07-MPLS Command Reference

HomeSupportResource CenterH3C S6850 & S9850 Switch Series Command References-Release 655x-6W10107-MPLS Command Reference
01-Basic MPLS commands
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01-Basic MPLS commands 113.07 KB

Basic MPLS commands

display mpls forwarding ilm

Use display mpls forwarding ilm to display Incoming Label Map (ILM) entries.

Syntax

display mpls forwarding ilm [ label ] [ slot slot-number ]

Views

Any view

Predefined user roles

network-admin

network-operator

Parameters

label: Displays the ILM entry with the specified incoming label. The value range for this argument is 16 to 1048575. If you do not specify an incoming label, this command displays ILM entry information for all incoming labels.

slot slot-number: Specifies an IRF member device by its member ID. If you do not specify a member device, this command displays ILM entries for the master device.

Usage guidelines

An ILM entry records the label operation type, outgoing label, and other forwarding information.

After an LSR receives a labeled packet, it performs the following operations:

1.     Identifies the ILM entry that matches the top label of the packet.

2.     Performs the specified label operation.

3.     Forwards the packet.

Examples

# Display all ILM entries.

<Sysname> display mpls forwarding ilm

Total ILM entries: 3

 

Flags: T - Forwarded through a tunnel

       N - Forwarded through the outgoing interface to the nexthop IP address

       B - Backup forwarding information

       A - Active forwarding information

       M – P2MP forwarding information

 

InLabel Oper    VRF   Flag SwapLabel Forwarding Info

--------------------------------------------------------------------------------

30      SWAP    0     T    1000      1024

1279    POP     0     -    -         -

1407    SWAP    0     NA   1271      Vlan10                    50.2.0.2

                      NB   1270      Tun0                      0.0.0.0

Table 1 Command output

Field

Description

Total ILM entries

Total number of ILM entries.

InLabel

Incoming label.

Oper

Operation type:

·     POP—Pops the label.

·     POPGO—Pops the label and forwards the packet to another tunnel.

·     SWAP—Swaps the label.

VRF

Index of a VPN instance.

Flag

Forwarding flag:

·     T—Forwarded through a tunnel.

·     N—Forwarded through the outgoing interface to the next hop IP address.

·     B—Backup forwarding information.

·     A—Active forwarding information.

·     M—P2MP forwarding information. This flag is not supported in the current software version.

SwapLabel

Outgoing label value.

Forwarding Info

Forwarding information:

·     When the forwarding flag is N, the forwarding information records the outgoing interface and the next hop.

·     When the forwarding flag is T, the forwarding information records the NID.

display mpls forwarding nhlfe

Use display mpls forwarding nhlfe to display Next Hop Label Forwarding Entry (NHLFE) entries.

Syntax

display mpls forwarding nhlfe [ nid ] [ slot slot-number ]

Views

Any view

Predefined user roles

network-admin

network-operator

Parameters

nid: Displays the NHLFE entry with the specified NID. The NID value is in the range of 0 to 4294967294. If you do not specify an NID, this command displays NHLFE entry information for all NIDs.

slot slot-number: Specifies an IRF member device by its member ID. If you do not specify a member device, this command displays NHLFE entries for the master device.

Usage guidelines

An NHLFE entry records label forwarding information, such as the outgoing label and outgoing interface. NHLFE entries are mainly used to add multiple labels to packets.

To add multiple labels to a packet, an LSR performs the following operations:

1.     Obtains the bottom label and NID in the matching FIB or ILM entry.

2.     Obtains the outer label in the NHLFE entry identified by the NID.

Examples

# Display the NHLFE entry with NID 2048.

<Sysname> display mpls forwarding nhlfe 2048

Flags: T - Forwarded through a tunnel

       N - Forwarded through the outgoing interface to the nexthop IP address

       B - Backup forwarding information

       A - Active forwarding information

       M – P2MP forwarding information

 

NID        Tnl-Type Flag OutLabel Forwarding Info

--------------------------------------------------------------------------------

2048       LSP      NA   2025     Vlan10                    10.11.112.26

# Display all NHLFE entries.

<Sysname> display mpls forwarding nhlfe

Total NHLFE entries: 5

 

Flags: T - Forwarded through a tunnel

       N - Forwarded through the outgoing interface to the nexthop IP address

       B - Backup forwarding information

       A - Active forwarding information

       M – P2MP forwarding information

 

NID        Tnl-Type Flag OutLabel Forwarding Info

--------------------------------------------------------------------------------

10         -        TA   -        2049

20         -        TA   -        2050

2048       LSP      NA   2025     Vlan10                    10.11.112.26

2049       LSP      NA   3024     Vlan20                    10.11.112.26

                    TB   3026     20

2050       LSP      NA   3025     Vlan30                    10.11.113.26

Table 2 Command output

Field

Description

Total NHLFE entries

Total number of NHLFE entries.

NID

NHLFE entry index.

Tnl-Type

Tunnel type:

·     LOCAL—Direct LSP tunnel.

·     LSP—Static LSP tunnel, or LSP tunnel signaled using LDP or BGP.

·     CRLSP—Static CRLSP tunnel or CRLSP tunnel signaled using RSVP.

·     SRLSP—Static SRLSP tunnel.

·     - (a hyphen)—The tunnel type is invalid.

Flag

Forwarding flag:

·     T—Forwarded through a tunnel.

·     N—Forwarded through the outgoing interface to the next hop IP address.

·     B—Backup forwarding information.

·     A—Active forwarding information.

·     M—P2MP forwarding information.

OutLabel

Outgoing label.

Forwarding Info

Forwarding information:

·     When the forwarding flag is N, the forwarding information records the outgoing interface and the next hop.

·     When the forwarding flag is T, the forwarding information records the NID.

display mpls interface

Use display mpls interface to display MPLS interface information, including the interface name, interface status, and interface MPLS MTU.

Syntax

display mpls interface [ interface-type interface-number ]

Views

Any view

Predefined user roles

network-admin

network-operator

Parameters

interface-type interface-number: Specifies an interface by the interface type and number. If you do not specify an interface, this command displays MPLS information for all MPLS-enabled interfaces.

Examples

# Display all MPLS interfaces.

<Sysname> display mpls interface

Interface               Status       MPLS MTU

Vlan10                  Up           1500

Vlan20                  Up           1500

The MPLS MTU of an interface is in bytes.

Related commands

mpls enable

mpls mtu

display mpls label

Use display mpls label to display MPLS label usage information.

Syntax

display mpls label { label-value1 [ to label-value2 ] | all }

Views

Any view

Predefined user roles

network-admin

network-operator

Parameters

label-value1: Specifies a label value. The value range is 16 to 1048575. If used with the label-value2 argument, the label-value1 argument represents the start label of a label range.

to label-value2: Specifies the end label of the label range. The value range for the end label is 16 to 1048575. If you specify a label range by using the label-value1 argument and the to label-value2 option, this command displays usage information for the specified range of labels.

all: Specifies all labels.

Examples

# Display usage information for labels 1025 through 1027.

<Sysname> display mpls label 1025 to 1027

Label          Owner          State

1025           LDP            Alloc

1026           LDP            Alloc

1027           LDP            Inuse

Table 3 Command output

Field

Description

Label

Label value.

Owner

Protocol that is using the label:

·     Static—Static LSP.

·     LDP.

·     BGP.

·     StaticCR—Static CRLSP or static SRLSP.

·     RSVP.

·     L2VPN.

This field displays a hyphen (-) when the label state is Idle.

State

Usage state of the label:

·     Idle—The label is idle.

·     Alloc—The label has been allocated.

·     Pending—The label has been released but is still used by an LSP entry.

·     Inuse—The label has been allocated and used by an LSP entry.

display mpls lsp

Use display mpls lsp to display LSP information.

Syntax

display mpls lsp [ egress | in-label label-value | ingress | outgoing-interface interface-type interface-number | protocol { bgp | ldp | local | rsvp-te | static | static-cr } | transit ] [ vpn-instance vpn-instance-name ] [ ipv4-address mask-length | ipv6 [ ipv6-address prefix-length ] ] [ verbose ]

Views

Any view

Predefined user roles

network-admin

network-operator

Parameters

egress: Displays the LSPs taking the current LSR as egress.

in-label label-value: Displays the LSPs using the specified label as the incoming label, in the range of 0 to 1048575.

ingress: Displays the LSPs taking the current LSR as ingress.

outgoing-interface interface-type interface-number: Displays the LSPs using the specified interface as the outgoing interface. The interface-type interface-number argument specifies an interface by its type and number.

protocol: Displays the LSPs established by a protocol.

bgp: Displays BGP LSPs.

ldp: Displays LDP LSPs.

local: Displays the LSPs to the direct next hops or the LSPs that use the local MPLS TE tunnel interfaces as the LSP heads.

rsvp-te: Displays CRLSPs established by RSVP-TE.

static: Displays static LSPs.

static-cr: Displays static CRLSPs and static SRLSPs.

transit: Displays the LSPs taking the current LSR as a transit LSR.

vpn-instance vpn-instance-name: Displays LSPs for the specified MPLS L3VPN instance. The vpn-instance-name is a case-sensitive string of 1 to 31 characters. If you do not specify this option, the command displays LSPs for the public network.

ipv4-address mask-length: Displays the IPv4 LSP for an FEC specified by an IPv4 address and a mask length. The value range for the mask length is 0 to 32.

ipv6: Displays IPv6 LSP information. If you do not specify this keyword, the command displays IPv4 LSP information.

ipv6-address prefix-length: Displays the IPv6 LSP for an FEC specified by an IPv6 address and a prefix length. The value range for the prefix length is 0 to 128.

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

Usage guidelines

If you do not specify any parameters, this command displays brief information about all LSPs. If you specify only the verbose keyword, this command displays detailed information about all LSPs.

Examples

# Display brief information about all IPv4 LSPs.

<Sysname> display mpls lsp

FEC                         Proto    In/Out Label    Interface/Out NHLFE

100.100.100.100/24          LDP      -/1049          Vlan20

Backup                               -/1050          Vlan21

100.100.100.10/24           LDP      -/1051          Vlan22

Backup                               -/1050          Vlan21

100.100.100.10/24           LDP      -/1049          Vlan30

101.100.100.10/24           LDP      1026/1049       Vlan20

102.100.100.10/24           LDP      1027/-          -

103.100.100.10/24           LDP      1028/1049       Tunnel10

110.100.100.20/24           BGP      -/1049          Vlan20

111.100.100.10/24           BGP      2028/1049       Vlan20

112.100.100.10/24           BGP      2029/-          Vlan20

113.100.100.10/24           BGP      2030/1049       NHLFE1500

114.100.100.10/24           BGP      2031/1050       Tunnel100

100.100.100.100             Local    -/-             Vlan20

101.101.101.101/32          Static   -/100           Vlan20

-                           Static   100/200         Vlan20

-                           Static   101/-           Vlan20

Table 4 Command output

Field

Description

FEC

Forwarding equivalence class:

·     IP address/mask—Classifies FECs by destination address.

·     IP address—Classifies FECs by next hop.

·     IP address/Out Label—Classifies FECs by next hop and outgoing label.

·     Ingress LSR ID/Tunnel ID/LSP ID—RSVP TE FEC.

·     - (a hyphen)—The LSP is a static transit LSP, static egress LSP, adjacency path for static SRLSPs, static transit CRLSP, or static egress CRLSP.

·     Backup—The LSP is a backup LSP of the previous LSP.

Proto

Label distribution protocol:

·     LDP.

·     BGP.

·     RSVP.

·     Static.

·     StaticCR—Static CRLSP or static SRLSP.

·     Local—LSP to a direct next hop or LSP that uses a local MPLS TE tunnel interface as the LSP head.

In/Out Label

Incoming label/outgoing label.

Interface/Out NHLFE

Outgoing interface name or NHLFE entry index.

NHLFEnumber specifies the outer LSP that carries the current LSP. The outer LSP is that matches the NHLFE entry with an NID of number.

# Display IPv6 LSP information.

<Sysname> display mpls lsp ipv6

FEC      : 100:100:100:100:100:100:100:100/128

Protocol : BGP      In-Label     : 1200

Out-Label: 1300     Out-Interface: Vlan10

BkLabel  : 1400     BkInterface  : Vlan20

Table 5 Command output

Field

Description

FEC

Forwarding equivalence class:

·     IP address/mask—Classifies FECs by destination address.

·     IP address—Classifies FECs by next hop.

·     IP address/Out Label—Classifies FECs by next hop and outgoing label.

·     - (a hyphen)—The LSP is a static transit LSP or static egress LSP.

Protocol

Label distribution protocol:

·     LDP.

·     BGP.

·     Static.

·     Local—LSP to a direct next hop or LSP that uses a local MPLS TE tunnel interface as the LSP head.

BkLabel

Outgoing label of the backup LSP.

BkInterface

Outgoing interface of the backup LSP.

# Display detailed information about all LSPs.

<Sysname> display mpls lsp verbose

Destination  : 56.10.10.2

FEC          : 56.10.10.2/32

Protocol     : LDP

LSR Type     : Egress

Service      : -

In-Label     : 1024

State        : Active

 

Destination  : 56.10.10.4

FEC          : 56.10.10.2/32

Protocol     : LDP

LSR Type     : Transit

Service      : -

In-Label     : 1026

Path ID      : 0x40000000.1

State        : Active

Out-Label    : 1800

Nexthop      : 10.1.1.2

Out-Interface: Vlan10

BkLabel      : 1900

BkNexthop    : 20.1.1.2

BkInterface   : Vlan20

 

Destination  : 56.10.10.4

FEC          : 56.10.10.2/32

Protocol     : LDP

LSR Type     : Ingress

Service      : -      

NHLFE ID     : 2000

State        : Active

Out-Label    : 1800

Nexthop      : 10.1.1.2

Out-Interface: Vlan10

Table 6 Command output

Field

Description

Destination

LSP destination address.

FEC

Forwarding equivalence class:

·     IP address/mask—Classifies FECs by destination address.

·     IP address—Classifies FECs by next hop.

·     IP address/Out Label—Classifies FECs by next hop and outgoing label.

·     - (a hyphen)—The LSP is a static transit LSP or static egress LSP.

Protocol

Label distribution protocol:

·     LDP.

·     BGP (instance-name)—The instance-name specifies a BGP instance name. The value of default represents the default BGP instance.

·     Static.

·     Local—LSP to a direct next hop, or LSP that uses a local MPLS TE tunnel interface as the LSP head.

LSR Type

LSR type:

·     Ingress—The current LSR is the ingress node of the LSP.

·     Transit—The current LSR is a transit node of the LSP.

·     Egress—The current LSR is the egress node of the LSP.

Service

This field is not supported in the current software version.

Service deployed on the LSP.

Path ID

Forwarding path. The value is in the format of 0xnn.m. The nn represents the NHLFE group ID of the outer LSPs that carry the current LSP, and m represents the sequence number of the equivalence path.

NHLFE ID

NHLFE entry index.

State

LSP state:

·     Active—The LSP is in use.

·     Inactive—The LSP is idle.

BkLabel

Outgoing label of the backup LSP.

BkNexthop

Next hop address of the backup LSP.

BkInterface

Outgoing interface of the backup LSP.

display mpls nib

Use display mpls nib to display MPLS Nexthop Information Base (NIB) information.

Syntax

display mpls nib [ nib-id ]

Views

Any view

Predefined user roles

network-admin

network-operator

Parameters

nib-id: Specifies a next hop ID in the range of 1 to FFFFFFFFFFFFFFFE. If you do not specify a next hop, this command displays information about all MPLS next hops.

Examples

# Display information about all MPLS next hops.

<Sysname> display mpls nib

NIB ID: 0x40000000

  Users: 1

  Status: Active

  ECMP number: 1

      Outgoing NHLFE ID: 1024

      Backup outgoing NHLFE ID: 1027

Table 7 Command output

Field

Description

NIB ID

ID of the next hop.

Users

Number of ILM entries that use this next hop.

Status

Next hop status:

·     Active—The next hop is active.

·     Dummy—The next hop is inactive.

ECMP number

Number of equal-cost NHLFE entries.

Outgoing NHLFE ID

ID of the NHLFE entry to which the next hop corresponds.

Backup outgoing NHLFE ID

ID of the backup NHLFE entry.

display mpls nid

Use display mpls nid to display usage information for NIDs.

Syntax

display mpls nid [ nid-value1 [ to nid-value2 ] ]

Views

Any view

Predefined user roles

network-admin

network-operator

Parameters

nid-value1: Specifies an NID. The value range is 0 to 65535. If used with the nid-value2 argument, the nid-value1 argument represents the start NID of an NID range.

to nid-value2: Specifies the end NID of the NID range. The value range for the end NID is 0 to 65535. If you specify an NID range by using the nid-value1 argument and the to nid-value2 option, this command displays usage information for the specified range of NIDs.

Usage guidelines

NIDs are 32-bit binary numbers. They include fixed NIDs and dynamic NIDs.

·     Fixed NIDs—Generated for tunnel interfaces. The highest four bits are a value other than 0000.

·     Dynamic NIDs—NIDs except fixed NIDs. The highest four bits are 0s.

This command displays usage information only for dynamic NIDs.

If you do not specify any parameters, this command displays usage information for all dynamic NIDs.

Examples

# Display usage information for dynamic NIDs 1028 through 1500.

<Sysname> display mpls nid 1028 to 1500

NID alloc state: '.' means not used, '$' means used

1028   :...$.... ........ ........ ........  ........ ........ ........ ........

1092   :........ ........ ........ ........  ........ ........ ........ ........

1156   :........ ........ ........ ........  ........ ........ ........ ........

1220   :........ ........ ........ ........  ........ ........ ........ ........

1284   :........ ........ ........ ........  ........ ........ ........ ........

1348   :........ ........ ........ ........  ........ ........ ........ ........

1412   :........ ........ ........ ........  ........ ........ ........ ........

1476   :........ ........ ........ .

display mpls summary

Use display mpls summary to display MPLS summary information.

Syntax

display mpls summary

Views

Any view

Predefined user roles

network-admin

network-operator

Examples

# Display MPLS summary information.

<Sysname> display mpls summary

MPLS LSR ID      : 1.1.1.1

Egress Label Type: Implicit-null

Labels:

  Range                                  Idle

  16-15999                               15983

  16000-24000                            8001

  24001-88888                            64888

Protocols:

  Type                                   State

  Static                                 Normal

  CCC                                    Normal

  StaticCR                               Normal

  Local                                  Normal                                

Table 8 Command output

Field

Description

Egress Label Type

Label type that the egress node assigns to the penultimate hop:

·     Implicit-null.

·     Explicit-null.

·     Non-null.

Labels

Label information.

Range

Label range.

Idle

Number of idle labels in the label range.

Protocols

Label distribution protocols that generated LSPs and their running states.

Type

Protocol type:

·     LDP.

·     BGP (instance-name). The instance-name specifies a BGP instance name. The value of default represents the default BGP instance.

·     RSVP.

·     Static—Static LSP.

·     StaticCR—Static CRLSP.

·     TE.

·     CCC. This protocol is not supported in the current software version.

State

Label distribution protocol running state:

·     Normal—The protocol is in normal state.

·     Recover—The protocol is in the GR process.

mpls enable

Use mpls enable to enable MPLS on an interface.

Use undo mpls enable to disable MPLS on an interface.

Syntax

mpls enable

undo mpls enable

Default

MPLS is disabled on an interface.

Views

Interface view

Predefined user roles

network-admin

Examples

# Enable MPLS on VLAN-interface 2.

<Sysname> System-view

[Sysname] interface vlan-interface 2

[Sysname-Vlan-interface2] mpls enable

Related commands

display mpls interface

mpls label advertise

Use mpls label advertise to specify the type of label the egress node will advertise to the penultimate hop.

Use undo mpls label advertise to restore the default.

Syntax

mpls label advertise { explicit-null | implicit-null | non-null }

undo mpls label advertise

Default

As egress, the device advertises an implicit null label to the penultimate hop.

Views

System view

Predefined user roles

network-admin

Parameters

explicit-null: Specifies the egress node to advertise an explicit null label of 0 to the penultimate hop.

implicit-null: Specifies the egress node to advertise an implicit null label of 3 to the penultimate hop.

non-null: Specifies the egress node to advertise a non-null label to the penultimate hop.

Usage guidelines

As a best practice, configure the egress node to advertise an implicit null label to the penultimate hop if the penultimate hop supports PHP.

If you want to simplify packet forwarding on egress but keep labels to determine QoS policies, configure the egress node to advertise an explicit null label to the penultimate hop.

Use non-null labels only in particular scenarios. For example, when OAM is configured on the egress node, the egress node can get the OAM function entity status only through non-null labels.

As a penultimate hop, the device accepts the implicit null label, explicit null label, or non-null label advertised by the egress node.

For LDP LSPs, the mpls label advertise command triggers LDP to delete the LSPs established before the command is executed and re-establishes new LSPs.

For BGP LSPs, the mpls label advertise command takes effect only on the BGP LSPs established after the command is executed. To apply the new setting to BGP LSPs established before the command is executed, delete the routes corresponding to the BGP LSPs, and then redistribute the routes.

Examples

# Configure the egress node to advertise an implicit null label to the penultimate hop.

<Sysname> system-view

[Sysname] mpls label advertise implicit-null

Related commands

reset mpls ldp

mpls lsr-id

Use mpls lsr-id to configure an LSR ID for the local LSR.

Use undo mpls lsr-id to restore the default.

Syntax

mpls lsr-id lsr-id

undo mpls lsr-id

Default

An LSR has no LSR ID.

Views

System view

Predefined user roles

network-admin

Parameters

lsr-id: Specifies an ID for identifying the LSR, in dotted decimal notation.

Usage guidelines

As a best practice, use the address of a loopback interface on the LSR as the LSR ID.

Examples

# Configure the LSR ID as 3.3.3.3 for the local node.

<Sysname> system-view

[Sysname] mpls lsr-id 3.3.3.3

Related commands

lsr-id

mpls mtu

Use mpls mtu to set the MPLS MTU for an interface.

Use undo mpls mtu to restore the default.

Syntax

mpls mtu size

undo mpls mtu

Default

The MPLS MTU of an interface is not configured. Fragmentation for MPLS packets is based on the IP MTU. If IP MTU is not configured, fragmentation for MPLS packets is based on the MTU of the interface. The length of a fragment does not include that of the MPLS label. Thus, after an MPLS label is added into a fragment, the length of the MPLS fragment might exceed the interface MTU.

Views

Interface view

Predefined user roles

network-admin

Parameters

size: Specifies the MPLS MTU of the interface, in the range of 46 to 65535 bytes.

Usage guidelines

This command is effective only when MPLS is enabled on the interface.

If the MPLS MTU is larger than the interface MTU, data forwarding might fail.

MPLS TE tunnel interfaces do not support this command.

Examples

# Set the MPLS MTU of VLAN-interface 2 to 1000 bytes.

<Sysname> system-view

[Sysname] interface vlan-interface 2

[Sysname-Vlan-interface2] mpls enable

[Sysname-Vlan-interface2] mpls mtu 1000

Related commands

display mpls interface

mpls ttl expiration enable

Use mpls ttl expiration enable to enable sending MPLS TTL-expired messages.

Use undo mpls ttl expiration enable to disable sending MPLS TTL-expired messages.

Syntax

mpls ttl expiration enable

undo mpls ttl expiration enable

Default

The MPLS TTL-expired messages sending feature is enabled.

Views

System view

Predefined user roles

network-admin

Usage guidelines

This command enables an LSR to generate an ICMP TTL-expired message upon receiving an MPLS packet with TTL being 1.

·     If the MPLS packet has only one label, the LSR sends the ICMP TTL-expired message back to the source through IP routing.

·     If the MPLS packet has multiple labels, the LSR forwards the ICMP TTL-expired message along the LSP of the MPLS packet to the egress node. Then, the egress node sends the message back to the source.

Examples

# Disable sending MPLS TTL-expired messages.

<Sysname> system-view

[Sysname] undo mpls ttl expiration enable

mpls ttl propagate

Use mpls ttl propagate to enable TTL propagation.

Use undo mpls ttl propagate to disable TTL propagation.

Syntax

mpls ttl propagate { public | vpn }

undo mpls ttl propagate { public | vpn }

Default

TTL propagation is enabled for public network packets and is disabled for VPN packets.

Views

System view

Predefined user roles

network-admin

Parameters

public: Specifies public network packets.

vpn: Specifies VPN packets.

Usage guidelines

When TTL propagation is enabled, MPLS performs the following operations:

·     Copies the IP TTL to the label TTL for packets entering the MPLS network.

·     Copies the label TTL to the IP TTL for packets leaving the MPLS network.

If you enable TTL propagation on both ingress and egress, the IP tracert facility can show the real path in the MPLS network.

When TTL propagation is disabled, MPLS performs the following operations:

·     Sets the label TTL to 255 for packets entering the MPLS network.

·     Pops the label for packets leaving the MPLS network, without copying the label TTL value to the IP TTL.

The IP tracert facility cannot show the real path in the MPLS network.

Within an MPLS network, TTL is always copied between the labels of an MPLS packet. The mpls ttl propagate command affects only the propagation between IP TTL and label TTL.

As a best practice, set the same TTL processing mode on all LSRs of an LSP.

To enable TTL propagation for a VPN, you must enable it on all PE devices in the VPN. This allows you to obtain the same traceroute result (hop count) from those PEs.

Examples

# Enable TTL propagation for VPN packets.

<Sysname> system-view

[Sysname] mpls ttl propagate vpn

snmp-agent trap enable mpls

Use snmp-agent trap enable mpls to enable SNMP notifications for MPLS.

Use undo snmp-agent trap enable mpls to disable SNMP notifications for MPLS.

Syntax

snmp-agent trap enable mpls

undo snmp-agent trap enable mpls

Default

SNMP notifications for MPLS are disabled.

Views

System view

Predefined user roles

network-admin

Usage guidelines

To report critical MPLS events to an NMS, enable SNMP notifications for MPLS. For MPLS event notifications to be sent correctly, you must also configure SNMP on the device. For more information about SNMP configuration, see the network management and monitoring configuration guide for the device.

Examples

# Enable SNMP notifications for MPLS.

<Sysname> system-view

[Sysname] snmp-agent trap enable mpls