L2TP commands -- allow l2tp

Use allow l2tp to configure an L2TP network server (LNS) to accept Layer 2 Tunneling Protocol (L2TP) tunneling requests from an L2TP access concentrator (LAC), and to specify a VT interface for tunnel setup.

Use undo allow to restore the default.

Syntax

allow l2tp virtual-template virtual-template-number [ remote remote-name ]

undo allow

Default

An LNS denies L2TP tunneling requests from any LACs.

Views

L2TP group view

Predefined user roles

network-admin

mdc-admin

Parameters

virtual-template virtual-template-number: Specifies a VT interface by its number. The value range for the virtual-template-number argument varies by device model. An LNS dynamically creates virtual access (VA) interfaces based on the configuration of a VT interface. Each VA interface is used to carry data for a different L2TP session.

remote remote-name: Specifies the name of the tunnel peer (LAC) initiating tunneling requests, a case-sensitive string of 1 to 31 characters.

Usage guidelines

The allow l2tp command is available only on L2TP groups in LNS mode.

Make sure the specified name of the tunnel peer is consistent with the local name configured on the LAC.

If you execute this command multiple times for an L2TP group, the most recent configuration takes effect.

For L2TP group 1, if you do not specify the remote remote-name option, an LNS accepts tunneling requests from any LACs. In this case, L2TP group 1 acts as the default L2TP group. For L2TP groups other than L2TP group 1, the remote remote-name option must be configured.

The allow l2tp command is available only on LNSs.

· When an LAC that initiates a tunneling request is the tunnel peer configured in an L2TP group, the LNS uses the tunnel parameters configured in this group for tunnel setup.

· When the LAC is not the tunnel peer configured in any L2TP group, the LNS performs one of the following operations:

?span style='font:7.0pt "Times New Roman"'> Uses the tunnel parameters for the default L2TP group if it exists.

?span style='font:7.0pt "Times New Roman"'> Fails to set up a tunnel with the LAC if the default L2TP group does not exist.

As a best practice, configure a default L2TP group on the LNS in the following cases:

· LACs (such as hosts with Windows 2000 Beta 2 installed) include blank local names in their tunneling requests.

· The LNS sets up tunnels with multiple LACs by using the same tunnel parameters.

Examples

# Specify L2TP group 1 as the default L2TP group, and specify Virtual-Template 1 for tunnel setup. For L2TP group 2, configure the LNS to accept the L2TP tunneling request initiated by the peer (LAC) named aaa, and specify Virtual-Template 2 for tunnel setup.

<Sysname> system-view

[Sysname] l2tp-group 1 mode lns

[Sysname-l2tp1] allow l2tp virtual-template 1

[Sysname-l2tp1] quit

[Sysname] l2tp-group 2 mode lns

[Sysname-l2tp2] allow l2tp virtual-template 2 remote aaa

Related commands

tunnel name

L2TP commands -- bandwidth

Use bandwidth to set the expected bandwidth for an interface.

Use undo bandwidth to restore the default.

Syntax

bandwidth bandwidth-value

undo bandwidth

Default

The expected bandwidth (in kbps) is interface baudrate divided by 1000.

Views

Virtual PPP interface view

Predefined user roles

network-admin

mdc-admin

Parameters

bandwidth-value: Specifies the expected bandwidth in the range of 1 to 400000000 kbps.

Usage guidelines

The expected bandwidth of an interface affects the link costs in OSPF, OSPFv3, and IS-IS. For more information, see Layer 3—IP Routing Configuration Guide.

Examples

# Set the expected bandwidth of Virtual-PPP 10 to 100 kbps.

<Sysname> system-view

[Sysname] interface virtual-ppp 10

[Sysname-Virtual-PPP10] bandwidth 100

L2TP commands -- default

Use default to restore the default settings for a virtual PPP interface.

Syntax

default

Views

Virtual PPP interface view

Predefined user roles

network-admin

mdc-admin

Usage guidelines

| CAUTION: The default command might interrupt ongoing network services. Make sure you are fully aware of the impact of this command when you execute it on a live network.

‌

This command might fail to restore the default settings for some commands for reasons such as command dependencies or system restrictions. Use the display this command in interface view to identify these commands. Use the undo forms of these commands or follow the command reference to individually restore their default settings. If your restoration attempt still fails, follow the error message instructions to resolve the problem.

Examples

# Restore the default settings for Virtual-PPP 10.

<Sysname> system-view

[Sysname] interface virtual-ppp 10

[Sysname-Virtual-PPP10] default

L2TP commands -- description

Use description to configure the description of an interface.

Use undo description to restore the default.

Syntax

description text

undo description

Default

The description of an interface is the interface-name plus Interface. For example, the default description of Virtual-PPP254 is Virtual-PPP254 Interface.

Views

Virtual PPP interface view

Predefined user roles

network-admin

mdc-admin

Parameters

text: Specifies the interface description, a case-sensitive string of 1 to 255 characters.

Examples

# Set the description of Virtual-PPP 10 to virtual-interface.

<Sysname> system-view

[Sysname] interface virtual-ppp 10

[Sysname-Virtual-PPP10] description virtual-interface

L2TP commands -- display interface virtual-ppp

Use display interface virtual-ppp to display information about virtual PPP interfaces.

Syntax

display interface [ virtual-ppp [ interface-number ] ] [ brief [ description | down ] ]

Views

Any view

Predefined user roles

network-admin

network-operator

mdc-admin

mdc-operator

Parameters

virtual-ppp [ interface-number ]: Specifies an existing virtual PPP interface by its number in the range of 0 to 255. If you do not specify the virtual-ppp keyword, this command displays information about all interfaces. If you specify the virtual-ppp keyword but you do not specify an interface, this command displays information about all virtual PPP interfaces.

brief: Displays brief interface information. If you do not specify this keyword, the command displays detailed interface information.

description: Displays complete interface descriptions. If you do not specify this keyword, the command displays only the first 27 characters of each interface description.

down: Displays information about the interfaces in physically down state and the causes. If you do not specify this keyword, the command displays information about interfaces in any state.

Examples

# Display detailed information about Virtual-PPP 10.

<Sysname> display interface virtual-ppp 10

Virtual-PPP10

Current state: Administratively DOWN

Line protocol state: DOWN

Description: Virtual-PPP10 Interface

Bandwidth: 100000kbps

Maximum Transmit Unit: 1500

Hold timer: 10 seconds, retry times: 5

Internet Address is 10.0.0.1/24 Primary

Link layer protocol: PPP

LCP: initial

Physical: L2TP, baudrate: 100000000 bps

Last clearing of counters: Never

Last 300 seconds input rate: 0 bytes/sec, 0 bits/sec, 0 packets/sec

Last 300 seconds output rate: 0 bytes/sec, 0 bits/sec, 0 packets/sec

Input: 154 packets, 1880 bytes, 0 drops

Output: 155 packets, 1875 bytes, 0 drops

Table 1 Command output

Field | Description
Current state | Physical link state of the interface: · Administratively DOWN—The interface has been shut down by using the shutdown command. · DOWN—The interface is administratively up, but its physical state is down (possibly because no physical link exists or the link has failed). · UP—The interface is up both administratively and physically.
Line protocol state | Data link layer state of the interface. The state is determined through automatic parameter negotiation at the data link layer. · UP—The data link layer protocol is up. · UP (spoofing)—The data link layer protocol is up, but the link is an on-demand link or does not exist. This attribute is typical of null interfaces and loopback interfaces. · DOWN—The data link layer protocol is down.
Bandwidth | Expected bandwidth of the interface.
Hold timer | Interval in seconds for the interface to send keepalive packets.
retry times | Maximum number of keepalive retransmission attempts. A link is removed after the maximum number of retransmission attempts is reached.
Internet protocol processing: Disabled | The interface is not assigned an IP address and cannot process IP packets.
Internet Address | IP address of the interface. The primary attribute indicates that the address is the primary IP address.
Link layer protocol | Link layer protocol of the interface: PPP.
Physical | Physical type of the interface: L2TP.
baudrate | Baud rate of the interface.
Last clearing of counters | Time when the reset counters interface command was last used to clear the interface statistics. This field displays Never if the reset counters interface command has never been used on the interface since device startup.
Last 300 seconds input rate: 0 bytes/sec, 0 bits/sec, 0 packets/sec | Average rate of inbound traffic in the last 300 seconds.
Last 300 seconds output rate: 0 bytes/sec, 0 bits/sec, 0 packets/sec | Average rate of outbound traffic in the last 300 seconds.
Input: 154 packets, 1880 bytes, 0 drops | Total number of inbound packets, total number of inbound bytes, and total number of dropped inbound packets.
Output: 155 packets, 1875 bytes, 0 drops | Total number of outbound packets, total number of outbound bytes, and total number of dropped outbound packets.

‌

# Display summary information about virtual PPP interface Virtual-PPP 10.

<Sysname> display interface virtual-ppp 10 brief

Brief information on interfaces in route mode:

Link: ADM - administratively down; Stby - standby

Protocol: (s) - spoofing

Interface Link Protocol Primary IP Description

VPPP10 ADM DOWN 10.0.0.1

# Display information about the virtual PPP interfaces in physically down state and the causes.

<Sysname> display interface virtual-ppp brief down

Brief information on interfaces in route mode:

Link: ADM - administratively down; Stby - standby

Interface Link Cause

VPPP9 ADM Administratively

VPPP10 ADM Administratively

VPPP12 ADM Administratively

# Display summary information about virtual PPP interface Virtual-PPP 10, including the complete interface description.

<Sysname> display inter Virtual-PPP 10 brief description

Brief information on interfaces in route mode:

Link: ADM - administratively down; Stby - standby

Protocol: (s) - spoofing

Interface Link Protocol Primary IP Description

VPPP10 ADM DOWN 10.0.0.1

Table 2 Command output

Field | Description
The brief information of interfaces in route mode/Brief information on interfaces in route mode | Summary information about Layer 3 interfaces.
Interface | Abbreviated interface name.
Link | Physical link state of the interface: · UP—The interface is physically up. · DOWN—The interface is physically down. · ADM—The interface has been shut down by using the shutdown command. To restore the physical state of the interface, use the undo shutdown command. · Stby—The interface is a backup interface in standby state. To see the primary interface, use the display interface-backup state command.
Protocol | Data link layer protocol state of the interface: · UP—The data link layer protocol of the interface is up. · DOWN—The data link layer protocol of the interface is down. · UP(s)—The data link layer protocol of the interface is up, but the link is an on-demand link or does not exist. The (s) attribute represents the spoofing flag. This value is typical of null interfaces and loopback interfaces.
Primary IP | Primary IP address of the interface. This field displays two hyphens (--) if the interface does not have an IP address.
Description | Description of the interface.
Cause | Cause for the physical link state of an interface to be DOWN: · Administratively—The interface has been manually shut down by using the shutdown command. To restore the physical state of the interface, use the undo shutdown command. · Not connected—No physical connection exists (possibly because the network cable is disconnected or faulty).

‌

L2TP commands -- display l2tp session

Use display l2tp session to display information about L2TP sessions.

Syntax

display l2tp session [ statistics ]

Views

Any view

Predefined user roles

network-admin

network-operator

mdc-admin

mdc-operator

Parameters

statistics: Displays statistics for L2TP sessions.

Examples

# Display statistics for L2TP sessions.

<Sysname> display l2tp session statistics

Total number of sessions: 1

# Display information about L2TP sessions.

<Sysname> display l2tp session

LocalSID RemoteSID LocalTID State

89 36245 10878 Established

Table 3 Command output

Field | Description
LocalSID | Local session ID.
RemoteSID | Remote session ID.
LocalTID | Local tunnel ID.
State | Session state: · Idle. · Wait-tunnel—Waits for the tunnel to be established. · Wait-reply—Waits for an Incoming-Call-Reply (ICRP) message indicating the call is accepted. · Wait-connect—Waits for an Incoming-Call-Connected (ICCN) message. · Established.

‌

L2TP commands -- display l2tp session temporary

Use display l2tp session temporary to display information about temporary L2TP sessions.

Syntax

display l2tp session temporary

Views

Any view

Predefined user roles

network-admin

Examples

# Display information about temporary L2TP sessions.

<Sysname> display l2tp session temporary

Total number of temporary sessions: 6

LocalSID RemoteSID LocalTID State

2298 0 19699 Wait-tunnel

42805 0 19699 Wait-tunnel

17777 0 19699 Wait-tunnel

58284 0 19699 Wait-tunnel

33256 0 19699 Wait-tunnel

8228 0 19699 Wait-tunnel

Table 4 Command output

Field | Description
LocalSID | Local session ID.
RemoteSID | Remote session ID.
LocalTID | Local tunnel ID.
State | Session state: · Idle. · Wait-tunnel—Waits for the tunnel to be established. · Wait-reply—Waits for an ICRP message indicating the call is accepted. · Wait-connect—Waits for an ICCN message.

‌

L2TP commands -- display l2tp tunnel

Use display l2tp tunnel to display information about L2TP tunnels.

Syntax

display l2tp tunnel [ statistics ]

Views

Any view

Predefined user roles

network-admin

network-operator

mdc-admin

mdc-operator

Parameters

statistics: Displays statistics for L2TP tunnels.

Examples

# Display statistics for L2TP tunnels.

<Sysname> display l2tp tunnel statistics

Total number of tunnels: 1

# Display information about L2TP tunnels.

<Sysname> display l2tp tunnel

LocalTID RemoteTID State Sessions RemoteAddress RemotePort RemoteName

10878 21 Established 1 20.1.1.2 1701 lns

Table 5 Command output

Field | Description
LocalTID | Local tunnel ID.
RemoteTID | Remote tunnel ID.
State | Tunnel state: · Idle. · Wait-reply. · Wait-connect. · Established. · Stopping.
Sessions | Number of sessions within the tunnel.
RemoteAddress | IP address of the peer.
RemotePort | UDP port number of the peer.
RemoteName | Name of the tunnel peer.

‌

Related commands

reset l2tp tunnel

L2TP commands -- display l2tp va-pool

Use display l2tp va-pool to display information about L2TP VA pools.

Syntax

display l2tp va-pool

Views

Any view

Predefined user roles

network-admin

network-operator

mdc-admin

mdc-operator

Examples

# Display information about L2TP VA pools.

<Sysname> display l2tp va-pool

VT interface Size Unused State

Virtual-Template1 1000 900 Normal

Table 6 Command output

Field | Description
VT interface | VT interface that uses the VA pool.
Size | VA pool capacity set for L2TP users.
Unused | VA pool capacity available for L2TP users.
State | Current state of the VA pool: · Creating—The VA pool is being created. · Destroying—The VA pool is being removed. · Normal—The VA pool has been created.

‌

Related commands

l2tp virtual-template va-pool

L2TP commands -- interface virtual-ppp

Use interface virtual-ppp to create a virtual PPP interface and enter its view, or enter the view of an existing virtual PPP interface.

Use undo interface virtual-ppp to delete a virtual PPP interface.

Syntax

interface virtual-ppp interface-number

undo interface virtual-ppp interface-number

Default

No virtual PPP interface exists.

Views

System view

Predefined user roles

network-admin

mdc-admin

Parameters

interface-number: Specifies a virtual PPP interface by its number in the range of 0 to 255.

Usage guidelines

A virtual PPP interface is required on the LAC for establishing an LAC-auto-initiated L2TP tunnel.

Examples

# Create Virtual-PPP 10 and enter its view.

<Sysname> system-view

[Sysname] interface virtual-ppp 10

[Sysname-Virtual-PPP10]

L2TP commands -- ip dscp

Use ip dscp to set the DSCP value of L2TP packets.

Use undo ip dscp to restore the default.

Syntax

ip dscp dscp-value

undo ip dscp

Default

The DSCP value of L2TP packets is 0.

Views

L2TP group view

Predefined user roles

network-admin

mdc-admin

Parameters

dscp-value: Specifies the DSCP value of L2TP packets, in the range of 0 to 63.

Usage guidelines

The DSCP field is the first 6 bits of the IP ToS byte. This field marks the priority of IP packets for forwarding. This command sets the DSCP value for the IP packet when L2TP encapsulates a PPP frame into an IP packet.

Examples

# Set the DSCP value of L2TP packets to 50.

<Sysname> system-view

[Sysname] l2tp-group 1 mode lac

[Sysname-l2tp1] ip dscp 50

L2TP commands -- l2tp enable

Use l2tp enable to enable L2TP.

Use undo l2tp enable to disable L2TP.

Syntax

l2tp enable

undo l2tp enable

Default

L2TP is disabled.

Views

System view

Predefined user roles

network-admin

mdc-admin

Usage guidelines

For L2TP configurations to take effect, you must enable L2TP.

Examples

# Enable L2TP.

<Sysname> system-view

[Sysname] l2tp enable

L2TP commands -- l2tp tsa-id

Use l2tp tsa-id to set the TSA ID for the L2TP tunnel switching (LTS) device and enable L2TP loop detection on the LTS device.

Use undo l2tp tsa-id to restore the default.

Syntax

l2tp tsa-id tsa-id

undo l2tp tsa-id

Default

The TSA ID of the LTS device is not set, and L2TP loop detection is disabled on the LTS device.

Views

System view

Predefined user roles

network-admin

mdc-admin

Parameters

tsa-id: Specifies a TSA ID that uniquely identifies the LTS device. This argument is a case-sensitive string of 1 to 64 characters.

Usage guidelines

The LTS device compares the configured TSA ID with each TSA ID Attribute Value Pair (AVP) in a received ICRQ packet for loop detection.

· If a match is found, a loop exists. The LTS immediately tears down the session.

· If no match is found, the LTS performs the following operations:

a. Encapsulates the configured TSA ID into a new TSA ID AVP.

b. Appends the new TSA ID AVP to the packet.

c. Sends the packet to the next hop LTS.

To avoid loop detection errors, make sure the TSA ID of each LTS device is unique.

Examples

# Set the TSA ID of the LTS device to lts0, and enable L2TP loop detection on the LTS device.

<Sysname> system-view

[Sysname] l2tp tsa-id lts0

L2TP commands -- l2tp virtual-template va-pool

Use l2tp virtual-template va-pool to create a VA pool.

Use undo l2tp virtual-template va-pool to delete a VA pool.

Syntax

l2tp virtual-template template-number va-pool va-volume

undo l2tp virtual-template template-number va-pool

Default

No VA pool exists.

Views

System view

Predefined user roles

network-admin

mdc-admin

Parameters

virtual-template template-number: Specifies an existing VT interface by its number to use the VA pool.

va-pool va-volume: Specifies the maximum number of VA interfaces contained in the VA pool, in the range of 1 to 65534.

Usage guidelines

The LNS creates a VA interface for an L2TP session to exchange packets with the LAC, and it deletes the VA interface when the user goes offline. Creating and deleting VA interfaces take time. If a large number of users are coming online or going offline, the performance of L2TP connection establishment and termination will be degraded.

You can configure a VA pool to improve the performance. A VA pool contains a group of VA interfaces. The LNS selects a VA interface from the pool for a requesting user and places the interface back to the VA pool when the user goes offline. This mechanism speeds up the establishment and termination of L2TP connections. When a VA pool is exhausted, the system still creates a VA interface for an L2TP connection and deletes it when the user goes offline.

When you configure a VA pool, follow these guidelines:

· A VT interface can be associated with only one VA pool. To change the capacity of a VA pool, delete the previous configuration, and reconfigure the VA pool.

· Creating or deleting a VA pool takes time. During the process of creating or deleting a VA pool, users can come online or go offline, but the VA pool does not take effect.

· The system might create a VA pool that contains VA interfaces less than the specified number because of insufficient resources. In this case, you can use the display l2tp va-pool command to view the number of available VA interfaces and current state of the VA pool.

· Create a VA pool with an appropriate capacity, because a VA pool occupies much system memory.

· Deleting a VA pool does not log off the users who are using VA interfaces in the VA pool.

Examples

# Create a VA pool with a capacity of 1000 VA interfaces for Virtual-template 2.

<Sysname> system-view

[Sysname] l2tp virtual-template 2 va-pool 1000

Related commands

display l2tp va-pool

L2TP commands -- l2tp-auto-client

Use l2tp-auto-client to trigger an LAC to automatically establish an L2TP tunnel.

Use undo l2tp-auto-client to delete the automatically established L2TP tunnel.

Syntax

l2tp-auto-client l2tp-group group-number

undo l2tp-auto-client

Default

An LAC does not automatically establish an L2TP tunnel.

Views

Virtual PPP interface view

Predefined user roles

network-admin

mdc-admin

Parameters

l2tp-group group-number: Specifies an L2TP group by its number in the range of 1 to 65535. The LAC uses tunnel parameters of the L2TP group to establish the tunnel.

Usage guidelines

The L2TP group specified must be an existing one in LAC mode.

An L2TP tunnel automatically established in LAC-auto-initiated mode exists until you delete the tunnel by using the undo l2tp-auto-client or undo l2tp-group group-number command.

Examples

# Trigger the LAC to automatically establish an L2TP tunnel by using the tunnel parameters of L2TP group 10.

<Sysname> system-view

[Sysname] interface virtual-ppp 1

[Sysname-Virtual-PPP1] l2tp-auto-client l2tp-group 10

Related commands

l2tp-group

L2TP commands -- l2tp-group

Use l2tp-group to create an L2TP group and enter its view, or enter the view of an existing L2TP group.

Use undo l2tp-group to delete an L2TP group.

Syntax

l2tp-group group-number [ mode { lac | lns } ]

undo l2tp-group group-number

Default

No L2TP group exists.

Views

System view

Predefined user roles

network-admin

mdc-admin

Parameters

group-number: Specifies an L2TP group by its number in the range of 1 to 65535.

mode: Specifies a mode for the L2TP group.

lac: Specifies the LAC mode.

lns: Specifies the LNS mode.

Usage guidelines

To create a new L2TP group, you must specify the mode keyword. To enter the view of an existing L2TP group, you do not need to specify this keyword.

In L2TP group view, you can configure L2TP tunnel parameters, such as tunnel authentication and flow control.

A device can have L2TP groups in both LAC and LNS modes at the same time.

Examples

# Create L2TP group 2 in LAC mode, and enter its view.

<Sysname> system-view

[Sysname] l2tp-group 2 mode lac

[Sysname-l2tp2]

Related commands

allow l2tp

lns-ip

user

L2TP commands -- lns-ip

Use lns-ip to specify LNS IP addresses on an LAC.

Use undo lns-ip to remove the specified LNS IP addresses on an LAC.

Syntax

lns-ip { ip-address }&<1-5>

undo lns-ip

Default

No LNS IP addresses are specified on an LAC.

Views

L2TP group view

Predefined user roles

network-admin

mdc-admin

Parameters

{ ip-address }&<1-5>: Specifies LNS IP addresses. &<1-5> indicates that you can enter a maximum of five IP addresses.

Usage guidelines

The LAC initiates an L2TP tunneling request to its specified LNSs consecutively in their configuration order until it receives an acknowledgment from an LNS. The LNS then becomes the tunnel peer.

The lns-ip command is available only on L2TP groups in LAC mode.

If you execute this command multiple times for an L2TP group, the most recent configuration takes effect.

Examples

# Specify the LNS IP address as 202.1.1.1.

<Sysname> system-view

[Sysname] l2tp-group 1 mode lac

[Sysname-l2tp1] lns-ip 202.1.1.1

L2TP commands -- mandatory-chap

Use mandatory-chap to force the LNS to perform CHAP authentication for users.

Use undo mandatory-chap to restore the default.

Syntax

mandatory-chap

undo mandatory-chap

Default

An LNS does not perform CHAP authentication for users.

Views

L2TP group view

Predefined user roles

network-admin

mdc-admin

Usage guidelines

The LNS uses the LAC as an authentication proxy. The LAC sends the LNS all user authentication information from users and the authentication method configured on the LAC itself. The LNS then checks the user validity according to the received information and the locally configured authentication method.

When mandatory CHAP authentication is configured, a user who depends on an LAC to initiate tunneling requests is authenticated by both the LAC and the LNS for increased security. Some users might not support the authentication on the LNS. In this situation, do not configure this command, because CHAP authentication on the LNS will fail.

This command is available only on L2TP groups in LNS mode.

This command takes effect only on NAS-initiated L2TP tunnels.

The mandatory-lcp command takes precedence over this command. If both commands are configured for an L2TP group, the LNS performs LCP renegotiation with the user.

Examples

# Force the LNS to perform CHAP authentication for users.

<Sysname> system-view

[Sysname] l2tp-group 1 mode lns

[Sysname-l2tp1] mandatory-chap

Related commands

mandatory-lcp

L2TP commands -- mandatory-lcp

Use mandatory-lcp to force an LNS to perform LCP negotiation with users.

Use undo mandatory-lcp to restore the default.

Syntax

mandatory-lcp

undo mandatory-lcp

Default

An LNS does not perform LCP negotiation with users.

Views

L2TP group view

Predefined user roles

network-admin

mdc-admin

Usage guidelines

By default, to establish a NAS-initiated tunnel, the user performs LCP negotiation with the LAC. If the negotiation succeeds, the LAC initiates a tunneling request and sends the negotiation results (including authentication information) to the LNS. Then, the LNS determines whether the user is valid based on the information received instead of performing LCP renegotiation with the user.

If you do not expect the LNS to accept LCP negotiation parameters, configure this command to perform an LCP negotiation between the LNS and the user. In this case, the information sent by the LAC will be ignored.

Some users might not support LCP negotiation. In this case, do not configure this command because LCP negotiation will fail.

This command is available only on L2TP groups in LNS mode.

This command takes effect only on NAS-initiated L2TP tunnels.

This command takes precedence over the mandatory-chap command. If both commands are configured for an L2TP group, the LNS performs LCP negotiation with the user.

Examples

# Force an LNS to perform LCP negotiation with users.

<Sysname> system-view

[Sysname] l2tp-group 1 mode lns

[Sysname-l2tp1] mandatory-lcp

Related commands

mandatory-chap

L2TP commands -- mtu

Use mtu to set the MTU size of an interface.

Use undo mtu to restore the default.

Syntax

mtu size

undo mtu

Default

The MTU size of a virtual PPP interface is 1500 bytes.

Views

Virtual PPP interface view

Predefined user roles

network-admin

mdc-admin

Parameters

size: Specifies the MTU size in bytes. The value range varies by device model.

Usage guidelines

The MTU size of an interface affects the fragmentation and reassembly of IP packets on the interface.

For the configured MTU size to take effect, you must execute the shutdown command and then the undo shutdown command on the interface.

Examples

# Set the MTU size of Virtual-PPP 10 to 1400 bytes.

<Sysname> system-view

[Sysname] interface virtual-ppp 10

[Sysname-Virtual-PPP10] mtu 1400

L2TP commands -- reset counters interface virtual-ppp

Use reset counters interface virtual-ppp to clear the statistics for virtual PPP interfaces.

Syntax

reset counters interface [ virtual-ppp [ interface-number ] ]

Views

User view

Predefined user roles

network-admin

mdc-admin

Parameters

virtual-ppp [ interface-number ]: Specifies a virtual PPP interface by its number in the range of 0 to 255. If you specify neither virtual-ppp nor interface-number, this command clears the statistics for all interfaces. If you specify virtual-ppp but not interface-number, this command clears the statistics for all virtual PPP interfaces. If you specify both virtual-ppp and interface-number, this command clears the statistics for the specified virtual PPP interface.

Usage guidelines

Use this command to clear history statistics if you want to collect traffic statistics for a specific time period.

Examples

# Clear the statistics for Virtual-PPP 10.

<Sysname> reset counters interface virtual-ppp 10

L2TP commands -- reset l2tp tunnel

Use reset l2tp tunnel to disconnect tunnels and all sessions within the tunnels.

Syntax

reset l2tp tunnel { id tunnel-id | name remote-name }

Views

User view

Predefined user roles

network-admin

mdc-admin

Parameters

id tunnel-id: Specifies a tunnel by its local ID in the range of 1 to 65535.

name remote-name: Specifies L2TP tunnels by the tunnel peer name, a case-sensitive string of 1 to 31 characters.

Usage guidelines

When the number of user connections is 0 or a network fault occurs, you can disconnect the L2TP tunnel by using this command on either the LAC or LNS. After the tunnel is disconnected, all sessions within it are disconnected.

If you specify a tunnel peer name, all tunnels with the tunnel peer name will be disconnected. If no tunnel with the tunnel peer name exists, nothing happens.

A tunnel disconnected by force can be re-established when a client makes a call.

Examples

# Disconnect all tunnels with the tunnel peer name of aaa.

<Sysname> reset l2tp tunnel name aaa

Related commands

display l2tp tunnel

L2TP commands -- service

| NOTE: Support for this command depends on the device model.

‌

Use service to specify a traffic processing slot for a virtual PPP interface.

Use undo service to restore the default.

Syntax

Distributed devices in standalone mode:Centralized IRF devices:

service slot slot-number

undo service slot

Distributed devices in IRF mode:

service chassis chassis-number slot slot-number

undo service chassis

Default

No traffic processing slot is specified for a virtual PPP interface. Traffic on a virtual PPP interface is processed on the slot at which the traffic arrives.

Views

Virtual PPP interface view

Predefined user roles

network-admin

mdc-admin

Parameters

slot slot-number: Specifies a card by its slot number. (Distributed devices in standalone mode.)

slot slot-number: Specifies an IRF member device by its member ID. (Centralized IRF devices.) (IRF 3 incapable.)

slot slot-number: Specifies an IRF member device by its member ID or specifies a PEX by its virtual slot number. (Centralized IRF devices.) (IRF 3 capable.)

chassis chassis-number slot slot-number: Specifies a card on an IRF member device. The chassis-number argument represents the member ID of the IRF member device. The slot-number argument represents the slot number of the card. (Distributed devices in IRF mode.) (IRF 3 incapable.)

chassis chassis-number slot slot-number: Specifies a card on an IRF member device or specifies a PEX. The chassis-number argument represents the member ID of the IRF member device or the virtual chassis number of the PEX. The slot-number argument represents the slot number of the card or PEX. (Distributed devices in IRF mode.) (IRF 3 capable.)

Usage guidelines

This command is supported on distributed devices and IRF-capable centralized devices.

Specify a traffic processing slot if a feature (for example, IPsec antireplay) requires that all traffic on a tunnel interface be processed on the same slot.

Make sure the specified traffic processing slot is available. If the specified traffic processing slot is unavailable, traffic on the virtual PPP interface cannot be forwarded, whether or not the virtual PPP interface is up. Traffic on the virtual PPP interface will not be forwarded until the traffic processing slot becomes available or until you respecify an available traffic processing slot.

Examples

# Specify a traffic processing slot for Virtual-PPP 10.

<Sysname> system-view

[Sysname] interface virtual-ppp 10

[Sysname-Virtual-PPP10] service slot 2

L2TP commands -- shutdown

Use shutdown to shut down a virtual PPP interface.

Use undo shutdown to bring up a virtual PPP interface.

Syntax

shutdown

undo shutdown

Default

A virtual PPP interface is up.

Views

Virtual PPP interface view

Predefined user roles

network-admin

mdc-admin

Examples

# Shut down Virtual-PPP 10.

<Sysname> system-view

[Sysname] interface virtual-ppp 10

[Sysname-Virtual-PPP10] shutdown

L2TP commands -- source-ip

Use source-ip to configure the source IP address of L2TP tunnel packets.

Use undo source-ip to restore the default.

Syntax

source-ip ip-address

undo source-ip

Default

The source IP address of L2TP tunnel packets is the IP address of the egress interface.

Views

L2TP group view

Predefined user roles

network-admin

mdc-admin

Parameters

ip-address: Specifies the source IP address of L2TP tunnel packets.

Usage guidelines

This command is available only on an L2TP group in LAC mode.

For high availability, as a best practice, use the IP address of a loopback interface as the source IP address of L2TP tunnel packets.

When L2TP is enabled for a VSRP group, the following rules apply:

· If both tunnel vsrp source-ip and source-ip commands are configured in L2TP group view, the tunnel vsrp source-ip command takes effect.

· If only the source-ip command is configured in L2TP group view, an L2TP VSRP failure occurs.

For more information about L2TP VSRP, see High Availability Configuration Guide.

Examples

# Configure the source IP address of L2TP tunnel packets as 2.2.2.2.

<Sysname> system-view

[Sysname] l2tp-group 1 mode lac

[Sysname-l2tp1] source-ip 2.2.2.2

Related commands

tunnel vsrp source-ip (High Availability Command Reference)

L2TP commands -- timer-hold

Use timer-hold to set the keepalive interval.

Use undo timer-hold to restore the default.

Syntax

timer-hold seconds

undo timer-hold

Default

The keepalive interval is 10 seconds.

Views

Virtual PPP interface view

Predefined user roles

network-admin

mdc-admin

Parameters

seconds: Specifies the interval at which the LAC or the LNS sends keepalive packets, in the range of 0 to 32767 seconds.

Usage guidelines

A virtual PPP interface sends keepalive packets at keepalive intervals to detect the availability of the peer. If the interface fails to receive keepalive packets when the keepalive retry limit is reached, it determines that the link fails and reports a link layer down event.

To set the keepalive retry limit, use the timer-hold retry command.

On a slow link, increase the keepalive interval to prevent false shutdown of the interface. This situation might occur when keepalive packets are delayed because a large packet is being transmitted on the link.

Examples

# Set the keepalive interval to 20 seconds for Virtual-PPP 10.

<Sysname> system-view

[Sysname] interface virtual-ppp 10

[Sysname-Virtual-PPP10] timer-hold 20

Related commands

timer-hold retry

L2TP commands -- timer-hold retry

Use timer-hold retry to set the keepalive retry limit.

Use undo timer-hold retry to restore the default.

Syntax

timer-hold retry retries

undo timer-hold retry

Default

The keepalive retry limit is 5.

Views

Virtual PPP interface view

Predefined user roles

network-admin

mdc-admin

Parameters

retries: Specifies the maximum number of keepalive attempts in the range of 1 to 255.

Usage guidelines

A virtual PPP interface sends keepalive packets at keepalive intervals to detect the availability of the peer. If the interface fails to receive keepalive packets when the keepalive retry limit is reached, it determines that the link fails and reports a link layer down event.

To set the keepalive interval, use the timer-hold command.

On a slow link, increase the keepalive retry limit to prevent false shutdown of the interface. This situation might occur when keepalive packets are delayed because a large packet is being transmitted on the link.

Examples

# Set the keepalive retry limit to 10 for Virtual-PPP 10.

<Sysname> system-view

[Sysname] interface virtual-ppp 10

[Sysname-Virtual-PPP10] timer-hold retry 10

Related commands

timer-hold

L2TP commands -- tunnel authentication

Use tunnel authentication to enable L2TP tunnel authentication.

Use undo tunnel authentication to disable L2TP tunnel authentication.

Syntax

tunnel authentication

undo tunnel authentication

Default

L2TP tunnel authentication is enabled.

Views

L2TP group view

Predefined user roles

network-admin

mdc-admin

Usage guidelines

Tunnel authentication prevents the local end from establishing L2TP tunnels with illegal remote ends.

You can enable tunnel authentication on both sides or either side.

To ensure a successful tunnel establishment when tunnel authentication is enabled on both sides or either side, set the same non-null key on the LAC and the LNS. To set the tunnel authentication key, use the tunnel password command.

When neither side is enabled with tunnel authentication, the key settings of the LAC and the LNS do not affect the tunnel establishment.

For tunnel security, enable tunnel authentication.

Examples

# Enable L2TP tunnel authentication.

<Sysname> system-view

[Sysname] l2tp-group 1 mode lns

[Sysname-l2tp1] tunnel authentication

Related commands

tunnel password

L2TP commands -- tunnel avp-hidden

Use tunnel avp-hidden to enable transferring AVP data in hidden mode.

Use undo tunnel avp-hidden to restore the default.

Syntax

tunnel avp-hidden

undo tunnel avp-hidden

Default

AVP data is transferred over the tunnel in plaintext mode.

Views

L2TP group view

Predefined user roles

network-admin

mdc-admin

Usage guidelines

L2TP uses AVPs to transmit tunnel negotiation parameters, session negotiation parameters, and user authentication information. This feature can hide sensitive AVP data, such as user passwords. This feature encrypts AVP data with the key configured by using the tunnel password command before transmission.

The tunnel avp-hidden command can be configured for L2TP groups in both LAC and LNS modes. However, it does not take effect on L2TP groups in LNS mode.

For this command to take effect, you must enable tunnel authentication by using the tunnel authentication command.

Examples

# Enable transferring AVP data in hidden mode.

<Sysname> system-view

[Sysname] l2tp-group 1 mode lac

[Sysname-l2tp1] tunnel avp-hidden

Related commands

tunnel authentication

tunnel password

L2TP commands -- tunnel flow-control

Use tunnel flow-control to enable L2TP session flow control.

Use undo tunnel flow-control to disable L2TP session flow control.

Syntax

tunnel flow-control

undo tunnel flow-control

Default

L2TP session flow control is disabled.

Views

L2TP group view

Predefined user roles

network-admin

mdc-admin

Usage guidelines

This feature adds sequence numbers to transmitted packets and uses them to reorder packets arriving out of order and to detect lost packets.

This feature takes effect on both sent and received L2TP data messages. The L2TP sessions support this feature if either the LAC or LNS is enabled with this feature.

When the device acts as an LAC, a change in the flow control status on the LNS causes the same change in the flow control status of L2TP sessions. When the device acts as an LNS, a change in the flow control status on the LAC does not affect the flow control status of L2TP sessions.

Examples

# Enable L2TP session flow control.

<Sysname> system-view

[Sysname] l2tp-group 1 mode lac

[Sysname-l2tp1] tunnel flow-control

L2TP commands -- tunnel name

Use tunnel name to specify the local tunnel name.

Use undo tunnel name to restore the default.

Syntax

tunnel name name

undo tunnel name

Default

The local tunnel name is the device name. For more information about the device name, see Fundamentals Configuration Guide.

Views

L2TP group view

Predefined user roles

network-admin

mdc-admin

Parameters

name: Specifies the local tunnel name, a case-sensitive string of 1 to 31 characters.

Examples

# Specify the local tunnel name as itsme.

<Sysname> system-view

[Sysname] l2tp-group 1 mode lns

[Sysname-l2tp1] tunnel name itsme

Related commands

sysname (Fundamentals Command Reference)

L2TP commands -- tunnel password

Use tunnel password to configure the key for tunnel authentication.

Use undo tunnel password to restore the default.

Syntax

tunnel password { cipher | simple } string

undo tunnel password

Default

No key is configured for tunnel authentication.

Views

L2TP group view

Predefined user roles

network-admin

mdc-admin

Parameters

cipher: Specifies a password in encrypted form.

simple: Specifies a password in plaintext form. For security purposes, the password specified in plaintext form will be stored in encrypted form.

string: Specifies the password. Its plaintext form is a case-sensitive string of 1 to 16 characters. Its encrypted form is a case-sensitive string of 1 to 53 characters.

Usage guidelines

For this command to take effect, you must enable tunnel authentication by using the tunnel authentication command.

For the tunnel authentication key change to take effect, change the tunnel authentication key before tunnel negotiation is performed.

Examples

# Configure the key for tunnel authentication to a plaintext key yougotit.

<Sysname> system-view

[Sysname] l2tp-group 1 mode lac

[Sysname-l2tp1] tunnel password simple yougotit

Related commands

tunnel authentication

L2TP commands -- tunnel timer hello

Use tunnel timer hello to set the Hello interval.

Use undo tunnel timer hello to restore the default.

Syntax

tunnel timer hello hello-interval

undo tunnel timer hello

Default

The Hello interval is 60 seconds.

Views

L2TP group view

Predefined user roles

network-admin

mdc-admin

Parameters

hello-interval: Specifies the interval at which the LAC or the LNS sends Hello packets, in the range of 60 to 1000 seconds.

Usage guidelines

The device sends Hello packets at the set interval. This prevents the L2TP tunnels and sessions from being removed due to timeouts.

You can set different Hello intervals for the LNS and LAC.

Examples

# Set the Hello interval to 90 seconds.

<Sysname> system-view

[Sysname] l2tp-group 1 mode lac

[Sysname-l2tp1] tunnel timer hello 90

L2TP commands -- user

Use user to configure the condition for the LAC to initiate tunneling requests.

Use undo user to restore the default.

Syntax

user { domain domain-name | fullusername user-name }

undo user

Default

No condition is configured for the LAC to initiate tunneling requests.

Views

L2TP group view

Predefined user roles

network-admin

mdc-admin

Parameters

domain domain-name: Configures the LAC to initiate tunneling requests to the LNS when the domain name of a user matches a configured domain name. The domain-name argument represents the domain name of the user and is an case-insensitive string of 1 to 24 characters.

fullusername user-name: Configures the LAC to initiate tunneling requests to the LNS when the username of a user matches a configured full username. The domain-name argument represents the username of the user and is a case-sensitive string of 1 to 255 characters.

Usage guidelines

This command is available only on L2TP groups in LAC mode.

If you execute this command multiple times for an L2TP group, the most recent configuration takes effect.

Examples

# Configure the LAC to initiate tunneling requests to the LNS when the username of the user is test@aabbcc.net.

<Sysname> system-view

[Sysname] l2tp-group 1 mode lac

[Sysname-l2tp1] user fullusername test@aabbcc.net

L2TP commands -- vpn-instance

Use vpn-instance to assign a tunnel peer to a VPN.

Use undo vpn-instance to restore the default.

Syntax

vpn-instance vpn-instance-name

undo vpn-instance

Default

A tunnel peer belongs to the public network.

Views

L2TP group view

Predefined user roles

network-admin

mdc-admin

Parameters

vpn-instance-name: Specifies an MPLS L3VPN instance by its name, a case-sensitive string of 1 to 31 characters.

Usage guidelines

This command enables the device to transmit L2TP control messages and data messages in the specified VPN by searching the routing table in that VPN.

When one L2TP endpoint is in a VPN, assign the peer endpoint to the VPN for correct packet forwarding between the two endpoints.

The tunnel peer and the physical port connecting to the tunnel peer should belong to the same VPN. The VPN to which this physical port belongs is configured by using the ip binding vpn-instance command.

The specified VPN must already exist.

Examples

# Assign the tunnel peer to VPN vpn1.

<Sysname>system-view

[Sysname] l2tp-group 1 mode lac

[Sysname-l2tp1] vpn-instance vpn1

Related commands

ip vpn-instance (MPLS Command Reference)

ip binding vpn-instance (MPLS Command Reference)