Login
- Table of Contents
- Related Documents
-
| Title | Size | Download |
|---|---|---|
| 01-Basic MPLS commands | 131.71 KB |
Basic MPLS commands
The switch operates in IRF or standalone (the default) mode. For more information about IRF, see IRF Configuration Guide.
display mpls forwarding ilm
Use display mpls forwarding ilm to display Incoming Label Map (ILM) entries.
In standalone mode:
display mpls forwarding ilm [ label ] slot slot-number
In IRF mode:
display mpls forwarding ilm [ label ] chassis chassis-number slot slot-number
Views
Any view
Predefined user roles
network-admin
network-operator
mdc-admin
mdc-operator
Parameters
label: Displays the ILM entry with the specified incoming label. The value range for the incoming label is 16 to 1000000. If you do not specify an incoming label, the command displays information about all ILM entries on the specified card.
slot slot-number: Specifies a card by its slot number. (In standalone mode.)
chassis chassis-number slot slot-number: Specifies a card on an IRF member device. The chassis-number argument specifies the ID of the IRF member device, and the slot-number argument specifies the number of the slot that holds the card. (In IRF mode.)
Usage guidelines
An ILM entry records the label operation type, outgoing label, and other forwarding information. After an LSR receives a labeled packet, it identifies the ILM entry that matches the top label of the packet, performs the specified label operation, and forwards the packet.
Examples
# Display the ILM entry with incoming label 30.
<Sysname> display mpls forwarding ilm 30
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
InLabel Oper VRF Flag SwapLabel Forwarding Info
--------------------------------------------------------------------------------
30 SWAP 0 T 1300 1024
# 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
InLabel Oper VRF Flag SwapLabel Forwarding Info
--------------------------------------------------------------------------------
30 SWAP 0 T 1300 1024
1279 POP 0 - - -
1407 SWAP 0 NA 1271 GE3/0/3 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 nexthop IP address. · B—Backup forwarding information. · A—Active forwarding information. |
|
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
In standalone mode:
display mpls forwarding nhlfe [ nid ] slot slot-number
In IRF mode:
display mpls forwarding nhlfe [ nid ] chassis chassis-number slot slot-number
Views
Any view
Predefined user roles
network-admin
network-operator
mdc-admin
mdc-operator
Parameters
nid: Displays the NHLFE entry with the specified NID. The value range for the NID is 0 to 1000000. If you do not specify an NID, the command displays information about all NHLFE entries on the specified card.
slot slot-number: Specifies a card by its slot number. (In standalone mode.)
chassis chassis-number slot slot-number: Specifies a card on an IRF member device. The chassis-number argument specifies the ID of the IRF member device, and the slot-number argument specifies the number of the slot that holds the card. (In IRF mode.)
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 first obtains the bottom label and NID in the matching FIB or ILM entry, and then 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
NID Tnl-Type Flag OutLabel Forwarding Info
--------------------------------------------------------------------------------
2048 LSP NA 2025 GE3/0/2 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
NID Tnl-Type Flag OutLabel Forwarding Info
--------------------------------------------------------------------------------
10 - TA - 2049
20 - TA - 2050
2048 LSP NA 2025 GE3/0/2 10.11.112.26
2049 LSP NA 3024 GE3/0/2 10.11.112.26
TB 3026 20
2050 LSP NA 3025 GE3/0/1 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: LSP, GRE, or CRLSP. If the tunnel type is an invalid value, this field displays a hyphen (-). |
|
Flag |
Forwarding flag: · T—Forwarded through a tunnel. · N—Forwarded through the outgoing interface to the nexthop IP address. · B—Backup forwarding information. · A—Active 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
mdc-admin
mdc-operator
Parameters
interface-type interface-number: Specifies an interface by its type and number. If you do not specify an interface, the command displays MPLS information for all MPLS-enabled interfaces.
Examples
# Displays all MPLS interfaces.
<Sysname> display mpls interface
Interface Status MPLS MTU
GE3/0/1 Up 1514
GE3/0/2 Up 1514
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
mdc-admin
mdc-operator
Parameters
label-value1: Specifies a label in the range of 16 to 1000000. 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 in the range of 16 to 1000000. If you specify a label range by using the label-value1 argument and the to label-value2 option, the command displays usage information for the specified range of labels.
all: Specifies all labels.
Examples
# Display the usage information of labels 900 through 902.
<Sysname> display mpls label 900 to 902
Label Owner State
900 - Idle
901 - Idle
902 LDP Alloc
Table 3 Command output
|
Field |
Description |
|
Label |
Label value. |
|
Owner |
Protocol that is using the label. Possible values include LDP, BGP, RSVP, and L2VPN. |
|
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-dest mask-length | ipv6 [ ipv6-dest prefix-length ] ] [ verbose ]
Views
Any view
Predefined user roles
network-admin
network-operator
mdc-admin
mdc-operator
Parameters
egress: Displays the LSPs taking the current LSR as the egress.
in-label label-value: Displays the LSPs using the specified label as the incoming label. The value range for the label-value argument is 0 to 1000000.
ingress: Displays the LSPs taking the current LSR as the 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 specific protocol.
bgp: Displays BGP LSPs.
Ldp: Displays LDP LSPs.
local: Displays the direct LSP.
rsvp-te: Displays CR-LSPs established by RSVP-TE. The switch does not support this keyword.
static: Displays static LSPs.
static-cr: Displays static CR-LSPs. The switch does not support this keyword.
transit: Displays the LSPs taking the current LSR as a transit LSR.
vpn-instance vpn-instance-name: Displays LSPs for the specified VPN. 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-dest mask-length: Displays the IPv4 LSP for a 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-dest prefix-length: Displays the IPv6 LSP for a 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 no parameters are specified, the command displays brief information for all LSPs. If you specify only the verbose keyword, the command displays detailed information for all LSPs.
Examples
# Display brief information for 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
200.200.200.200/64000/64000 RSVP -/1030 Vlan10
201.200.200.200/64000/64000 RSVP 1024/1031 Vlan10
202.200.200.200/64000/64000 RSVP 1025/- -
150.140.150.100/64001/0 StaticCR -/1000 Vlan10
- StaticCR 50/1001 Vlan10
- StaticCR 51/- -
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, static transit CR-LSP, or static egress CR-LSP. · Backup—If the LSP is a backup LSP of the previous LSP, this field displays "Backup." |
|
Proto |
Label distribution protocol: · LDP. · BGP. · RSVP. · Static. · StaticCR—Static CR-LSP. · Local—The LSP is a direct LSP. |
|
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 : 2050
Out-Label: 10003 Out-Interface: Vlan10
BkLabel : 10004 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. · Ingress LSR ID/Tunnel ID/LSP ID—RSVP TE FEC. · A hyphen (-)—The LSP is a static transit LSP, static egress LSP, static transit CR-LSP, or static egress CR-LSP. |
|
Protocol |
Label distribution protocol: · LDP. · BGP. · RSVP. · Static. · StaticCR—Static CR-LSP. · Local—Direct LSP. |
|
BkLabel |
Outgoing label of the backup LSP. |
|
BkInterface |
Outgoing interface of the backup LSP. |
# Display detailed information for 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
BkInteface : 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. · Ingress LSR ID/Tunnel ID/LSP ID—RSVP TE FEC. · A hyphen (-)—The LSP is a static transit LSP, static egress LSP, static transit CR-LSP, or static egress CR-LSP. |
|
Proto |
Label distribution protocol: · LDP. · BGP. · RSVP. · Static. · StaticCR—Static CR-LSP. · Local—Direct LSP. |
|
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 |
Service deployed on the LSP. |
|
Path ID |
Forwarding path. The value is in the format of 0xnn.m, where 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. |
|
Outgoing NID |
Index of the NHLFE entry for the outer tunnel. |
|
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. |
Related commands
display mpls lsp statistics
display mpls lsp statistics
Use display mpls lsp statistics to display LSP statistics.
Syntax
display mpls lsp statistics
Views
Any view
Predefined user roles
network-admin
network-operator
mdc-admin
mdc-operator
Examples
# Display LSP statistics.
<Sysname> display mpls lsp statistics
LSP Type Ingress/Transit/Egress Active
Static LSP 0/0/0 0/0/0
Static CRLSP 0/0/0 0/0/0
LDP LSP 2/2/1 2/2/1
RSVP CRLSP 0/0/0 0/0/0
BGP LSP 0/0/0 0/0/0
Local LSP 2/0/0 2/0/0
-----------------------------------------------------
Total 4/2/1 4/2/1
Table 7 Command output
|
Field |
Description |
|
LSP Type |
LSP types: · Static LSP. · Static CRLSP. · LDP LSP. · Local LSP (direct LSP). · RSVP CRLSP. · BGP LSP. |
|
Total |
Total number of LSPs. |
|
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. |
|
Active |
Number of active LSPs of a specific type. |
display mpls nid
Use display mpls nid to display the NID usage information.
Syntax
display mpls nid [ nid-value1 [ to nid-value2 ] ]
Views
Any view
Predefined user roles
network-admin
network-operator
mdc-admin
mdc-operator
Parameters
nid-value1: Specifies an NID in the range of 0 to 1000000. 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 in the range of 0 to 1000000. If you specify an NID range by using the nid-value1 argument and the to nid-value2 option, the command displays the usage information for the specified range of NIDs.
Usage guidelines
If you do not specify any parameter, the command displays the usage information of all NIDs.
Examples
# Display the usage information of 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
mdc-admin
mdc-operator
Examples
# Display MPLS summary information.
<Sysname> display mpls summary
Memory State : Normal
MPLS LSR ID : 2.2.2.2
Egress Label Type: Implicit-null
Labels:
Range Idle
16-1023 1008
1024-13311 12288
65536-69631 4096
131072-139263 8192
Protocols:
Type State
BGP Normal
Static Normal
Table 8 Command output
|
Field |
Description |
|
Memory State |
Memory state: · Normal—The memory is normal. · Minor—The memory has a minor alarm. · Severe—The memory has a severe alarm. · Critical—The memory has a critical alarm. |
|
Egress Label Type |
Label type that the egress 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 |
Running label distribution protocols and the related information. |
|
Type |
Protocol type: LDP, BGP, RSVP, Static, Static CRLSP, or TE. |
|
State |
Label distribution protocol running status: · Normal. · Recover—The protocol is in the GR process. |
display mpls statistics
Use display mpls statistics to display MPLS forwarding statistics for each LSP, such as the number of packets processed and dropped in the inbound and outbound directions.
Syntax
display mpls statistics { all | lsp-index index }
Views
Any view
Predefined user roles
network-admin
network-operator
mdc-admin
mdc-operator
Parameters
all: Displays MPLS forwarding statistics for all LSPs.
lsp-index index: Displays MPLS forwarding statistics for the specified LSP. The index argument represents the index of an LSP, in the range of 1 to 4294967295.
Usage guidelines
To use this command to view MPLS forwarding statistics for LSPs, you must first enable MPLS forwarding statistics for LSPs by using the mpls statistics command. Otherwise, the statistics are all 0.
Examples
# Display MPLS forwarding statistics for all LSPs.
<Sysname> display mpls statistics all
Statistics for LSP (LSP index: 9218):
Inbound:
Octets : 0
Packets : 0
Errors : 0
Discards : 0
Start Time : 2006/05/20 15:52:30
End Time : 2006/05/20 15:52:30
Outbound:
Octets : 0
Packets : 0
Errors : 0
Discards : 0
Start Time : 0000/00/00 00:00:00
End Time : 0000/00/00 00:00:00
Statistics for LSP (LSP index: 9219):
Inbound:
Octets : 0
Packets : 0
Errors : 0
Discards : 0
Start Time : 0000/00/00 00:00:00
End Time : 0000/00/00 00:00:00
Outbound:
Octets : 0
Packets : 0
Errors : 0
Discards : 0
Start Time : 2006/05/20 15:52:30
End Time : 2006/05/20 15:52:30
Table 9 Command output
|
Field |
Description |
|
Statistics for LSP (LSP index: index) |
MPLS forwarding statistics for the LSP identified by the index. |
|
Inbound |
Inbound direction. |
|
Outbound |
Outbound direction. |
|
Octets |
Bytes of packets processed. |
|
Packets |
Number of packets processed. |
|
Errors |
Number of errors. |
|
Discards |
Number of packets discarded. |
|
Start Time |
Start time of the statistics. |
|
End Time |
End time of the statistics. |
|
|
NOTE: · On an ingress node, no statistics are collected in the inbound direction and the start time and end time for inbound statistics are both 0. · On an egress node, no statistics are collected in the outbound direction and the start time and end time for outbound statistics are both 0. |
Related commands
mpls statistics
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
mdc-admin
Usage guidelines
Execute this command on all interfaces that need to perform MPLS forwarding.
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 will advertise to the penultimate hop.
Use undo mpls label advertise to restore the default.
Syntax
mpls label advertise { explicit-null | implicit-null }
undo mpls label advertise
Default
As an egress, the device advertises an implicit null label to the penultimate hop.
Views
System view
Predefined user roles
network-admin
mdc-admin
Parameters
explicit-null: Specifies the egress to advertise an explicit null label of 0 to the penultimate hop.
implicit-null: Specifies the egress to advertise an implicit null label of 3 to the penultimate hop.
Usage guidelines
If the penultimate hop supports PHP, H3C recommends that you configure the egress to advertise an implicit null label to the penultimate hop. If you want to simplify packet forwarding on the egress but keep labels in packets for the egress to determine QoS policies, you can configure the egress to advertise an explicit null label to the penultimate hop.
As a penultimate hop, the device allows the egress to advertise to the penultimate hop an implicit null label or an explicit null label.
The mpls label advertise command takes effect only for the LSPs established after the command is executed. To apply the new setting to LSPs established before the command is executed, delete and then re-establish those LSPs:
· To re-establish LDP LSPs, execute the reset mpls ldp command to reset the LDP session.
· To re-establish BGP LSPs, delete the routes corresponding to the BGP LSPs, and then redistribute the routes.
Examples
# Configure the egress device to advertise an explicit null label to the penultimate hop.
<Sysname> system-view
[Sysname] mpls label advertise explicit-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 delete the LSR ID of the local LSR.
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
mdc-admin
Parameters
lsr-id: Specifies an ID for identifying the LSR, in dotted decimal notation.
Usage guidelines
H3C recommends that you 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 configure the MPLS MTU for an interface.
Use undo mpls mtu to restore the default.
Syntax
mpls mtu value
undo mpls mtu
Default
The MPLS MTU of an interface is not configured. Fragmentation for MPLS packets is based on the MTU of the interface, and the length of a fragment does not include that of the MPLS label. Thus, after an MPLS label is inserted into a fragment, the length of the MPLS fragment may exceed the interface MTU.
Views
Interface view
Predefined user roles
network-admin
mdc-admin
Parameters
value: 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 may fail.
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 of MPLS TTL-expired messages.
Use undo mpls ttl expiration enable to disable the function.
Syntax
mpls ttl expiration enable
undo mpls ttl expiration enable
Default
The MPLS TTL-expired messages sending function is enabled.
Views
System view
Predefined user roles
network-admin
mdc-admin
Usage guidelines
The mpls ttl expiration enable 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, which then sends the message back to the source.
Examples
# Disable the MPLS TTL-expired messages sending function.
<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 disabled for VPN packets.
Views
System view
Predefined user roles
network-admin
mdc-admin
Parameters
public: Specifies public network packets.
vpn: Specifies VPN packets.
Usage guidelines
When TTL propagation is enabled, MPLS copies the IP TTL to the label TTL for packets entering the MPLS network, and copies the label TTL to the IP TTL for packets leaving the MPLS network. If you enable TTL propagation on both the ingress and egress, the IP tracert facility can show the real path in the MPLS network.
When TTL propagation is disabled, MPLS sets the label TTL to 255 for packets entering the MPLS network, and 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.
H3C recommends setting 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, so that you can get the same traceroute result (hop count) from those PEs.
Examples
# Enable TTL propagation for VPN packets.
<Sysname> system-view
[Sysname] mpls ttl propagate vpn
