enter the show vpdn command from interface configuration mode. This output shows PPPoE session information. Confirm that the virtual-access interface status (VASt) is UP.

Router#show vpdn
 
PPPOE Tunnel and Session
 
Session count: 1
 
PPPoE Session Information
SID	        RemMAC	          LocMAC	       Intf    	VASt    	OIntf	   VC
1	       0010.54db.bc38  	0050.7327.5dc3  	Vi1	     UP      	AT0/0/0	 0/40


SID	Session ID for the PPPoE session.
RemMAC	MAC address of the host.
LocMAC	MAC address of the ATM interface.
Intf	Virtual-access interface associated with the PPP session.
VASt	State of the virtual-access interface.
OIntf	Outgoing interface.
VC	Virtual circuit on which PPP session flows.

The session information fields from the show vpdn display are detailed below:

Step 2 Enter the show atm pvc command from interface configuration mode. The last line of the output, "PPPOE enabled", confirms that PPPoE is enabled on this VC.

Router#show atm pvc 40
ATM0/0/0.2: VCD: 1, VPI: 0, VCI: 40
UBR, PeakRate: 155000
AAL5-LLC/SNAP, etype:0x0, Flags: 0xC20, VCmode: 0x0
OAM frequency: 0 second(s), OAM retry frequency: 1 second(s), OAM retry
frequency: 1 second(s)
OAM up retry count: 3, OAM down retry count: 5
OAM Loopback status: OAM Disabled
OAM VC state: Not Managed
ILMI VC state: Not Managed
InARP frequency: 15 minutes(s)
InPkts: 100, OutPkts: 51, InBytes: 4692, OutBytes: 2294
InPRoc: 48, OutPRoc: 51, Broadcasts: 0
InFast: 0, OutFast: 0, InAS: 52, OutAS: 0
OAM cells received: 0
F5 InEndloop: 0, F5 InSegloop: 0, F5 InAIS: 0, F5 InRDI: 0
F4 InEndloop: 0, F4 InSegloop: 0, F4 InAIS: 0, F4 InRDI: 0
OAM cells sent: 0
F5 OutEndloop: 0, F5 OutSegloop: 0, F5 OutRDI: 0
F4 OutEndloop: 0, F4 OutSegloop: 0, F4 OutRDI: 0
OAM cell drops: 0
Status: UP
PPPOE enabled.

Troubleshooting Tips

Concurrent Bridging and PPPoE

PPPoE can operate concurrently with bridging on an ATM interface. This allows PPPoE to operate on one or more specific traffic protocols, leaving other protocols to be bridged.

VC Classes

You can also configure PPP over Ethernet in a VC class and apply this VC class to an ATM VC, subinterface, or interface. For information about configuring a VC class, refer to the section "Configure VC Classes" in the chapter "Configuring ATM" of the Wide-Area Networking Configuration Guide for Cisco IOS Release 12.0.

Cisco Express Forwarding

In order to gain maximum packet switching performance, Cisco Express Forwarding (CEF) should be enabled on the virtual-access interface. For information about enabling Cisco Express Forwarding, refer to the section "Configuring Cisco Express Forwarding" in the chapter "Cisco Express Forwarding" of the Cisco IOS Switching Services Configuration Guide for IOS Release 12.0.

Monitoring and Maintaining PPP over Ethernet


Command	Purpose
`show atm pvc`	Display ATM PVC and traffic information, including PPPoE status.
`show vpdn`	Display PPPoE session information, including MAC addresses and virtual-access interfaces.
`show vpdn session packet`	Display PPPoE session statistics.
`show vpdn session all`	Display PPPoE session information for each session ID.
`show vpdn tunnel`	Display PPPoE session count for the tunnel.

Configuration Examples

This section provides the following configuration examples:

PPPoE Configuration on a PVC

In the following example, PPPoE is enabled directly on a PVC:

Router(config)#vpdn enable
Router(config)#vpdn-group 1
Router(config-vpdn)#accept dialin pppoe virtual-template 1
Router(config-vpdn)#exit
Router(config)#virtual-template 1 pre-clone 500
 
Router(config)#interface atm 2/0.1 multipoint
Router(config-if)#pvc 0/60
Router(config-if-atm-vc)#encapsulation aal5snap
Router(config-if-atm-vc)#protocol pppoe
Router(config-if-atm-vc)#exit
Router(config-if)#exit
 
Router(config)#ip cef
Router(config)#interface virtual-template 1
Router(config-if)#ip address 10.0.1.2 255.255.255.0
Router(config-if)#ip mtu 1492
Router(config-if)#ip route-cache cef
Router(config-if)#exit

PPPoE Configuration Using VC Class

In the following example, PPPoE is configured on a VC class called users. This VC class is then applied to a particular PVC:

Router(config)#vpdn enable
Router(config)#vpdn-group 1
Router(config-vpdn)#accept dialin pppoe virtual-template 1
Router(config-vpdn)#exit
Router(config)#virtual-template 1 pre-clone 500
 
Router(config)#interface atm 2/0.1 multipoint
Router(config-if)#pvc 0/60
Router(config-if-atm-vc)#class users
Router(config-if-atm-vc)#exit
Router(config-if)#exit
 
Router(config)#vc-class atm users
Router(config-vc-class)#encapsulation aal5snap
Router(config-vc-class)#protocol pppoe
Router(config-vc-class)#exit
 
Router(config)#ip cef
Router(config)#interface virtual-template 1
Router(config-if)#ip address 10.0.1.2 255.255.255.0
Router(config-if)#ip mtu 1492
Router(config-if)#ip route-cache cef
Router(config-if)#exit

Concurrent PPPoE and Bridging

In the following example, both PPPoE and bridging are configured to operate concurrently on the same DSL link:

Router(config)#vpdn enable
Router(config)#vpdn-group 1
Router(config)#accept dialin pppoe virtual-template 1
Router(config-vpdn)#exit
Router(config)#virtual-template 1 pre-clone 500
Router(config)#bridge 1 protocol ieee
Router(config)#bridge 1 route ip
 
Router(config)#interface atm 2/0.1 multipoint
Router(config-if)#bridge-group 1
Router(config-if)#pvc 0/60
Router(config-if-atm-vc)#encapsulation aal5snap
Router(config-if-atm-vc)#protocol pppoe
Router(config-if-atm-vc)#exit
Router(config-if)#exit
 
Router(config)#ip cef
Router(config)#interface virtual-template 1
Router(config-if)#ip address 10.0.1.2 255.255.255.0
Router(config-if)#ip mtu 1492
Router(config-if)#ip route-cache cef
Router(config-if)#exit

Command Reference

This section documents modified commands. All other commands used with this feature are documented in the Cisco IOS Release 12.0 command references.

accept dialin

To specify the virtual template to use for cloning new virtual-access interfaces when an incoming tunnel connection is requested from a specific peer, use the accept dialin VPDN group command. To disable authentication and virtual template cloning, use the no form of this command.

accept dialin [l2f | l2tp | any | pppoe] virtual-template number [remote remote-peer-name]

no accept dialin [l2f | l2tp | any | pppoe] virtual-template number [remote remote-peer-name]

Syntax Description


l2f \| l2tp \| any \| pppoe	(Optional) Indicates which protocol to use for a dial-in tunnel. · l2f---Layer 2 Forwarding protocol. · l2tp---Layer 2 Tunnel Protocol. · any---VPDN will use autodetect to select either L2F or L2TP. Does not apply to PPPoE. · pppoe---Point-to-Point Protocol over Ethernet.
virtual-template number	The virtual template interface from which the new virtual-access interface is cloned.
remote remote-peer-name	(Optional) Case-sensitive name that the remote peer will use for identification and tunnel authentication. Does not apply to PPPoE.

Defaults

Disabled

Command Modes

VPDN group mode

Command History


Release	Modification
12.0(1)T	This command was first introduced.
12.0(3)DC	The pppoe keyword was added.

Usage Guidelines

This command replaces the vpdn incoming command used in Cisco IOS Release 11.3. The user interface will automatically be upgraded when you reload the router with a 12.0 T image.

When used with L2F or L2TP, the router replies to a dial-in layer 2 tunnel open request from the specified peer. When the access server accepts the request, it uses the specified virtual template to clone new virtual-access interfaces.

When used with PPPoE, the accept dialin command enables the router to accept incoming PPPoE discovery packets from clients and establish PPPoE sessions with them. After the PPPoE discovery stage completes, PPPoE uses the specified virtual template to clone new virtual-access interfaces. If a pre-cloned virtual-access interface is available in PPPoE private list, PPPoE would use that virtual-access interface to establish a PPP session with the client.

Note The vpdn-group command must be configured with the accept dialin or request dialin command to be functional.

Examples

The following example allows the access server to accept a PPPoE dial-in tunnel. A virtual-access interface will be cloned from virtual-template 1:

accept dialin pppoe virtual-template 1

If you use the accept dialin command with the pppoe and virtual-template keywords and omit the remote-peer-name argument, you automatically enable a default PPPoE VPDN group, which allows all tunnels to share the same tunnel attributes:

vpdn-group 1
! Default PPPoE VPDN group
 accept dialin pppoe virtual-template 1

Related Commands


Command	Description
vpdn incoming	Specifies the local name to use for authenticating, and the virtual template to use for building interfaces for incoming connections.

pppoe limit per-mac

To limit the number of PPPoE sessions that can originate from a single MAC address, use the pppoe limit per-mac command.

pppoe limit per-mac number

Syntax Description


number	The maximum number of PPPoE sessions for a single MAC address.

Defaults

100

Command Modes

Global configuration

Command History


Release	Modification
12.0(3)DC	This command was first introduced.

Examples

The following example places a limit of 5 PPPoE sessions per MAC address:

pppoe limit per-mac 5

Related Commands


Command	Description
pppoe limit per-vc	Limits the number of PPPoE sessions that can be established on a VC.

pppoe limit per-vc

To limit the number of PPPoE sessions that can be established on a VC, use the pppoe limit per-vc command.

pppoe limit per-vc number

Syntax Description


number	The maximum number of PPPoE sessions for a VC.

Defaults

100

Command Modes

Global configuration

Command History


Release	Modification
12.0(3)DC	This command was first introduced.

Examples

The following example places a limit of 50 PPPoE sessions per VC:

pppoe limit per-vc 50

Related Commands


Command	Description
pppoe limit per-mac	Limits the number of PPPoE sessions that can be established on a single MAC address.

protocol

Use the protocol command in the appropriate command mode to do one or more of the following:

Configure a static map for an ATM PVC, SVC, or VC class.
Enable Inverse ARP or Inverse ARP broadcasts on an ATM PVC by either configuring Inverse ARP directly on the PVC or in a VC class (applies to IP and IPX protocols only).
Configure PPP over Ethernet for an ATM PVC or VC class.
Override the virtual-template configuration inherited from VC classes for all PPP over Ethernet encapsulations.

Use the no form of this command to remove a static map, disable Inverse ARP, or remove PPP over Ethernet encapsulation.

protocol protocol [protocol-address | inarp] [[no] broadcast] [virtual-template number]

no protocol protocol [protocol-address | inarp] [[no] broadcast] [virtual-template number]

Syntax Description


protocol	Choose one of the following keywords: aarp---AppleTalk ARP apollo---Apollo domain appletalk---AppleTalk arp---IP ARP bridge---bridging bstun---block serial tunnel cdp---Cisco Discovery Protocol clns---ISO CLNS clns_es---ISO CLNS end system clns_is---ISO CLNS intermediate system cmns---ISO CMNS compressedtcp---Compressed TCP decnet---DECnet decnet_node---DECnet node decnet_prime_router---DECnet prime router decnet_router-l1---DECnet router L1 decnet_router-l2---DECnet router L2 dlsw---data link switching ip---IP ipx---Novell IPX llc2---llc2 pad---PAD links ppp---PPP over ATM LLC encapsulation pppoe---PPP over Ethernet encapsulation qllc---Qualified Logical Link Control protocol rsrb---remote source-route bridging snapshot---snapshot routing support stun---serial tunnel vines---Banyan VINES xns---Xerox Network Systems protocol
protocol-address	Destination address that is being mapped to a PVC.
inarp	(Only valid for IP and IPX protocols on PVCs) Use this keyword to enable Inverse ARP on an ATM PVC. If you specify a protocol-address instead of inarp, Inverse ARP is automatically disabled for that protocol.
[no] broadcast	(Optional) Broadcast indicates that this map entry is used when the corresponding protocol sends broadcast packets to the interface-. For example, IGRP updates. Pseudobroadcasting is supported. The broadcast keyword of the protocol command takes precedence if you previously configured the broadcast command on the ATM PVC or SVC.
virtual-template number	(Optional) Use these keywords and argument only when you specify pppoe encapsulation for the protocol argument. Specifies which virtual template number to use.

Default

Inverse ARP is enabled for IP and IPX if the protocol is running on the interface and no static map is configured.

Command Modes

Interface-ATM-VC configuration (for an ATM PVC or SVC)

VC-class configuration (for a VC class)

Command History


Release	Modification
11.3(3)T	This command was first introduced.
12.0(3)DC	The pppoe keyword was added.

Usage Guidelines

If the protocol command is not explicitly configured on an ATM PVC or SVC, the VC inherits the following default configuration (listed in order of next highest precedence):

Configuration of the protocol command in a VC class assigned to the PVC or SVC itself.
Configuration of the protocol command in a VC class assigned to the PVCs or SVCs ATM subinterface.
Configuration of the protocol command in a VC class assigned to the PVCs or SVCs ATM main interface.
Global default: Inverse ARP is enabled for IP and IPX if the protocol is running on the interface and no static map is configured.

Although you can assign an explicit network layer address to a virtual-template interface, Cisco recommends that you consider two other procedures. One procedure is to use AAA to assign an address to the virtual-access interface created from the virtual template, instead of configuring any network-layer address on the virtual template. The other procedure is to use an unnumbered IP address on the virtual template.

It is currently not possible to disable a virtual-access on an individual basis. To achieve a similar effect, either delete the relevant RADIUS user entries or deconfigure the VC associated with the virtual-access.

Examples

The following example creates a static map on a VC, indicates that 192.68.34.237 is connected to this VC, and sends ATM pseudobroadcasts:

protocol ip 192.68.34.237 broadcast

The following example enables Inverse ARP for IPX and does not send ATM pseudobroadcasts:

protocol ipx inarp no broadcast

The following example removes a static map from a VC and restores the default behavior for Inverse ARP (refer to the "Default" section described above):

no protocol ip 192.68.34.237

The following example configures PPP over Ethernet for an ATM PVC:

interface atm 2/0.1 multipoint
 pvc 0/60
  encapsulation aal5snap
  protocol pppoe

show atm pvc

To display all ATM PVCs and traffic information, use the show atm pvc privileged EXEC command.

show atm pvc [vpi/vci | name | interface atm interface-number]

Syntax Description


vpi/vci	(Optional) The ATM VPI and VCI numbers. The absence of the slash character (/) and a vpi value defaults the vpi value to 0.
name	(Optional) Name of the PVC.
interface atm interface-number	(Optional) Interface number or subinterface number of the PVC. The format slot/0[.subinterface-number multipoint] is used to specify the interface number. For a description of these arguments, refer to the interface atm command.

Command Mode

Privileged EXEC

Command History


Release	Modification
11.3(2)T	This command was first introduced.
12.0(3)DC	The PPPOE field was added.

Usage Guidelines

If the vpi/vci or name is not specified, the output of this command is the same as that of the show atm vc command but only the configured PVCs are displayed. See the first sample output below.

If the vpi/vci or name is specified, the output of this command is the same as the show atm vc vcd command, plus extra information related to PVC management including connection name, detailed states, and OAM counters. See the second sample output below.

If the interface atm interface-number option is included in the command, all PVCs under that interface or subinterface are displayed. See the third sample output below.

Examples

The following is sample output from the show atm pvc command:

Router# show atm pvc
 
	VCD/					Peak	Avg/Min	Burst
Interface	Name	VPI	VCI	Type	Encaps	Kbps	Kbps	Cells	Sts
2/0	1	0	5	PVC	SAAL	155000	155000		UP
2/0	2	0	16	PVC	ILMI	155000	155000		UP
2/0.2	101	0	50	PVC	SNAP	155000	155000		UP
2/0.2	102	0	60	PVC	SNAP	155000	155000		DOWN
2/0.2	104	0	80	PVC	SNAP	155000	155000		UP
2/0	hello	0	99	PVC	SNAP	1000			UP

The following is sample output from the show atm pvc command with the vpi/vci specified:

Router# show atm pvc 0/60
 
ATM 2/0.2: VCD 102, VPI: 0, VCI: 60
UBR, PeakRate: 155000
AAL5-LLC/SNAP, etype:0x0, Flags: 0xC20, VCmode: 0x1
OAM frequency: 3 second(s), OAM retry frequency: 1 second(s)
OAM up retry count: 3, OAM down retry count: 5
OAM Loopback status: OAM Sent
OAM VC state: Not Verified
ILMI VC state: Not Managed
VC is managed by OAM
InARP frequency: 15 minute(s)
InPkts: 1, OutPkts: 1, InBytes: 32, OutBytes: 32
InPRoc: 1, OutPRoc: 0, Broadcasts: 0
InFast: 0, OutFast:0, InAS: 0, OutAS: 0
OAM cells received: 14
F5 InEndloop: 14, F5 InSegloop: 0, F5 InAIS: 0, F5 InRDI: 0
F4 InEndloop: 0, F4 InSegloop: 0, F4 InAIS: 0, F4 InRDI: 0
OAM cells sent: 25
F5 OutEndloop: 25, F5 OutSegloop: 0, F5 OutRDI: 0
OAM cell drops: 0
PVC Discovery: NOT_VERIFIED
Status: DOWN, State: NOT_VERIFIED
PPPOE enabled

The following is sample output from the show atm pvc command with the ATM subinterface specified:

Router# show atm pvc interface atm 2/0.2
 
	VCD/					Peak	Avg/Min	Burst
Interface	Name	VPI	VCI	Type	Encaps	Kbps	Kbps	Cells	Sts
2/0.2	101	0	50	PVC	SNAP	155000	155000		UP
2/0.2	102	0	60	PVC	SNAP	155000	155000		DOWN
2/0.2	104	0	80	PVC	SNAP	155000	155000		UP

Table 1 describes significant fields shown in the displays.

**Table 1: Show ATM PVC Field Descriptions**
Field	Description
Interface	Interface and subinterface slot and port.
VCD/Name	Virtual circuit descriptor (virtual circuit number). The connection name is displayed if a name for the VC was configured using the pvc command.
VPI	Virtual path identifier.
VCI	Virtual channel identifier.
Type	Type of PVC detected from PVC discovery, either PVC-D, PVC-L, or PVC-M. PVC-D indicates a PVC created due to PVC discovery. PVC-L indicates that the corresponding peer of this PVC could not be found on the switch. PVC-M indicates that some or all of the QoS parameters of this PVC mismatch that of the corresponding peer on the switch.
Encaps	Type of ATM adaptation layer (AAL) and encapsulation.
Peak or PeakRate	Kilobits per second transmitted at the peak rate.
Avg/Min or Average Rate	Kilobits per second transmitted at the average rate.
Burst Cells	Maximum number of ATM cells the virtual circuit can transmit at peak rate.
Sts or Status	Status of the VC connection. UP indicates that the connection is enabled for data traffic. DOWN indicates that the connection is not ready for data traffic. When the Status field is DOWN, a State field is shown. See a description of the different values for this field listed later in this table. INACTIVE indicates that the interface is down.
Connection Name	The name of the PVC.
UBR, UBR+, or VBR-NRT	UBR---Unspecified Bit Rate QoS is specified for this PVC. See the ubr command for further information. UBR+---Unspecified Bit Rate QoS is specified for this PVC. See the ubr+ command for further information. VBR-NRT---Variable Bit Rate-Non Real Time QoS rates are specified for this PVC. See the vbr-nrt command for further information.
etype	Encapsulation type.
Flags	Bit mask describing virtual circuit information. The flag values are summed to result in the displayed value. 0x40---SVC 0x20---PVC 0x10---ACTIVE 0x0---AAL5-SNAP 0x1---AAL5-NLPID 0x2---AAL5-FRNLPID 0x3---AAL5-MUX 0x4---AAL3/4-SMDS 0x5---QSAAL 0x6---ILMI 0x7---AAL5-LANE 0x9---AAL5-CISCOPPP
virtual-access	Virtual-access interface identifier.
virtual-template	Virtual template identifier.
VCmode	AIP-specific or NPM-specific register describing the usage of the virtual circuit. This register contains values such as rate queue, peak rate, and AAL mode, which are also displayed in other fields.
OAM frequency	Number of seconds between sending OAM loopback cells.
OAM retry frequency	The frequency (in seconds) that end-to-end F5 loopback cells should be transmitted when a change in UP/DOWN state is being verified. For example, if a PVC is up and a loopback cell response is not received after the frequency (in seconds) specified using the oam-pvc command, then loopback cells are sent at the retry-frequency to verify whether or not the PVC is down.
OAM up retry count	Number of consecutive end-to-end F5 OAM loopback cell responses that must be received in order to change a PVC state to up. Does not apply to SVCs.
OAM down retry count	Number of consecutive end-to-end F5 OAM loopback cell responses that are not received in order to change a PVC state to down or tear down an SVC.
OAM Loopback status	Status of end-to-end F5 OAM loopback cell generation for this VC. This field will have one of the following values: OAM Disabled---End-to-End F5 OAM loopback cell generation is disabled. OAM Sent---OAM cell was sent. OAM Received---OAM cell was received. OAM Failed---OAM reply was not received within the frequency period or contained bad correlation tag.
OAM VC state	This field will have one of the following states for this VC: AIS/RDI---The VC received AIS/RDI cells. End-to-end F5 OAM loopback cells are not sent in this state. Down Retry---An OAM loopback failed. End-to-end F5 OAM loopback cells are sent at retry frequency to verify the VC is really down. After down-count unsuccessful retries, the VC goes to the Not Verified state. Not Managed---VC is not being managed by OAM. Not Verified---VC has not been verified by end-to-end F5 OAM loopback cells. AIS and RDI conditions are cleared. Up Retry---An OAM loopback was successful. End-to-end F5 OAM loopback cells are sent at retry frequency to verify the VC is really up. After up-count successive and successful loopback retries, the VC goes to the Verified state. Verified---Loopbacks are successful. AIS/RDI cell was not received.
ILMI VC state	This field will have one of the following states for this VC: Not Managed---VC is not being managed by ILMI. Not Verified---VC has not been verified by ILMI. Verified---VC has been verified by ILMI.
VC is managed by OAM/ILMI	VC is managed by OAM and/or ILMI.
InARP frequency	Number of minutes for the Inverse ARP time period.
InPkts	Total number of packets received on this virtual circuit. This number includes all fast-switched and process-switched packets.
OutPkts	Total number of packets sent on this virtual circuit. This number includes all fast-switched and process-switched packets.
InBytes	Total number of bytes received on this virtual circuit. This number includes all fast-switched and process-switched bytes.
OutBytes	Total number of bytes sent on this virtual circuit. This number includes all fast-switched and process-switched bytes.
InPRoc	Number of process-switched input packets.
OutPRoc	Number of process-switched output packets.
Broadcasts	Number of process-switched broadcast packets.
InFast	Number of fast-switched input packets.
OutFast	Number of fast-switched output packets.
InAS	Number of autonomous-switched or silicon-switched input packets.
OutAS	Number of autonomous-switched or silicon-switched output packets.
OAM cells received	Total number of OAM cells received on this virtual circuit.
F5 InEndloop	Number of end-to-end F5 OAM loopback cells received.
F5 InSegloop	Number of segment F5 OAM loopback cells received.
F5 InAIS	Number of F5 OAM AIS cells received.
F5 InRDI	Number of F5 OAM RDI cells received.
F4 InEndloop	Number of end-to-end F4 OAM loopback cells received.
F4 InSegloop	Number of segment F4 OAM loopback cells received.
F4 InAIS	Number of F4 OAM AIS cells received.
F4 InRDI	Number of F4 OAM RDI cells received.
OAM cells sent	Total number of OAM cells sent on this virtual circuit.
F5 OutEndloop	Number of end-to-end F5 OAM loopback cells sent.
F5 OutSegloop	Number of segment F5 OAM loopback cells sent.
F5 OutRDI	Number of F5 OAM RDI cells sent.
OAM cell drops	Number of OAM cells dropped (or flushed).
PVC Discovery	NOT_VERIFIED---This PVC is manually configured on the router and not yet verified with the attached adjacent switch. WELL_KNOWN---This PVC has a VCI value of 0 through 31. DISCOVERED---This PVC is learned from the attached adjacent switch via ILMI. MIXED---Some of the traffic parameters for this PVC were learned from the switch via ILMI. MATCHED---This PVC is manually configured on the router and the local traffic shaping parameters match the parameters learned from the switch. MISMATCHED---This PVC is manually configured on the router and the local traffic shaping parameters do not match the parameters learned from the switch. LOCAL_ONLY---This PVC is configured locally on the router and not on the remote switch.
State	When the Status field is UP, this field does not appear. When the Status field is DOWN or INACTIVE, the State field will appear with one of the following values: NOT_VERIFIED---The VC has been established successfully; Waiting for OAM (if enabled) and ILMI (if enabled) to verify that the VC is up. NOT_EXIST---VC has not been created. HASHING_IN---VC has been hashed into a hash table. ESTABLISHING---Ready to establish VC connection. MODIFYING---VC parameters have been modified. DELETING---VC is being deleted. DELETED---VC has been deleted. NOT_IN_SERVICE---ATM interface is shut down.
PPPOE	When PPP over Ethernet is enabled, "PPPOE enabled" appears after the status/state field.

Related Commands


Command	Description
pvc	Creates an ATM PVC on a main interface or subinterface.

virtual-template pre-clone

To specify the number of virtual-access interfaces to be created and cloned from a specific virtual template, use the virtual-template pre-clone global configuration command.

virtual-template template-number pre-clone number

Syntax Description


virtual-template template-number	The virtual template interface from which the new virtual-access interfaces are created.
pre-clone number	The number of virtual-access interfaces created.

Defaults

None

Command Mode

Global configuration

Usage Guidelines

This command applies to PPPoE only.

The number of pre-cloned virtual-access interfaces should be set to the number of expected PPPoE sessions.

Command History


Release	Modification
12.0(3)DC	This command was first introduced.

Examples

The following example creates 1200 pre-cloned virtual-access interfaces on virtual template 1:

virtual-template 1 pre-clone 1200

Debug Commands

This section documents new debug commands. All other commands used with this feature are documented in the Cisco IOS Release 12.0 command references.

debug vpdn pppoe-data

To display the contents of PPPoE session data packets, use the debug vpdn pppoe-data privileged EXEC command. Use the no form of the command to disable debugging output.

[no] debug vpdn pppoe-data

Syntax Description

This command has no arguments or keywords.

Defaults

Disabled

Command History


Release	Modification
12.0(3)DC	This command was first introduced.

Examples

The following type of output is displayed when a PPPoE data packet is transmitted by the router:

Jun 13 11:33:49.407: PPPoE: OUT
 contiguous pak, size 14
  FF 03 C0 21 02 0D 00 0A 05 06 1E 17 75 59

Related Commands


Command	Description
debug vpdn pppoe-errors	Displays PPPoE protocol and code errors.
debug vpdn pppoe-events	Displays PPPoE session events and incoming and outgoing Active Discovery Packets.
debug vpdn pppoe-packets	Displays contents of PPPoE Active Discovery Packets.

debug vpdn pppoe-errors

To display PPPoE protocol and code errors, use the debug vpdn pppoe-errors privileged EXEC command. Use the no form of the command to disable debugging output.

[no] debug vpdn pppoe-errors

Syntax Description

This command has no arguments or keywords.

Defaults

Disabled

Command History


Release	Modification
12.0(3)DC	This command was first introduced.

Examples

The following example shows output when PPPoE encounters a MAC addressing error:

Jun 13 11:33:49.407: PPPoE: Bad MAC address: 1111.2222.3333

Related Commands


Command	Description
debug vpdn pppoe-data	Displays the contents of PPPoE session data packets.
debug vpdn pppoe-events	Displays PPPoE session events and incoming and outgoing Active Discovery Packets.
debug vpdn pppoe-packets	Displays contents of PPPoE Active Discovery Packets.

debug vpdn pppoe-events

To display PPPoE session events and incoming and outgoing Active Discovery Packets, use the debug vpdn pppoe-events privileged EXEC command. Use the no form of the command to disable debugging output.

[no] debug vpdn pppoe-events

Syntax Description

This command has no arguments or keywords.

Defaults

Disabled

Command History


Release	Modification
12.0(3)DC	This command was first introduced.

Examples

The following display shows output when PPPoE established a virtual private networking session.

Jun 13 11:33:49.407: PPPOE: VPN session created.

Related Commands


Command	Description
debug vpdn pppoe-data	Displays the contents of PPPoE session data packets.
debug vpdn pppoe-errors	Displays PPPoE protocol and code errors.
debug vpdn pppoe-packets	Displays contents of PPPoE Active Discovery Packets.

debug vpdn pppoe-packets

To display contents of PPPoE active discovery packets, use the debug vpdn pppoe-packets privileged EXEC command. Use the no form of the command to disable debugging output.

[no] debug vpdn pppoe-packets

Syntax Description

This command has no arguments or keywords.

Defaults

Disabled

Command History


Release	Modification
12.0(3)DC	This command was first introduced.

Examples

The following example shows output when PPPoE encounters an active discovery packet.

Jun 13 11:33:49.407: PPPoE: discovery packet
 contiguous pak, size 74
  00 04 09 00 AA AA 03 00 80 C2 00 07 00 00 00 00
  22 22 33 33 00 50 73 27 5D C3 88 63 11 65 00 01
  00 1C 01 01 00 00 01 02 00 0A 70 70 70 6F 65 00
  .....

Related Commands


Command	Description
debug vpdn pppoe-data	Displays the contents of PPPoE session data packets.
debug vpdn pppoe-errors	Displays PPPoE protocol and code errors.
debug vpdn pppoe-events	Displays PPPoE session events and incoming and outgoing Active Discovery Packets.

Glossary

AAL5---ATM Adaptation Layer 5. One of four AALs recommended by the ITU-T. AAL5 is used predominantly for the transfer of packet-based traffic.

active discovery packet---a type of packet used by PPPoE during the discovery stage.

ATM---Asynchronous Transfer Mode. International standard for cell relay in which multiple service types (such as voice, video, or data) are conveyed in fixed-length (53-byte) cells.

CEF---Cisco Express Forwarding. Advanced Layer 3 IP switching technology that optimizes network performance and scalability for networks with large and dynamic traffic patterns, such as the Internet, on networks characterized by intensive Web-based applications, or interactive sessions.

LLC---logical link control. Higher of the two data link layer sublayers defined by the IEEE. The LLC sublayer handles error control, flow control, framing, and MAC-sublayer addressing.

MTU---maximum transmission unit. Maximum packet size, in bytes, that a particular interface can handle.

PPP---Point-to-Point Protocol. Successor to SLIP that provides router-to-router and host-to-network connections over synchronous and asynchronous circuits.

PPPoE---Point-to-Point Protocol over Ethernet. Encapsulation of PPP packets over Ethernet that provides the ability to extend a PPP session from a remote access concentrator to an Ethernet attached host. With this model, each host utilizes its own PPP stack and the user is presented with a familiar user interface. Access control, billing and type of service can be done on a per-user, rather than a per-site, basis.

PVC---permanent virtual circuit. Virtual circuit that is permanently established. PVCs save bandwidth associated with circuit establishment and tear down in situations where certain virtual circuits must exist all the time. Also called a permanent virtual connection in ATM terminology.

SNAP---Subnetwork Access Protocol. Internet protocol that operates between a network entity in the subnetwork and a network entity in the end system. SNAP specifies a standard method of encapsulating IP datagrams and ARP messages on IEEE networks.

SVC---switched virtual circuit. Virtual circuit that is dynamically established on demand and is torn down when transmission is complete. SVCs are used in situations where data transmission is sporadic. Also called a switched virtual connection in ATM terminology.

VC---virtual circuit. Logical circuit created to ensure reliable communication between two network devices. A virtual circuit is defined by a VPI/VCI pair, and can be either permanent (PVC) or switched (SVC). In ATM terminology, a virtual circuit is also called a virtual channel.

VCI---virtual channel identifier. Sixteen-bit field in the header of an ATM cell. The VCI, together with the VPI, is used to identify the next destination of a cell as it passes through a series of ATM switches on its way to its destination.

virtual-access interface---Instance of a unique virtual interface that is created dynamically and exists temporarily. Virtual-access interfaces can be created and configured differently by different applications, such as virtual profiles and virtual private dial-up networks. Virtual-access interfaces are cloned from virtual template interfaces.

virtual template interface---A logical interface configured with generic configuration information for a specific purpose or configuration common to specific users, plus router-dependent information. The template takes the form of a list of Cisco IOS interface commands that are applied to virtual-access interfaces, as needed.

VPDN---Virtual Private Dial-up Networking. A system that permits dial-in networks to exist remotely to home networks, while giving the appearance of being directly connected.

VPI---virtual path identifier. Eight-bit field in the header of an ATM cell. The VPI, together with the VCI, is used to identify the next destination of a cell as it passes through a series of ATM switches on its way to its destination.

Table of Contents

PPP over Ethernet

Feature Overview