prefix-list prefix-list-name: Automatically establishes targeted LDP sessions on receiving Targeted Hellos from peers permitted by an IPv4 prefix list. The prefix-list-name argument represents the IPv4 prefix list name, a case-sensitive string of 1 to 63 characters.

Usage guidelines

In some networks, the destination device must be able to establish an targeted LDP session automatically when it receives Targeted Hellos from the source device. For example, on a remote LFA FRR network, the source node computes PQ nodes. LDP needs to automatically establish targeted sessions between the source node and the PQ nodes. To achieve this purpose, you must execute this command on the PQ nodes. Then, the PQ nodes can automatically establish the targeted LDP sessions on receiving Targeted Hellos from the source node. For more information about remote LFA FRR, see IS-IS configuration in Layer 3—IP Routing Configuration Guide.

If you execute this command multiple times, the most recent configuration takes effect.

Examples

# Configure the device to automatically establish targeted LDP sessions when it receives Targeted Hellos from peers 1.1.1.9 and 2.2.2.9.

<Sysname> system-view

[Sysname] ip prefix-list accept-fec-list index 1 permit 1.1.1.9 32

[Sysname] ip prefix-list accept-fec-list index 2 permit 2.2.2.9 32

[Sysname] mpls ldp

[Sysname-ldp] accept target-hello prefix-list accept-fec-list

Related commands

ip prefix-list (Layer 3—IP Routing Command Reference)

backoff

Use backoff to set the LDP backoff initial delay time and maximum delay time.

Use undo backoff to restore the default.

Syntax

backoff initial initial-time maximum maximum-time

undo backoff

Default

The LDP backoff initial delay time is 15 seconds, and the maximum delay time is 120 seconds.

Views

LDP view

LDP-VPN instance view

Predefined user roles

network-admin

Parameters

initial initial-time: Specifies the LDP backoff initial delay time in the range of 15 to 50331 seconds.

maximum maximum-time: Specifies the LDP backoff maximum delay time in the range of 120 to 50331 seconds.

Usage guidelines

LDP peers continually negotiate with each other until a session is set up. If LDP peers use incompatible negotiation parameters (for example, different label advertisement modes), a large amount of negotiation traffic will enter the network. To suppress LDP session negotiation traffic, use this command to control the interval between negotiation attempts.

After LDP fails to establish a session to a peer LSR for the first time, LDP does not start another attempt until the initial delay timer expires. If the session setup fails again, LDP waits for two times the previous delay before the next attempt. This process continues until the maximum delay time is reached. After that, the maximum delay time always takes effect.

If you configure the initial delay time to be larger than the maximum delay time, the configuration does not take effect. LDP uses the maximum delay time as the initial delay time.

Examples

# Configure LDP backoff for the public network, and set the initial delay time to 100 seconds and the maximum delay time to 300 seconds.

<Sysname> system-view

[Sysname] mpls ldp

[Sysname-ldp] backoff initial 100 maximum 300

display mpls ldp discovery

Use display mpls ldp discovery to display LDP discovery information.

Syntax

display mpls ldp discovery [ vpn-instance vpn-instance-name ] [ interface interface-type interface-number | peer peer-lsr-id | targeted-peer ipv4-address ] [ verbose ]

Views

Any view

Predefined user roles

network-admin

network-operator

Parameters

vpn-instance vpn-instance-name: Displays LDP discovery information for the specified MPLS L3VPN instance. The vpn-instance-name argument represents the VPN instance name, a case-sensitive string of 1 to 31 characters. If you do not specify a VPN instance, this command displays LDP discovery information for the public network.

interface interface-type interface-number: Displays information about basic discovery that uses the specified interface to send Link Hellos. The interface-type interface-number argument represents the interface type and number.

peer peer-lsr-id: Displays information about both basic and extended discovery mechanisms that have discovered the specified LDP peer. The peer-lsr-id argument represents the LSR ID of the LDP peer.

targeted-peer: Displays information about extended discovery that has sent Targeted Hellos to the specified LDP peer.

ipv4-address: Specifies the IPv4 address of the LDP peer.

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

Usage guidelines

If you do not specify the interface, peer, or targeted-peer keyword, this command displays all LDP IPv4 basic and extended discovery information.

Examples

# Display brief LDP IPv4 discovery information for the public network.

<Sysname> display mpls ldp discovery

Type: L - Link Hello, T - Targeted Hello

Discovery Source Hello Sent/Rcvd Peer LDP ID

(L) Vlan10 83/80 100.100.100.18:0

200.100.100.18:0

(T) 100.100.100.18 23/20 100.100.100.18:0

Table 1 Command output

Field	Description
Type	Type of LDP discovery: · L—Basic discovery, which sends Link Hellos to discover peers. · T—Extended discovery, which sends Targeted Hellos to discover peers.
Discovery Source	Discovery source. · If the LDP discovery type is L, this field displays the interface that discovers the peer. · If the LDP discovery type is T, this field displays the IPv4 address of the peer.
Hello Sent/Rcvd	Number of hellos sent to the peer/number of hellos received from the peer.
Peer LDP ID	LDP identifier of the LDP peer.

# Display detailed LDP IPv4 discovery information for the public network.

<Sysname> display mpls ldp discovery verbose

Link Hellos:

Interface Vlan-interface10

Hello Interval : 5000 ms Hello Sent/Rcvd : 83/160

Transport Address: 100.100.100.17

Peer LDP ID : 100.100.100.18:0

Source Address : 202.118.224.18 Transport Address: 100.100.100.18

Hello Hold Time: 15 sec (Local: 15 sec, Peer: 15 sec)

Peer LDP ID : 100.100.100.20:0

Source Address : 202.118.224.20 Transport Address: 100.100.100.20

Hello Hold Time: 15 sec (Local: 15 sec, Peer: 15 sec)

Targeted Hellos:

100.100.100.17 -> 100.100.100.18 (Active, Passive)

Hello Interval : 15000 ms Hello Sent/Rcvd : 23/20

Transport Address: 100.100.100.17

Session Setup : Config/Tunnel

Peer LDP ID : 100.100.100.18:0

Source Address : 100.100.100.18 Transport Address: 100.100.100.18

Hello Hold Time: 45 sec (Local: 45 sec, Peer: 45 sec)

100.100.100.17 -> 100.100.100.20 (Active, Passive)

Hello Interval : 15000 ms Hello Sent/Rcvd : 23/22

Transport Address: 100.100.100.17

Session Setup : Config/Tunnel

Peer LDP ID : 100.100.100.20:0

Source Address : 100.100.100.20 Transport Address: 100.100.100.20

Hello Hold Time: 45 sec (Local: 45 sec, Peer: 45 sec)

Table 2 Command output

Field	Description
Link Hellos	Information about basic discovery that sends Link Hellos on interfaces. In a non-point-to-point network, an interface might discover multiple peers.
Interface	Interface using basic discovery.
Hello Interval	Hello interval in milliseconds.
Hello Sent/Rcvd	Number of Hellos sent or received on the interface.
Transport Address	Local transport address.
Session Setup	Targeted LDP session setup mode. Possible values include: · Config—The session was triggered by user configuration. · L2VPN—The session was triggered automatically by MPLS L2VPN. · Session-Protect—The session was triggered by the session protection feature. · OSPF RLFA—The session was triggered by OSPF Remote LFA. · IS-IS RLFA—The session was triggered by IS-IS Remote LFA. · Auto Accept—The session was triggered automatically on receiving a Targeted Hello.
Peer LDP ID	LDP identifier of the LDP peer.
Source Address	Source IP address of received Hello messages.
Destination Address	Destination IP address of received Hello messages.
Transport Address	Transport address in the received Hello messages—the transport address of the LDP peer.
Hello Hold Time	Hello hold time in seconds. · Local—Local hello hold time. · Peer—Peer hello hold time. The negotiated hello hold time is the smaller value of the local and peer hold time values.
Targeted Hellos	Information about extended LDP discovery that sends Targeted Hellos to peers.
100.100.100.17 -> 100.100.100.18 (Active, Passive)	· The address before -> (100.100.100.17 in this example) is the local IP address. · The address after -> (100.100.100.18 in this example) is the peer IP address. · (Active) indicates that the local LSR is the Targeted Hello sender. · (Passive) indicates that the local LSR is the Targeted Hello receiver. · (Active, Passive) indicates that the local LSR is both the Targeted Hello sender and receiver.

display mpls ldp fec

Use display mpls ldp fec to display LDP FEC-label mappings.

Syntax

display mpls ldp fec [ vpn-instance vpn-instance-name ] [ ipv4-address mask-length | summary ]

Views

Any view

Predefined user roles

network-admin

network-operator

Parameters

vpn-instance vpn-instance-name: Specifies an MPLS L3VPN instance by its name, a case-sensitive string of 1 to 31 characters. This command displays FEC-label mappings for the specified VPN instance. If you do not specify a VPN instance, this command displays FEC-label mappings for the public network.

ipv4-address mask-length: Specifies an IPv4 FEC by an IPv4 address and a mask length in the range of 0 to 32.

summary: Displays summary information about all FEC-label mappings learned by LDP.

Usage guidelines

If you specify only the summary keyword, this command displays summary information about all IPv4 FEC-label mappings.

If you do not specify the ipv4-address mask-length and summary parameters, this command displays detailed information about all IPv4 FEC-label mappings.

Examples

# Display detailed information about all IPv4 FEC-label mappings learned by LDP for the public network.

<Sysname> display mpls ldp fec

FEC: 100.100.100.18/32

Flags: 0x02

In Label: 1531

Label Advertisement Policy:

FEC Prefix-list: Fec-prefix-list

Peer Prefix-list: Peer-prefix-list

Upstream Info:

Peer: 100.100.100.18:0 State: Established (stale)

Peer: 100.100.100.20:0 State: Established (stale)

Downstream Info:

Peer: 100.100.100.18:0

Out Label: 3 State: Established (stale)

Next Hops: 202.118.224.18 Vlan10

100.19.100.18 Vlan20

Peer: 100.100.100.20:0

Out Label: 1025 State: Established (stale)

Label Stack Index: 16777218

FEC: 200.100.100.18/32 (No route)

Flags: 0x0

In Label: 1532

Upstream Info:

Peer: 200.200.200.28:0 State: Established

Downstream Info:

Peer: 120.100.100.18:0

Out Label: 3 State: Idle

Table 3 Command output

Field	Description
FEC	Forwarding equivalence class identified by an IP prefix.
Flags	FEC flag. It represents different things by setting different bits to 1. If multiple bits are set to 1, the flag represents all the things that correspond to those bits. This field displays the sum of the flag values. For example, if the FEC flag has values 0x00000001 and 0x00000020, this field displays 0x00000021. Possible value of the FEC flag: · 0x0—Initial value. · 0x00000001—Egress LSP. · 0x00000002—Ingress LSP. · 0x00000004—Waiting to add an outgoing label to RIB. · 0x00000008—Waiting to refresh LSPs in LSM. · 0x00000010—Ready to advertise labels. · 0x00000020—FEC-label mappings have been refreshed during a GR process. · 0x00000040—Delayed refreshing LSPs in LSM. · 0x00000080—Non-egress LSP waiting for the recovery during a GR process. · 0x20000000—PQ address registered by IS-IS Remote LFA.
In Label	Incoming label assigned by the local LSR to the FEC.
Label Advertisement Policy	Label advertisement policy.
FEC Prefix-list	IP prefix list for filtering FEC prefixes.
Peer Prefix-list	IP prefix list for filtering LDP peers.
Upstream Info	Upstream peer to which the local LSR advertised the FEC-label mapping and current state of the LSP.
Peer	LDP ID of an upstream peer.
State	Current state of the LSP established with the upstream peer: · Established—Active state. · Idle—Initial state. · Release Awaited—Waiting for a Release message. · Resource Awaited—Waiting for a label for the FEC. If the state is marked as stale, the FEC-label mapping is under a GR process.
Downstream Info	Downstream peer from which the local LSR received the FEC-label mapping, and current state of the LSP.
Peer	LDP ID of a downstream peer.
Out Label	Outgoing label assigned by the downstream LSR for the FEC.
State	Current state of the LSP established with the downstream peer: · Established—Active state. · Idle—Inactive state. If the state is marked as stale, the FEC-label mapping is under a GR process.
Next Hops	Next hops and outgoing interfaces.
Label Stack Index	Label stack index for the ingress LDP LSP selected for the current LDP LSP after route recursion.

# Display summary information about all IPv4 FEC-label mappings learned by LDP for the public network.

<Sysname> display mpls ldp fec summary

FECs : 3

Implicit Null: 1

Explicit Null: 0

Non-Null : 2

No Label : 0

No Route : 0

Sent : 3

Received : 3

Table 4 Command output

Field	Description
FECs	Number of FECs that LDP has discovered from the routing protocol or FEC-label mappings advertised by peers.
Implicit Null	Number of FECs that are bound to the implicit null label.
Explicit Null	Number of FECs that are bound to the explicit null label.
Non-Null	Number of FECs that are bound to non-null labels.
No Label	Number of FECs without a label.
No Route	Number of FECs without matching routes. The reason why an FEC has no matching route might be one of the following: · No matching route exists in the routing table. · The matching route exists in the routing table, but it is not redistributed into LDP.
Sent	Number of label mappings sent and being sent.
Received	Number of label mappings accepted.

display mpls ldp interface

Use display mpls ldp interface to display LDP interface information.

Syntax

display mpls ldp interface [ vpn-instance vpn-instance-name ] [ interface-type interface-number ]

Views

Any view

Predefined user roles

network-admin

network-operator

Parameters

vpn-instance vpn-instance-name: Specifies an MPLS L3VPN instance by its name, a case-sensitive string of 1 to 31 characters. This command displays LDP interface information for the specified VPN instance. If you do not specify a VPN instance, this command displays LDP interface information for the public network.

interface-type interface-number: Specifies an interface by its type and number. If you do not specify an interface, this command displays information about all LDP interfaces.

Examples

# Display information about all interfaces enabled with IPv4 LDP for the public network.

<Sysname> display mpls ldp interface

Interface MPLS LDP Auto-config

Vlan10 Enabled Configured -

Vlan20 Enabled Configured -

Table 5 Command output

Field	Description
Interface	Interface enabled with LDP.
MPLS	Whether the interface is enabled with MPLS.
LDP	Whether the interface is configured with the mpls ldp enable command.
Auto-config	This field is not supported in the current software version. LDP automatic configuration information: · If LDP autoconfiguration is enabled, this field displays IGP process information, such as OSPF process ID and OSPF area ID. · If LDP autoconfiguration is disabled, this field displays a hyphen (-).

Related commands

mpls ldp

mpls ldp enable

display mpls ldp lsp

Use display mpls ldp lsp to display information about LSPs generated by LDP.

Syntax

display mpls ldp lsp [ vpn-instance vpn-instance-name ] [ ipv4-address mask-length ]

Views

Any view

Predefined user roles

network-admin

network-operator

Parameters

vpn-instance vpn-instance-name: Specifies an MPLS L3VPN instance by its name, a case-sensitive string of 1 to 31 characters. This command displays LDP LSP information for the specified VPN instance. If you do not specify a VPN instance, this command displays LDP LSP information for the public network.

ipv4-address mask-length: Specifies an IPv4 FEC by an IPv4 address and a mask length in the range of 0 to 32.

Usage guidelines

If you do not specify the ipv4-address mask-length argument, this command displays information about LDP LSPs for all IPv4 FECs.

Examples

# Display LDP LSP information for IPv4 FECs on the public network.

<Sysname> display mpls ldp lsp

Status Flags: * - stale, L - liberal, B - backup, N/A – unavailable

FECs: 4 Ingress: 1 Transit: 1 Egress: 3

FEC In/Out Label Nexthop OutInterface/LSINDEX

1.1.1.1/32 -/3 10.1.1.1 Vlan10

1151/3 10.1.1.1 Vlan10

-/1025(B) 30.1.1.1 Vlan20

1151/1025(B) 30.1.1.1 Vlan20

2.2.2.2/32 3/-

-/1151(L)

10.1.1.0/24 1149/-

-/1149(L)

192.168.1.0/24 1150/-

-/1150(L)

Table 6 Command output

Field	Description
Status Flags	LSP status: · *—Stale, indicating that the LSP is under a GR process. · L—Liberal, indicating that the LSP is not activated because the peer that advertised the label is not the next hop of the route. · B—Backup, indicating a backup LSP. · N/A—Unavailable, indicating that the LSP is not the optimal LSP for traffic forwarding.
FECs	Total number of FECs.
Ingress	Number of LSPs that take the local device as the ingress node.
Transit	Number of LSPs that take the local device as a transit node.
Egress	Number of LSPs that take the local device as the egress node.
FEC	Forwarding equivalence class identified by an IP prefix.
In/Out Label	Incoming/outgoing label.
Nexthop	Next hop address for the FEC.
OutInterface/LSINDEX	Outgoing interface for the FEC or the label stack index of the LDP LSP. LSINDEXnumber specifies the ingress LDP LSP selected for the current LDP LSP after route recursion. The ingress LDP LSP is the one that matches the LSINDEX entry with a label stack index of number.

Related commands

display mpls forwarding nhlfe

display mpls lsp

display mpls ldp parameter

Use display mpls ldp parameter to display LDP running parameters.

Syntax

display mpls ldp parameter [ vpn-instance vpn-instance-name ]

Views

Any view

Predefined user roles

network-admin

network-operator

Parameters

vpn-instance vpn-instance-name: Specifies an MPLS L3VPN instance by its name, a case-sensitive string of 1 to 31 characters. This command displays LDP running parameters for the specified VPN instance. If you do not specify a VPN instance, this command displays LDP running parameters for the public network.

Usage guidelines

This command displays the following LDP running parameters:

· Global parameters, which are applicable to all LDP networks.

· Instance parameters, which are applicable to a specific LDP network.

Examples

# Display LDP running parameters for the public network.

<Sysname> display mpls ldp parameter

Global Parameters:

Protocol Version : V1 IGP Sync Delay on Restart : 90 sec

Nonstop Routing : Off Nonstop Routing State : Not Ready

Graceful Restart : Off Forwarding State Hold Time: 360 sec

Reconnect Time : 120 sec DSCP Value : 48

Instance Parameters:

Instance ID : 0

LSR ID : 1.1.1.1

Loop Detection : Off

Hop Count Limit : 32 Path Vector Limit : 32

Label Retention Mode: Liberal Label Distribution Control Mode: Ordered

IGP Sync Delay : 0 sec

Table 7 Command output

Field	Description
Global Parameters	LDP running parameters for all LDP-enabled networks.
Protocol Version	LDP protocol version.
IGP Sync Delay on Restart	Maximum delay time (in seconds) that LDP must wait before it notifies IGP of an LDP session-up event when there is an LDP restart.
Nonstop Routing	Whether the nonstop routing feature is enabled: · On—Enabled. · Off—Disabled.
Nonstop Routing State	LDP NSR state: · Ready—NSR is enabled, and LDP session and LSP information has been synchronized to the standby process. If an active/standby switchover occurs, the LDP session stays in Operational state, and the forwarding is not interrupted. · Not Ready—NSR is not enabled, or NSR is enabled but LDP session and LSP information synchronization to the standby process is not completed. If an active/standby switchover occurs, the LDP session might not be able to stay in Operational state, and the forwarding might be interrupted.
Graceful Restart	Whether the GR feature is enabled: · On—Enabled. · Off—Disabled.
Forwarding State Hold Time	MPLS Forwarding State Holding time in seconds.
Reconnect Time	Reconnect time in seconds.
DSCP Value	DSCP value for outgoing LDP packets.
Instance Parameters	LDP running parameters for a VPN instance or public network.
Instance ID	VPN instance ID. For the public network, this field displays 0.
LSR ID	LSR ID of the local device.
Loop Detection	Whether loop detection is enabled: · On—Enabled. · Off—Disabled.
Hop Count Limit	Hop count limit specified for loop detection.
Path Vector Limit	Path Vector length limit specified for loop detection.
Label Retention Mode	The device supports only the Liberal mode.
Label Distribution Control Mode	Label distribution control mode: Ordered or Independent.
IGP Sync Delay	Delay time (in seconds) that LDP must wait before it notifies IGP of an LDP session-up event.

display mpls ldp peer

Use display mpls ldp peer to display LDP peer and session information.

Syntax

display mpls ldp peer [ vpn-instance vpn-instance-name ] [ peer-lsr-id ] [ verbose ]

Views

Any view

Predefined user roles

network-admin

network-operator

Parameters

vpn-instance vpn-instance-name: Specifies an MPLS L3VPN instance by its name, a case-sensitive string of 1 to 31 characters. This command displays LDP peer and session information for the specified VPN instance. If you do not specify a VPN instance, this command displays LDP peer and session information for the public network.

peer peer-lsr-id: Specifies an LDP peer by its LSR ID. If you do not specify this option, the command displays all LDP peers and related session information.

verbose: Displays detailed LDP peer and session information. If you do not specify this keyword, the command displays brief LDP peer and session information.

Examples

# Display brief information about all LDP peers and LDP sessions for the public network.

<Sysname> display mpls ldp peer

Total number of peers: 1

Peer LDP ID State Role GR MD5 KA Sent/Rcvd

2.2.2.9:0 Operational Passive Off Off 39/39

Table 8 Command output

Field	Description
Peer LDP ID	LDP identifier of the peer.
State	State of the LDP session between the local LSR and the peer: · Non Existent—No TCP connection is established. · Initialized—A TCP connection has been established. · OpenRecv—LDP has received an acceptable initialization message. · OpenSent—LDP has sent an initialization message. · Operational—An LDP session has been established.
Role	Role of the local LSR in the session: Active or Passive. In a session, the LSR with a higher IP address takes the Active role. The Active LSR initiates a TCP connection to the passive LSR.
GR	Whether GR is enabled on the peer: · On—Enabled. · Off—Disabled.
MD5	Whether MD5 authentication is enabled for the LDP session on the local device: · On—Enabled. · Off—Disabled.
KA Sent/Rcvd	Number of keepalive messages sent/received.

# Display detailed information about all LDP peers and LDP sessions for the public network.

<Sysname> display mpls ldp peer verbose

Peer LDP ID : 100.100.100.20:0

Local LDP ID : 100.100.100.17:0

TCP Connection : 100.100.100.20:47515 -> 100.100.100.17:646

Session State : Operational Session Role : Passive

Session Up Time : 0000:00:03 (DD:HH:MM)

Max PDU Length : 4096 bytes (Local: 4096 bytes, Peer: 4096 bytes)

Keepalive Time : 45 sec (Local: 45 sec, Peer: 45 sec)

Keepalive Interval : 15 sec

Msgs Sent/Rcvd : 288/426

KA Sent/Rcvd : 13/13

Label Adv Mode : DU Graceful Restart : On

Reconnect Time : 120 sec Recovery Time : 360 sec

Loop Detection : On Path Vector Limit: 32

Discovery Sources:

Targeted Hello 100.100.100.17 -> 100.100.100.20 (Active, Passive)

Hello Hold Time: 45 sec Hello Interval : 15000 ms

Vlan-interface10

Hello Hold Time: 15 sec Hello Interval : 5000 ms

Label Acceptance Policy :

prefix-from-20

Session Protection : On

State : Ready Duration : 120 sec

Addresses received from peer:

202.118.224.20 100.100.100.20 11.22.33.44 1.2.3.10

1.2.3.4

Table 9 Command output

Field	Description
Peer LDP ID	LDP identifier of the peer.
Local LDP ID	LDP identifier of the local LSR.
TCP connection	TCP connection information for the session. It includes the IP addresses and port numbers used by both ends of the TCP connection, and whether MD5 authentication is enabled for the TCP connection. If MD5 authentication is enabled, this field displays MD5 On. If MD5 is not enabled, this field does not display MD5 information.
Session State	State of the LDP session: · Non Existent—No TCP connection is established. · Initialized—A TCP connection has been established. · OpenRecv—LDP has received an acceptable initialization message. · OpenSent—LDP has sent an initialization message. · Operational—An LDP session has been established.
Session Role	Role the local LSR in the session: Active or Passive.
Session Up time	Duration of the session in Operational state.
Max PDU Length	Maximum PDU length negotiated, in bytes. · Local—Maximum PDU length (in bytes) on the local LSR. · Peer—Maximum PDU length (in bytes) on the peer.
Keepalive Time	Keepalive time negotiated, in seconds. · Local—Locally configured Keepalive holding time in seconds. · Peer—Keepalive holding time (in seconds) configured on the peer.
Keepalive Interval	Keepalive interval in seconds.
Msgs Sent/Rcvd	Total number of LDP messages sent and received.
KA Sent/Rcvd	Total number of Keepalive messages sent and received.
Label Adv Mode	Label advertisement mode negotiated. The device only supports the DU mode.
Graceful Restart	Whether GR is enabled on the peer: · On—Enabled. · Off—Disabled.
Reconnect Time	Reconnect time negotiated, in seconds.
Recovery Time	Recovery time (in seconds) carried in packets sent by the peer.
Loop Detection	Whether loop detection is enabled on the peer: · On—Enabled. · Off—Disabled.
Path Vector Limit	Maximum Path Vector length configured on the peer.
Discovery Sources	Discovery source of the LDP peer.
Targeted Hello	LDP peer discovered by the extended discovery mechanism. · The address before -> (100.100.100.17 in this example) is the local IP address. · The address after -> (100.100.100.20 in this example) is the peer IP address. · (Active) indicates that the local LSR is the active end. It actively sends Targeted Hellos to its peer. · (Passive) indicates that the local LSR is the passive end. It passively responds to the Targeted Hellos from its peer. · (Active, Passive) indicates that the local LSR acts as both the active end and the passive end.
Vlan-interface10	Interface running LDP basic discovery. The device discovers the LDP peer by sending Link Hellos out of the interface.
Hello Hold Time	Hello hold time negotiated, in seconds.
Hello Interval	Current Hello interval, in milliseconds.
Label Acceptance Policy	Label acceptance policy used to filter label mappings received from the peer.
Session Protection	Whether session protection is enabled: · On—Enabled. · Off—Disabled.
State	Session protection state: · Incomplete—Session protection is not ready. · Ready—Session protection is ready. · Protecting—The session is under protection.
Duration	Local session protection duration, in seconds. Infinite indicates that session protection takes effect permanently.
Holdup time remaining	Remaining time of the session hold timer, in seconds. This field is displayed only when the session protection state is Protecting. A value of Infinite indicates that session protection takes effect permanently.
Addresses received from peer	IP addresses received from the peer.

display mpls ldp summary

Use display mpls ldp summary to display LDP summary information.

Syntax

display mpls ldp summary [ all | vpn-instance vpn-instance-name ]

Views

Any view

Predefined user roles

network-admin

network-operator

Parameters

all: Displays LDP summary information for the public network and all VPN instances.

vpn-instance vpn-instance-name: Displays LDP summary information for the specified VPN instance. The vpn-instance-name argument is a case-sensitive string of 1 to 31 characters.

Usage guidelines

If you do not specify any parameters, this command displays LDP summary information for the public network.

Examples

# Display LDP summary information for the public network.

<Sysname> display mpls ldp summary

VPN Instance Name : Public

Instance ID : 0

Instance State : Active

Interfaces : 1 (1 active)

Targeted Peers : 0

Adjacencies : 1

Peers : 1

Operational : 1 (0 GR)

OpenSent : 0

OpenRecv : 0

Initialized : 0

Non-Existent: 0

Table 10 Command output

Field	Description
Instance ID	VPN instance identifier. A value of 0 represents the public network.
Instance State	LDP status in the VPN instance: Active or Inactive.
Interfaces	Number of interfaces enabled with LDP. active: Number of interfaces running LDP.
Targeted Peers	Number of LDP IPv4 peers discovered by the LDP extended discovery mechanism, including the manually specified peers and the automatically established peers.
Adjacencies	Number of IPv4 Hello adjacencies.
Peers	Total number of peers.
Operational	Number of peers in Operational state. GR: Number of GR-capable peers.
OpenSent	Number of peers in OpenSent state.
OpenRecv	Number of peers in OpenRecv state.
Initialized	Number of peers in Initialized state.
Non-Existent	Number of peers in Non-Existent state.

dscp

Use dscp to set a DSCP value for outgoing LDP packets.

Use undo dscp to restore the default.

Syntax

dscp dscp-value

undo dscp

Default

The DSCP value for outgoing LDP packets is 48.

Views

LDP view

Predefined user roles

network-admin

Parameters

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

Usage guidelines

To control the transmission preference of outgoing LDP packets, set a DSCP value for outgoing LDP packets.

Examples

# Set the DSCP value for outgoing LDP packets to 56.

<Sysname> system-view

[Sysname] mpls ldp

[Sysname-ldp] dscp 56

Related commands

display mpls ldp parameter

graceful-restart

Use graceful-restart to enable Graceful Restart (GR) for LDP.

Use undo graceful-restart to disable LDP GR.

Syntax

graceful-restart

undo graceful-restart

Default

LDP GR is disabled.

Views

LDP view

Predefined user roles

network-admin

Usage guidelines

LDP GR enables an LSR to retain MPLS forwarding entries during an LDP restart, ensuring continuous MPLS forwarding.

The configuration of this command takes effect only on new LDP sessions. To apply the configuration to existing LDP sessions, you must reset the LDP sessions by using the reset mpls ldp command.

Examples

# Enable GR for LDP.

<Sysname> system-view

[Sysname] mpls ldp

[Sysname-ldp] graceful-restart

Related commands

display mpls ldp parameter

reset mpls ldp

graceful-restart timer

Use graceful-restart timer to set the MPLS Forwarding State Holding timer and the Reconnect timer for GR.

Use undo graceful-restart timer to restore the default.

Syntax

graceful-restart timer { forwarding-hold hold-time | reconnect reconnect-time }

undo graceful-restart timer { forwarding-hold | reconnect }

Default

The MPLS Forwarding State Holding timer is 180 seconds and the Reconnect timer is 120 seconds.

Views

LDP view

Predefined user roles

network-admin

Parameters

forwarding-hold hold-time: Specifies the MPLS Forwarding State Holding time in the range of 60 to 6000 seconds. This time specifies how long the local LSR retains its MPLS forwarding entries after the control plane of the local LSR restarts.

reconnect reconnect-time: Specifies the Reconnect time in the range of 60 to 300 seconds. This time specifies the period the local LSR expects the peer to wait for LDP session re-establishment after the peer detects an LDP session failure. The local LSR sends the Reconnect time to the peer.

Usage guidelines

The MPLS Forwarding State Holding time must be greater than the Reconnect time.

The configuration of this command takes effect only on new LDP sessions. To apply the configuration to existing LDP sessions, you must reset the LDP sessions by using the reset mpls ldp command.

Examples

# Set the MPLS Forwarding State Holding time to 200 seconds, and the Reconnect time to 100 seconds.

<Sysname> system-view

[Sysname] mpls ldp

[Sysname-ldp] graceful-restart timer forwarding-hold 200

[Sysname-ldp] graceful-restart timer reconnect 100

Related commands

display mpls ldp parameter

graceful-restart

label-distribution

Use label-distribution to configure the label distribution control mode.

Use undo label-distribution to restore the default.

Syntax

label-distribution { independent | ordered }

undo label-distribution

Default

The label distribution control mode is ordered.

Views

LDP view

LDP-VPN instance view

Predefined user roles

network-admin

Parameters

independent: Specifies Independent label distribution mode. In this mode, an LSR can distribute label mappings to the upstream LSR at any time.

ordered: Specifies Ordered label distribution mode. In this mode, an LSR distributes a label mapping for an FEC to the upstream LSR only when one of the following events occurs:

· The LSR receives a label mapping for that FEC from the downstream LSR.

· The LSR is the egress node of that FEC.

Usage guidelines

In Ordered mode, an LSR can determine that the downstream LSR has established an LSP when the LSR receives an FEC-label mapping from the downstream LSR.

The Independent mode enables faster LSP convergence because each LSR independently advertises labels without waiting for labels from downstream LSRs.

Examples

# Set the Independent LDP label distribution mode for the public network.

<Sysname> system-view

[Sysname] mpls ldp

[Sysname-ldp] label-distribution independent

Related commands

display mpls ldp parameter

loop-detect

Use loop-detect to enable loop detection.

Use undo loop-detect to disable loop detection.

Syntax

loop-detect

undo loop-detect

Default

Loop detection is disabled.

Views

LDP view

LDP-VPN instance view

Predefined user roles

network-admin

Usage guidelines

The LDP loop detection feature enables LDP to detect loops during an LSP establishment. If LDP detects a loop, it terminates the LSP establishment. This feature is applicable to an MPLS network where most of the devices do not support the TTL mechanism, such as ATM switches.

LDP uses hop count (see "maxhops") and path vector (see "pv-limit") for loop detection.

To use this feature, you must enable it on all LSRs that the LSP passes through.

To avoid extra LDP overhead, do not use this feature if most of the devices in an MPLS network support the TTL mechanism. Using the TTL mechanism can prevent endless routing loops.

The configuration of this command takes effect only on new LDP sessions. To apply the configuration to existing LDP sessions, you must reset the LDP sessions by using the reset mpls ldp command.

Examples

# Enable LDP loop detection for the public network.

<Sysname> system-view

[Sysname] mpls ldp

[Sysname-ldp] loop-detect

Related commands

display mpls ldp parameter

maxhops

pv-limit

lsr-id

Use lsr-id to configure an LDP LSR ID.

Use undo lsr-id to restore the default.

Syntax

lsr-id lsr-id

undo lsr-id

Default

No LDP LSR ID is configured. LDP uses the MPLS LSR ID configured by the mpls lsr-id command for both the public network and VPN instances.

Views

LDP view

LDP-VPN instance view

Predefined user roles

network-admin

Parameters

lsr-id: Specifies an LDP LSR ID, in dotted decimal notation.

Usage guidelines

If you configure an LDP LSR ID by using the lsr-id command in LDP view or LDP-VPN instance view, LDP uses the LDP LSR ID. If no LDP LSR ID is configured, LDP uses the LSR ID configured by the mpls lsr-id command.

All LDP sessions in the same VPN instance use the same LDP LSR ID. If you change the LDP LSR ID for a VPN instance, all LDP sessions in the VPN instance will be deleted and then re-established.

As a best practice, use the default LDP LSR ID configured by the mpls lsr-id command for the public network. If the lsr-id command is required to configure an LDP LSR ID for the public network, specify the IP address of a local loopback interface as the LDP LSR ID.

Examples

# Configure the LDP LSR ID as 2.2.2.2 for the public network.

<Sysname> system-view

[Sysname] mpls ldp

[Sysname-ldp] lsr-id 2.2.2.2

# Change the LDP LSR ID for the public network to 3.3.3.3.

[Sysname-ldp] lsr-id 3.3.3.3

All associated LDP sessions will be reset. Continue? [Y/N]:y

Related commands

display mpls ldp parameter

mpls lsr-id

maxhops

Use maxhops to set the maximum hop count for loop detection.

Use undo maxhops to restore the default.

Syntax

maxhops hop-number

undo maxhops

Default

The maximum hop count for loop detection is 32.

Views

LDP view

LDP-VPN instance view

Predefined user roles

network-admin

Parameters

hop-number: Specifies the maximum hop count for loop detection, in the range of 1 to 32.

Usage guidelines

LDP adds a hop count in a label request or label mapping message. The hop count increments by 1 on each LSR. When the hop count reaches the maximum hop count configured by this command, LDP considers that a loop occurs and terminates LSP establishment.

Set a proper maximum hop count according to the number of LSRs in your network. For example, set a smaller maximum hop count in small networks to allow for fast loop detection. Set a higher maximum hop count in large networks to ensure that LSPs can be successfully established.

The configuration of this command takes effect only on new LDP sessions. To apply the configuration to existing LDP sessions, you must reset the LDP sessions by using the reset mpls ldp command.

Examples

# Set the maximum hop count to 25 for loop detection on the public network.

<Sysname> system-view

[Sysname] mpls ldp

[Sysname-ldp] maxhops 25

Related commands

display mpls ldp parameter

loop-detect

pv-limit

md5-authentication

Use md5-authentication to enable LDP MD5 authentication.

Use undo md5-authentication to disable LDP MD5 authentication.

Syntax

md5-authentication peer-lsr-id { cipher | plain } string

undo md5-authentication peer-lsr-id

Default

LDP MD5 authentication is disabled.

Views

LDP view

LDP-VPN instance view

Predefined user roles

network-admin

Parameters

peer-lsr-id: Specifies the LSR ID of a peer.

cipher: Specifies a key in encrypted form.

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

string: Specifies the key. 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

To improve security for LDP sessions, you can configure MD5 authentication for the underlying TCP connections to check the integrity of LDP messages.

For the local LSR and the peer LSR to establish a TCP connection, they must have the same key.

MD5 authentication key settings take effect only on new LDP sessions. To apply the new settings to existing LDP sessions, you must reset the LDP sessions by using the reset mpls ldp command.

Examples

# Enable LDP MD5 authentication for peer 3.3.3.3 on the public network, and set a key of pass in plaintext form.

<Sysname> system-view

[Sysname] mpls ldp

[Sysname-ldp] md5-authentication 3.3.3.3 plain pass

Related commands

display mpls ldp peer

mpls ldp

Use mpls ldp to enable LDP globally for an LSR and enter LDP view.

Use undo mpls ldp to disable LDP globally for an LSR and delete all LDP-VPN instances.

Syntax

mpls ldp

undo mpls ldp

Default

LDP is globally disabled.

Views

System view

Predefined user roles

network-admin

Usage guidelines

You must enable LDP globally for an LSR to run LDP.

The NSR ,and GR commands, the session protection command, and the targeted-peer command are available only in LDP view. All other commands available in LDP view are also available in LDP-VPN instance view.

Commands executed in LDP view take effect only on the public network. Commands executed in LDP-VPN instance view take effect only on the specified VPN instance. The NSR and GR commands are global commands and take effect on all VPN instances and the public network.

Examples

# Enable LDP globally and enter LDP view.

<Sysname> System-view

[Sysname] mpls ldp

[Sysname-ldp]

Related commands

mpls ldp enable

vpn-instance

mpls ldp timer

Use mpls ldp timer to set the Hello hold time, Hello interval, Keepalive hold time, and Keepalive interval.

Use undo mpls ldp timer to restore the default.

Syntax

mpls ldp timer { hello-hold timeout | hello-interval interval | keepalive-hold timeout | keepalive-interval interval }

undo mpls ldp timer { hello-hold | hello-interval | keepalive-hold | keepalive-interval }

Default

· The Link Hello hold time is 15 seconds.

· The Link Hello interval is 5 seconds.

· The Targeted Hello hold time is 45 seconds.

· The Targeted Hello interval is 15 seconds.

· The Keepalive hold time is 45 seconds.

· The Keepalive interval is 15 seconds.

Views

Interface view

LDP peer view

Predefined user roles

network-admin

Parameters

hello-hold timeout: Specifies the Hello hold time in the range of 1 to 65535 seconds. LDP keeps the hello adjacency during the Hello hold time. The negotiated Hello hold time takes the smaller value of the local Hello hold time and the peer Hello hold time. If LDP receives no Hello message from the peer before the Hello hold timer expires, LDP deletes the Hello adjacency with the peer. If you set the Hello hold time to 65535, LDP permanently keeps the Hello adjacency.

hello-interval interval: Specifies the Hello interval in the range of 1 to 65535 seconds. LDP sends Hello messages at this interval.

keepalive-hold timeout: Specifies the Keepalive hold time in the range of 15 to 65535 seconds. LDP keeps the LDP session to the peer during the Keepalive hold time. The negotiated Keepalive hold time takes the smaller value of the local Keepalive hold time and the peer Keepalive hold time. If LDP receives no LDP message from the peer before the Keepalive hold timer expires, LDP deletes the LDP session to the peer.

keepalive-interval interval: Specifies the Keepalive interval in the range of 1 to 65535 seconds. LDP sends Keepalive messages to the peer at this interval.

Usage guidelines

In interface view, this command sets a Link Hello hold time and a Link Hello interval.

In LDP peer view, this command sets a Targeted Hello hold time and a Targeted Hello interval.

LDP automatically sends Targeted Hellos to the specified peer after one of the following features is configured:

· LDP session protection.

· MPLS L2VPN LDP PW.

· VPLS LDP PW.

To modify the Targeted Hello/Keepalive hold time and interval, you must use the targeted-peer command to create the LDP peer, and then perform the modification in the LDP peer view.

If the local Hello hold time and local Keepalive hold time are different from those of a peer LSR, the negotiation is as follows:

· During LDP peer discovery, an LSR compares the local Hello hold time with the peer LSR's Hello hold time carried in Hellos. Then, the LSR uses the smaller one as the negotiated Hello hold time.

¡ If the negotiated Hello hold time is larger than three times the local Hello interval, the LSR sends Hello messages at the local Hello interval.

¡ If it is not larger than three times the local Hello interval, the LSR sends Hello messages at an interval 1/3 of the negotiated Hello hold time.

· During LDP session negotiation, an LSR compares the local Keepalive hold time with the Keepalive hold time of the peer LSR by exchanging Initialization messages. Then, the LSR uses the smaller one as the negotiated Keepalive hold time.

¡ If the negotiated Keepalive hold time is larger than three times the local Keepalive interval, the LSR sends Keepalive messages at the local Keepalive interval.

¡ If it is not larger than three times the local Keepalive interval, the LSR sends Keepalive messages at an interval 1/3 of the negotiated Keepalive hold time.

If the Hello hold time and the Keepalive hold time values are too large, LDP cannot quickly detect link failures. If the values are too small, LDP might mistakenly consider a normal link failed. As a best practice, use the default values.

Make sure all links between two LSRs have the same Keepalive hold time as the one configured in LDP peer view in either of the following situations:

· Multiple Link Hello adjacencies exist when the two LSRs are directly connected through multiple links.

· Both a Link Hello adjacency and a Targeted Hello adjacency exist between the two LSRs.

Keepalive hold time and keepalive interval settings take effect only on new LDP sessions. To apply the settings to existing LDP sessions, you must reset the LDP sessions by using the reset mpls ldp command.

Examples

# Set the Targeted Hello hold time to 1000 seconds, Targeted Hello interval to 50 seconds, Keepalive hold time to 1000 seconds, and Keepalive interval to 50 seconds for peer 3.3.3.3.

<Sysname> System-view

[Sysname] mpls ldp

[Sysname-ldp] targeted-peer 3.3.3.3

[Sysname-ldp-peer-3.3.3.3] mpls ldp timer hello-hold 1000

[Sysname-ldp-peer-3.3.3.3] mpls ldp timer hello-interval 50

[Sysname-ldp-peer-3.3.3.3] mpls ldp timer keepalive-hold 1000

[Sysname-ldp-peer-3.3.3.3] mpls ldp timer keepalive-interval 50

# On VLAN-interface 2, set the Link Hello hold time to 100 seconds, Link Hello interval to 20 seconds, Keepalive hold time to 50 seconds, and Keepalive interval to 10 seconds.

<Sysname> System-view

[Sysname] interface vlan-interface 2

[Sysname-Vlan-interface2] mpls ldp timer hello-hold 100

[Sysname-Vlan-interface2] mpls ldp timer hello-interval 20

[Sysname-Vlan-interface2] mpls ldp timer keepalive-hold 50

[Sysname-Vlan-interface2] mpls ldp timer keepalive-interval 10

Related commands

display mpls ldp discovery

display mpls ldp peer

non-stop-routing

Use non-stop-routing to enable LDP NSR.

Use undo non-stop-routing to disable LDP NSR.

Syntax

non-stop-routing

undo non-stop-routing

Default

LDP NSR is disabled.

Views

LDP view

Predefined user roles

network-admin

Examples

# Enable LDP NSR.

<Sysname> system-view

[Sysname] mpls ldp

[Sysname-ldp] non-stop-routing

Related commands

display mpls ldp discovery

display mpls ldp fec

display mpls ldp peer

display mpls ldp summary

propagate mapping

Use propagate mapping to configure a label mapping propagation policy.

Use undo propagate mapping to restore the default.

Syntax

propagate mapping { none | prefix-list prefix-list-name }

undo propagate mapping

Default

No label mapping propagation policy is configured. The device advertises all IPv4 prefix label mappings permitted by the LSP generation policy.

Views

LDP view

LDP-VPN instance view

Predefined user roles

network-admin

Parameters

none: Does not advertise label mappings.

prefix-list prefix-list-name: Advertises the label mappings permitted by the specified prefix list. The prefix-list-name argument represents the name of the prefix list, a case-sensitive string of 1 to 63 characters.

Usage guidelines

In an LDP network, LSRs establish LSPs by advertising label mapping messages. When a PE acts as both an ingress LSR and a transit LSR, there might be a large number of transit LSPs on the PE. You can configure a label mapping propagation policy on the PE to reduce the number of transit LSPs and thus save network resources. A label mapping propagation policy allows the PE to advertise only permitted label mappings to the peers to establish transit LSPs.

If you execute both the lsp-trigger and propagate mapping commands, establishment of transit LSPs is controlled by the propagate mapping command.

Examples

# Configure the device to advertise label mappings only for routes 10.10.1.0/24 and 10.20.1.0/24.

<Sysname> system-view

[Sysname] ip prefix-list transit-fec-list index 1 permit 10.10.1.0 24

[Sysname] ip prefix-list transit-fec-list index 2 permit 10.20.1.0 24

[Sysname] mpls ldp

[Sysname-ldp] propagate mapping prefix-list transit-fec-list

Related commands

ip prefix-list (Layer 3—IP Routing Command Reference)

lsp-trigger

pv-limit

Use pv-limit to set the path vector limit.

Use undo pv-limit to restore the default.

Syntax

pv-limit pv-number

undo pv-limit

Default

The path vector limit is 32.

Views

LDP view

LDP-VPN instance view

Predefined user roles

network-admin

Parameters

pv-number: Specifies the path vector limit in the range of 1 to 32.

Usage guidelines

LDP adds LSR ID information in a label request or label mapping message. Each LSR checks whether its LSR ID is contained in the message.

· If it is not, the LSR adds its own LSR ID into the message.

· If it is, the LSR considers that a loop occurs and terminates LSP establishment.

In addition, when the number of LSR IDs in the message reaches the path vector limit, LDP also considers that a loop occurs and terminates LSP establishment.

The configuration of this command takes effect only on new LDP sessions. To apply the configuration to existing LDP sessions, you must reset the LDP sessions by using the reset mpls ldp command.

Examples

# Set the path vector limit to 3 for LDP loop detection on the public network.

<Sysname> system-view

[Sysname] mpls ldp

[Sysname-ldp] pv-limit 3

Related commands

display mpls ldp parameter

loop-detect

maxhops

reset mpls ldp

Use reset mpls ldp to reset LDP sessions.

Syntax

reset mpls ldp [ vpn-instance vpn-instance-name ] [ peer peer-id ]

Views

User view

Predefined user roles

network-admin

Parameters

vpn-instance vpn-instance-name: Specifies an MPLS L3VPN instance by its name, a case-sensitive string of 1 to 31 characters. This command resets the LDP sessions in the specified VPN instance. If you do not specify a VPN instance, this command resets the LDP sessions in the public network.

peer peer-id: Specifies a peer by its LSR ID. If you do not specify a peer, this command resets all LDP sessions in the specified VPN instance or the public network.

Usage guidelines

Resetting an LDP session deletes and re-establishes the session and all LSPs based on the session.

Changes to LDP session parameters take effect only on new LDP sessions. To apply the changes to an existing LDP session on a network, you must reset all LDP sessions on that network by executing this command without the peer keyword. If you specify the peer keyword, this command resets the LDP session to the specified peer without applying the parameter changes to the session.

Examples

# Reset all LDP sessions in the public network.

<Sysname> reset mpls ldp

# Reset all LDP sessions in VPN instance vpn1.

<Sysname> reset mpls ldp vpn-instance vpn1

snmp-agent trap enable ldp

Use snmp-agent trap enable ldp to enable SNMP notifications for LDP.

Use undo snmp-agent trap enable ldp to disable SNMP notifications for LDP.

Syntax

snmp-agent trap enable ldp

undo snmp-agent trap enable ldp

Default

SNMP notifications for LDP are enabled.

Views

System view

Predefined user roles

network-admin

Usage guidelines

This command enables generating SNMP notifications for LDP upon LDP session changes, as defined in RFC 3815. For LDP 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 LDP.

<Sysname> system-view

[Sysname] snmp-agent trap enable ldp

vpn-instance

Use vpn-instance to enable LDP for a VPN instance (create an LDP-VPN instance) and enter LDP-VPN instance view, or enter the view of an existing LDP-VPN instance.

Use undo vpn-instance to delete the LDP-VPN instance.

Syntax

vpn-instance vpn-instance-name

undo vpn-instance vpn-instance-name

Default

LDP is disabled for a VPN instance.

Views

LDP view

Predefined user roles

network-admin

Parameters

vpn-instance-name: Specifies a VPN instance by its name, a case-sensitive string of 1 to 31 characters. The VPN instance must have been created by the ip vpn-instance command in system view.

Usage guidelines

Enabling LDP for VPN instances is used for the Carrier's Carrier network that uses LDP between the Level 1 carrier and Level 2 carrier PEs. In such a network, you must enable LDP for each VPN instance on each Level 1 carrier PE.

The GR, NSR, and LDP-IGP synchronization commands, the dscp command, the session protection command, and the targeted-peer command are available only in LDP view. All other commands available in LDP view are available in LDP-VPN instance view.

Commands executed in LDP view take effect only on the public network. Commands executed in LDP-VPN instance view take effect only on the specified VPN instance. The dscp command, NSR commands, and GR commands are global commands and take effect on all VPN instances and the public network.

Examples

# Enable LDP for VPN instance vpn1 and enter LDP-VPN instance view.

<Sysname> system-view

[Sysname] mpls ldp

[Sysname-ldp] vpn-instance vpn1

[Sysname-ldp-vpn-instance-vpn1]

Related commands

ip vpn-instance

mpls ldp

IPv4 LDP commands

accept-label

Use accept-label to configure a label acceptance policy.

Use undo accept-label to delete a label acceptance policy.

Syntax

accept-label peer peer-lsr-id prefix-list prefix-list-name

undo accept-label peer peer-lsr-id

Default

No label acceptance policy is configured. LDP accepts all IPv4 FEC-label mappings from all peers.

Views

LDP view

LDP-VPN instance view

Predefined user roles

network-admin

Parameters

peer peer-lsr-id: Specifies an LDP peer by its LSR ID.

prefix-list prefix-list-name: Specifies an IPv4 prefix list by its name, a case-sensitive string of 1 to 63 characters.

Usage guidelines

This feature enables you to control the number of FEC-label mappings received from peers. LDP accepts only the FEC-label mappings whose IPv4 prefixes are permitted by the specified IPv4 prefix list from the specified peer.

To accept the previously denied label mappings from a peer, use the undo accept-label command or change the IPv4 prefix list for the peer. Then, execute the reset mpls ldp command to reset the LDP session to that peer to apply the new settings.

Using a label advertisement policy on an LSR or using a label acceptance policy on its upstream LSR can achieve the same purpose. As a best practice, use the label advertisement policy to reduce network load.

Examples

# Configure a label acceptance policy to accept only the FEC-label mappings containing IPv4 prefixes 10.1.1.0/24 and 10.2.1.0/24 from LDP peer 1.1.1.9.

<Sysname> system-view

[Sysname] ip prefix-list prefix-from-RTA index 1 permit 10.1.1.0 24

[Sysname] ip prefix-list prefix-from-RTA index 2 permit 10.2.1.0 24

[Sysname] mpls ldp

[Sysname-ldp] accept-label peer 1.1.1.9 prefix-list prefix-from-RTA

Related commands

display mpls ldp peer verbose

ip prefix-list (Layer 3—IP Routing Command Reference)

advertise-label

Use advertise-label to configure a label advertisement policy.

Use undo advertise-label to delete a label advertisement policy.

Syntax

advertise-label prefix-list prefix-list-name [ peer peer-prefix-list-name ]

undo advertise-label prefix-list prefix-list-name

Default

No label advertisement policy is configured. The device advertises IPv4 FEC-label mappings permitted by the LSP generation policy to all peers.

Views

LDP view

LDP-VPN instance view

Predefined user roles

network-admin

Parameters

prefix-list prefix-list-name: Specifies an IPv4 prefix list by its name, a case-sensitive string of 1 to 63 characters. This prefix list filters advertised label mappings.

peer peer-prefix-list-name: Specifies an IPv4 prefix list by its name, a case-sensitive string of 1 to 63 characters. This prefix list filters LDP peers. If you do not specify this option, the device advertises label mappings to all peers.

Usage guidelines

Use a label advertisement policy to filter label mappings advertised to peers.

Configure multiple label advertisement policies by executing this command multiple times.

If a label mapping is permitted by an advertisement policy, LDP advertises the mapping by following these rules:

· If the policy has no peer IPv4 prefix list (peer peer-prefix-list-name not specified), LDP advertises the label mapping to all peers.

· If the policy has a peer IPv4 prefix list, LDP advertises the label mapping to the peers permitted by the peer IPv4 prefix list.

If a label mapping is permitted by multiple advertisement policies, LDP advertises the label mapping according to the first configured policy.

Examples

# Configure two label advertisement policies. One policy advertises only the label mapping for subnet 10.1.1.0/24 to peer 3.3.3.9. The other policy advertises only the label mapping for subnet 10.2.1.0/24 to peer 4.4.4.9.

<Sysname> system-view

[Sysname] ip prefix-list prefix-to-C permit 10.1.1.0 24

[Sysname] ip prefix-list prefix-to-D permit 10.2.1.0 24

[Sysname] ip prefix-list peer-C permit 3.3.3.9 32

[Sysname] ip prefix-list peer-D permit 4.4.4.9 32

[Sysname] mpls ldp

[Sysname-ldp] advertise-label prefix-list prefix-to-C peer peer-C

[Sysname-ldp] advertise-label prefix-list prefix-to-D peer peer-D

Related commands

display mpls ldp fec

ip prefix-list (Layer 3—IP Routing Command Reference)

lsp-trigger

display mpls ldp igp sync

Use display mpls ldp igp sync to display LDP-IGP synchronization information.

Syntax

display mpls ldp igp sync [ interface interface-type interface-number ]

Views

Any view

Predefined user roles

network-admin

network-operator

Parameters

interface interface-type interface-number: Specifies an interface by its type and number. If you do not specify an interface, this command displays LDP-IGP synchronization information for all interfaces.

Examples

# Display LDP-IGP synchronization information for all interfaces.

<Sysname> display mpls ldp igp sync

Vlan-interface10:

IGP protocols: OSPF

Sync status: Ready

Peers:

10.1.1.2:0

Vlan-interface20:

IGP protocols: OSPF, IS-IS

Sync status: Delayed (24 sec remaining)

Peers:

20.1.1.2:0

Vlan-interface30:

LDP-IGP synchronization is disabled on the interface

Table 11 Command output

Field	Description
IGP protocols	IGP protocols that require LDP-IGP synchronization: OSPF and IS-IS.
Sync status	LDP-IGP synchronization state: · Ready—LDP is converged and is available for IGP. · Delayed—LDP is waiting to notify IGP of the convergence. remaining indicates the remaining time for the delay, in seconds. · Not ready—LDP is not converged and is not available for IGP. · LDP not enabled—LDP is not enabled on the interface.
Peers	LDP peer that completes LDP convergence on the interface.

igp sync delay

Use igp sync delay to set the delay for LDP to notify IGP of the LDP convergence completion.

Use undo igp sync delay to restore the default.

Syntax

igp sync delay time

undo igp sync delay

Default

LDP immediately notifies IGP of the LDP convergence completion.

Views

LDP view

Predefined user roles

network-admin

Parameters

time: Specifies the notification delay in the range of 5 to 300 seconds.

Usage guidelines

LDP convergence on a link is completed when the following conditions exist:

· The local device establishes an LDP session to a minimum of one peer, and the LDP session is already in Operational state.

· The local device has distributed the label mappings to a minimum of one peer.

If LDP notifies IGP immediately after convergence, MPLS traffic forwarding might be interrupted in one of the following scenarios:

· LDP peers use the Ordered label distribution control mode. When LDP notifies IGP of the LDP convergence, the device has not received a label mapping from downstream.

· A large number of label mappings are distributed from downstream. When LDP notifies IGP of the LDP convergence completion, label advertisement is not completed.

In these scenarios, you must use the igp sync delay command to configure the notification delay. When LDP convergence on a link is completed, LDP waits a delay time before notifying IGP of the LDP convergence completion to reduce traffic interruption.

Examples

# Set a 30-second delay for LDP to notify IGP of the LDP convergence.

<Sysname> system-view

[Sysname] mpls ldp

[Sysname-ldp] igp sync delay 30

Related commands

igp sync delay on-restart

mpls ldp igp sync disable

mpls ldp sync (IS-IS view)

mpls ldp sync (OSPF view/OSPF area view)

igp sync delay on-restart

Use igp sync delay on-restart to set the maximum delay for LDP to notify IGP of the LDP-IGP synchronization status after an LDP restart or an active/standby switchover occurs.

Use undo igp sync delay on-restart to restore the default.

Syntax

igp sync delay on-restart time

undo igp sync delay on-restart

Default

The maximum notification delay is 90 seconds.

Views

LDP view

Predefined user roles

network-admin

Parameters

time: Specifies the maximum notification delay in the range of 60 to 600 seconds.

Usage guidelines

When an LDP restart or an active/standby switchover occurs, LDP takes time to converge. LDP notifies IGP of the LDP-IGP synchronization status as follows:

· If a notification delay is not configured, LDP immediately notifies IGP of the current synchronization states during convergence, and then updates the states after LDP convergence. This could impact IGP processing.

· If a notification delay is configured, LDP notifies IGP of the synchronization states in bulk when one of the following events occurs:

¡ LDP recovers to the state before the restart or switchover.

¡ The maximum delay timer expires.

Examples

# Set a 300-second maximum delay for LDP to notify IGP of the LDP-IGP synchronization status after an LDP restart or active/standby switchover occurs.

<Sysname> system-view

[Sysname] mpls ldp

[Sysname-ldp] igp sync delay on-restart 300

Related commands

igp sync delay

mpls ldp igp sync disable

mpls ldp sync (IS-IS view)

mpls ldp sync (OSPF view/OSPF area view)

import bgp

Use import bgp to enable LDP to redistribute BGP IPv4 unicast routes.

Use undo import bgp to disable LDP from redistributing BGP IPv4 unicast routes.

Syntax

import bgp [ as-number ]

undo import bgp

Default

LDP does not redistribute BGP IPv4 unicast routes.

Views

LDP view

LDP-VPN instance view

Predefined user roles

network-admin

Parameters

as-number: Redistributes BGP IPv4 unicast routes in the specified AS. An AS number is in the range of 1 to 4294967295. If you do not specify an AS number, this command enables LDP to redistribute all BGP IPv4 unicast routes.

Usage guidelines

IMPORTANT:

Use this command only if necessary. Execution of this command will increase the number of routes redistributed to LDP. A large number of redistributed routes will use a large amount of labels and memory.

By default, LDP automatically redistributes IPv4 IGP routes, including the BGP IPv4 unicast routes that have been redistributed into IGP. Then, LDP assigns labels to the IGP routes and labeled BGP routes if these routes are permitted by an LSP generation policy. LDP does not automatically redistribute BGP IPv4 unicast routes if the routes are not redistributed into the IGP.

For example, on a carrier's carrier network where IGP is not configured between a PE of a Level 1 carrier and a CE of a Level 2 carrier, LDP cannot redistribute BGP IPv4 unicast routes to assign labels to them. For this network to operate correctly, you can enable LDP to redistribute BGP IPv4 unicast routes. If the routes are permitted by an LSP generation policy, LDP assigns labels to them to establish LSPs. For more information about carrier's carrier, see MPLS Configuration Guide.

If you execute this command multiple times, the most recent configuration takes effect.

Examples

# Enable LDP to redistribute BGP IPv4 unicast routes in AS 100 on the public network.

<Sysname> system-view

[Sysname] mpls ldp

[Sysname-ldp] import bgp 100

Related commands

lsp-trigger

Use lsp-trigger to configure an LSP generation policy for IPv4 FECs.

Use undo lsp-trigger to restore the default.

Syntax

lsp-trigger { all | prefix-list prefix-list-name }

undo lsp-trigger

Default

LDP only uses redistributed IPv4 host routes with a 32-bit mask to generate LSPs.

Views

LDP view

LDP-VPN instance view

Predefined user roles

network-admin

Parameters

all: Enables LDP to use all redistributed routes to generate LSPs.

prefix-list prefix-name: Specifies an IPv4 prefix list by its name, a case-sensitive string of 1 to 63 characters. LDP uses only the redistributed routes permitted by the IPv4 prefix list to generate LSPs.

Usage guidelines

LDP assigns labels to the routes that have been redistributed into LDP to generate LSPs. An LSP generation policy specifies the routes that LDP uses to generate LSPs.

The default LSP generation policy depends on the label distribution control mode.

· In Ordered mode, LDP can only use the following routes to generate LSPs:

¡ Loopback interface address routes with a 32-bit mask.

¡ The routes with a 32-bit mask that match the FECs of label mappings received from downstream LSRs.

· In Independent mode, LDP can use all routes with a 32-bit mask to generate LSPs.

After you configure an LSP generation policy, LDP uses all redistributed routes or those permitted by the IPv4 prefix list to generate LSPs, regardless of the label distribution control mode.

As a best practice, use the default LSP generation policy.

Examples

# Configure an LSP generation policy that enables LDP to use only redistributed routes 10.10.1.0/24 and 10.20.1.0/24 to establish LSPs for the public network.

<Sysname> system-view

[Sysname] ip prefix-list egress-fec-list index 1 permit 10.10.1.0 24

[Sysname] ip prefix-list egress-fec-list index 2 permit 10.20.1.0 24

[Sysname] mpls ldp

[Sysname-ldp] lsp-trigger prefix-list egress-fec-list

Related commands

import bgp

ip prefix-list (Layer 3—IP Services Command Reference)

mpls ldp enable

Use mpls ldp enable to enable IPv4 LDP on an interface.

Use undo mpls ldp enable to disable IPv4 LDP on an interface.

Syntax

mpls ldp enable

undo mpls ldp enable

Default

IPv4 LDP is disabled on an interface.

Views

Interface view

Predefined user roles

network-admin

Usage guidelines

An up interface enabled with IPv4 LDP and MPLS sends IPv4 Link Hellos for neighbor discovery.

Before you enable IPv4 LDP on an interface, use the mpls ldp command in system view to enable LDP globally. If the interface is bound to a VPN instance, you must also use the vpn-instance command to enable LDP for the VPN instance.

Disabling LDP on an interface terminates all LDP sessions on the interface, and removes all LSPs established through the sessions.

Examples

# Enable IPv4 LDP on VLAN-interface 2.

<Sysname> system-view

[Sysname] mpls ldp

[Sysname-ldp] quit

[Sysname] interface vlan-interface 2

[Sysname-Vlan-interface2] mpls ldp enable

Related commands

display mpls ldp interface

mpls enable

mpls ldp

mpls ldp igp sync disable

Use mpls ldp igp sync disable to disable LDP-IGP synchronization on an interface.

Use undo mpls ldp igp sync disable to enable LDP-IGP synchronization on an interface.

Syntax

mpls ldp igp sync disable

undo mpls ldp igp sync disable

Default

LDP-IGP synchronization is enabled on an interface.

Views

Interface view

Predefined user roles

network-admin

Usage guidelines

After you enable LDP-IGP synchronization for an OSPF area or an IS-IS process, LDP-IGP synchronization is enabled on the OSPF or IS-IS process interfaces by default. To disable LDP-IGP synchronization on an interface, execute the mpls ldp igp sync disable command on that interface.

Examples

# Disable LDP-IGP synchronization on VLAN-interface 2.

<Sysname> System-view

[Sysname] interface vlan-interface 2

[Sysname-Vlan-interface2] mpls ldp igp sync disable

Related commands

mpls ldp sync (IS-IS view)

mpls ldp sync (OSPF view/OSPF area view)

mpls ldp sync (IS-IS view)

Use mpls ldp sync to enable LDP-ISIS synchronization.

Use undo mpls ldp sync to disable LDP-ISIS synchronization.

Syntax

mpls ldp sync [ level-1 | level-2 ]

undo mpls ldp sync [ level-1 | level-2 ]

Default

LDP-ISIS synchronization is disabled.

Views

IS-IS view

Predefined user roles

network-admin

Parameters

level-1: Specifies Level-1 of the IS-IS process.

level-2: Specifies Level-2 of the IS-IS process.

Usage guidelines

LDP establishes LSPs based on the IGP optimal route. If LDP is not synchronized with IGP, MPLS traffic forwarding might be interrupted. The LDP-IGP synchronization feature is used to solve the synchronization problem.

After LDP-IGP synchronization is enabled, IGP advertises the actual cost of a link only when LDP convergence on the link is completed. Before LDP is converged, IGP advertises the maximum cost of the link. As a result, the link is visible on the IGP topology, but IGP does not select the link as the optimal route when other links are available. In this way, the device can avoid discarding MPLS packets due to lack of LDP LSP on the optimal route.

LDP-IGP synchronization is not supported for an IS-IS process that belongs to a VPN instance.

If you do not specify any keywords, this command enables LDP-ISIS synchronization for both Level-1 and Level-2.

If you execute this command multiple times, the most recent configuration takes effect. For example, if you execute the mpls ldp sync level-1 command after you execute the mpls ldp sync command, LDP-ISIS synchronization is enabled for Level-1 but disabled for Level-2.

Examples

# Enable LDP-ISIS synchronization for Level-2 of IS-IS process 1.

<Sysname> system-view

[Sysname] isis 1

[Sysname-isis-1] mpls ldp sync level-2

Related commands

display mpls ldp igp sync

igp sync delay

igp sync delay on-restart

mpls ldp igp sync disable

mpls ldp sync (OSPF view/OSPF area view)

Use mpls ldp sync to enable LDP-OSPF synchronization.

Use undo mpls ldp sync to disable LDP-OSPF synchronization.

Syntax

mpls ldp sync

undo mpls ldp sync

Default

LDP-OSPF synchronization is disabled.

Views

OSPF view

OSPF area view

Predefined user roles

network-admin

Usage guidelines

LDP-IGP synchronization is not supported for an OSPF process and its OSPF areas if the OSPF process belongs to a VPN instance.

To enable LDP-OSPF synchronization for an OSPF area, use this command in OSPF area view. To enable LDP-OSPF synchronization for all areas of an OSPF process, use this command in OSPF view.

Examples

# Enable LDP-OSPF synchronization for OSPF process 1.

<Sysname> system-view

[Sysname] ospf 1

[Sysname-ospf-1] mpls ldp sync

Related commands

display mpls ldp igp sync

igp sync delay

igp sync delay on-restart

mpls ldp igp sync disable

mpls ldp transport-address

Use mpls ldp transport-address to specify the LDP IPv4 transport address.

Use undo mpls ldp transport-address to remove the configuration.

Syntax

In interface view:

mpls ldp transport-address { ipv4-address | interface }

undo mpls ldp transport-address { ipv4-address | interface }

In LDP peer view:

mpls ldp transport-address ipv4-address

undo mpls ldp transport-address

Default

In interface view, if the interface belongs to the public network, the LDP IPv4 transport address is the local LSR ID. If the interface belongs to a VPN, the LDP IPv4 transport address is the primary IP address of the interface.

In LDP peer view, the LDP IPv4 transport address is the local LSR ID.

Views

Interface view

LDP peer view

Predefined user roles

network-admin

Parameters

ipv4-address: Specifies the LDP IPv4 transport address.

interface: Uses the IPv4 address of the current interface as the LDP IPv4 transport address.

Usage guidelines

Before two LSRs establish an IPv4 LDP session, they must establish a TCP connection by using the LDP IPv4 transport address.

As a best practice, use the default LDP IPv4 transport address.

If two LSRs have multiple links in between and you want to establish an IPv4 LDP session on each link, make sure all the links use the same IPv4 transport address.

Examples

# Specify the LDP transport address carried in Targeted Hellos sent to peer 3.3.3.3 as 2.2.2.2.

<Sysname> system-view

[Sysname] mpls ldp

[Sysname-ldp] targeted-peer 3.3.3.3

[Sysname-ldp-peer-3.3.3.3] mpls ldp transport-address 2.2.2.2

# On VLAN-interface 2, specify the transport address carried in Link Hellos as the IP address of the interface.

<Sysname> system-view

[Sysname] interface vlan-interface 2

[Sysname-Vlan-interface2] mpls ldp transport-address interface

Related commands

display mpls ldp discovery

targeted-peer

session protection

Use session protection to enable session protection.

Use undo session protection to disable session protection.

Syntax

session protection [ duration time ] [ peer peer-prefix-list-name ]

undo session protection

Default

Session protection is disabled.

Views

LDP view

Predefined user roles

network-admin

Parameters

duration time: Specifies the session protection duration time in the range of 30 to 2147483 seconds. If you do not specify the duration, session protection always takes effect.

peer peer-prefix-list-name: Specifies an IP prefix list by its name, a case-sensitive string of 1 to 63 characters. Sessions to the peers whose LSR IDs are permitted by the specified IP prefix list are protected. If you do not specify this option, all sessions established by the Basic Discovery mechanism are protected.

Usage guidelines

If two LDP peers have both a direct link and an indirect link in between, you can configure this feature to protect their LDP session when the direct link fails.

LDP establishes both a Link Hello adjacency over the direct link and a Targeted Hello adjacency over the indirect link with the peer. When the direct link fails, LDP deletes the Link Hello adjacency but still maintains the Targeted Hello adjacency. In this way, the LDP session between the two peers is kept available, and the FEC-label mappings based on this session are not deleted. When the direct link recovers, the LDP peers do not need to re-establish the LDP session or re-learn the FEC-label mappings.

When you enable the session protection feature, you can specify the session protection duration. If the Link Hello adjacency does not recover within the duration, LDP deletes the Targeted Hello adjacency and the LDP session. If you do not specify the session protection duration, the two peers always maintain the LDP session over the Targeted Hello adjacency.

Examples

# Enable protection for the session to peer 3.3.3.3, and set the session protection duration to 120 seconds.

<Sysname> system-view

[Sysname] ip prefix-list protected-peer-list index 1 permit 3.3.3.3 32

[Sysname] mpls ldp

[Sysname-ldp] session protection duration 120 peer protected-peer-list

Related commands

display mpls ldp peer

targeted-peer

Use targeted-peer to create a targeted IPv4 LDP peer and enter its view, or enter the view of an existing targeted IPv4 LDP peer. The device can send unsolicited IPv4 Targeted Hellos to the peer and can respond to IPv4 Targeted Hellos received from the peer.

Use undo targeted-peer to cancel the configuration.

Syntax

targeted-peer ipv4-address [ peer-name ]

undo targeted-peer ipv4-address

Default

No targeted LDP peers exist. The device does not send IPv4 Targeted Hellos to any peers, or respond to IPv4 Targeted Hellos received from any peers.

Views

LDP view

Predefined user roles

network-admin

Parameters

ipv4-address: Specifies the peer IPv4 address.

peer-name: Specifies a unique name for the targeted peer. If you do not specify this argument, the specified IPv4 address is used as the targeted peer name.

Usage guidelines

If you do not specify the LDP transport address, LDP sends the local LSR ID to the peer specified by this command in IPv4 Targeted Hellos.

To ensure a successful IPv4 Targeted Hello adjacency, make sure the following requirements are met:

· The peer IPv4 address configured on the local LSR is the same as the IPv4 transport address configured in LDP peer view on the peer.

· A route exists between the local IPv4 transport address and the peer IPv4 address.

LDP automatically sends Targeted Hellos to the specified peer after one of the following features is configured:

· LDP session protection.

· MPLS L2VPN LDP PW.

· VPLS LDP PW.

To modify the Targeted Hello/Keepalive hold time and interval, you must use this command to create the LDP peer, and then perform the modification in the LDP peer view.

Examples

# Configure the device to send IPv4 Targeted Hellos to peer 3.3.3.3, and enter LDP peer view.

<Sysname> system-view

[Sysname] mpls ldp

[Sysname-ldp] targeted-peer 3.3.3.3

[Sysname-ldp-peer-3.3.3.3]

Related commands

display mpls ldp discovery

display mpls ldp peer

07-MPLS Command Reference

snmp-agent trap enable ldp

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