set-dscp-outer

Function

The set-dscp-outer command configures the device to mark the outer DSCP value of the L2TP control packet so that the device and the peer device (LNS) can negotiate the AVP 47 attribute.

The undo set-dscp-outer command restores the default value of the outer DSCP value of the L2TP control packet.

By default, the DSCP value in the outer IP header of control packets sent by an LNS is determined by the AVP47/AVP48 attribute value configured on the LAC connecting to the LNS. If no AVP47/AVP48 attribute value is configured on the LAC, the default DSCP value is 48.

This command is supported only on the NetEngine 8000 F1A.

Format

set-dscp-outer [ lns ] dscp-value

undo set-dscp-outer

undo set-dscp-outer lns

Parameters

Parameter	Description	Value
lns	Specifies the peer device (LNS).	-
dscp-value	Specifies a DSCP value in the outer IP header of control packets sent by an LNS.	The value is an integer ranging from 0 to 63.

Parameter

Description

Value

lns

Specifies the peer device (LNS).

dscp-value

Specifies a DSCP value in the outer IP header of control packets sent by an LNS.

The value is an integer ranging from 0 to 63.

Views

L2TP group view

Default Level

2: Configuration level

Task Name and Operations

Task Name	Operations
l2tp	write

Usage Guidelines

Usage Scenario

After you run the set-dscp-outer command on the device, the device marks the DSCP value of the L2TP control packets used to establish the L2TP tunnel. The device then negotiates with the peer device (LNS) for AVP 47 attribute.

Packets with different DSCP values have different priorities. To view policies adopted for packets of different priorities, run the display diffserv domain command to view the mapping among the DSCP value, PHB, and color. On the LAC, the DiffServ domain is configured on the BAS interface.

For the L2TP control packets in which the AVP 47 attribute is negotiated, QoS mapping is not performed in the inbound direction of the tunnel.

Configuration Impact

After this command is run, when packets are sent to an MPLS network, the MPLS EXP and DSCP values are mapped. The DSCP value specified in the set-dscp-outer lns <dscp-value> command is first mapped to an internal priority based on the fixed mapping, and then the internal priority is mapped to an MPLS EXP value.

Precautions

In VS mode, this command is supported only on the admin VS.

This command takes effect only on the LAC.

After this command is run, the DSCP value carried in the AVP47/AVP48 attribute configured on a LAC no longer takes effect on an LNS connecting to the LAC.

The configuration takes effect only for users that go online through tunnels established after the command is run.

The set-dscp-outer command configures the device to mark the outer DSCP value of the L2TP control packet so that the device and the peer device (LNS) can negotiate the AVP 47 attribute.

During negotiation, if the DSCP value is mapped to a red queue, the LNS ignores the value and uses the fixed value 48.

Example

# Set the DSCP value in the outer IP header of control packets sent by an LNS to 55.

<HUAWEI> system-view
[~HUAWEI] l2tp-group huawei
[*HUAWEI-l2tp-huawei] set-dscp-outer lns 55

# Set the priority of the L2TP control packets to 20.

<HUAWEI> system-view
[~HUAWEI] l2tp-group group1
[*HUAWEI-l2tp-group1] set-dscp-outer 20