H3C S9500 Series Operating instructions

Brand: H3C

Model: S9500 Series

Type: Operating instructions

H3C S9500 Series is designed to maximize your network's performance and availability through advanced capabilities such as MPLS OAM (Operations, Administration, and Maintenance), which provides comprehensive monitoring and troubleshooting of MPLS networks by detecting and reporting link and path defects, enabling rapid service restoration and ensuring high service quality.

Operation Manual – MPLS OAM

H3C S9500 Series Routing Switches Table of Contents

Table of Contents

Chapter 1 MPLS OAM Configuration...........................................................................................1-1

1.1 MPLS OAM Overview........................................................................................................1-1

1.1.1 MPLS OAM Background.........................................................................................1-1

1.1.2 MPLS OAM Packet Types and Formats.................................................................1-2

1.1.3 MPLS OAM Capabilities..........................................................................................1-5

1.1.4 References..............................................................................................................1-7

1.2 MPLS OAM Configuration .................................................................................................1-7

1.2.1 MPLS OAM Configuration Task List .......................................................................1-7

1.2.2 Configuring MPLS OAM Basic Capability...............................................................1-7

1.2.3 Configuring a Protection Group...............................................................................1-9

1.3 Displaying and Debugging MPLS OAM Basic Capability................................................1-10

1.4 Typical MPLS OAM Configuration Example....................................................................1-11

1.5 Troubleshooting MPLS OAM...........................................................................................1-16

1.5.1 Failure to Enable OAM on the Ingress Node........................................................1-16

1.5.2 Failure to Enable OAM on the Egress Node.........................................................1-16

1.5.3 Abnormal Verification Occurs on the Egress Node...............................................1-17

1.5.4 The Defect State of the Ingress Node is Different from that of the Egress Node..........1-17

1.5.5 The Defects of the Ingress Node cannot Trigger Protection Switching................1-18

1.5.6 The Primary LSP Recovered from a Defect, but the Protection Group cannot Switch

back................................................................................................................................

1-19

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Chapter 1 MPLS OAM Configuration

When configuring MPLS OAM, go to these sections for information you are interested

in:

z MPLS OAM Overview

z MPLS OAM Configuration

z Displaying and Debugging MPLS OAM Basic Capability

z Typical MPLS OAM Configuration Example

z Troubleshooting MPLS OAM

 Note:

Currently the H3C S9500 series routing switches do not support the FFD.

1.1 MPLS OAM Overview

Operation, administration and maintenance (OAM) is a tool designed for monitoring

and troubleshooting network problems. It provides an effective way of reducing network

maintenance costs. MPLS OAM is intended for the operation, administration and

maintenance on the MPLS layer.

1.1.1 MPLS OAM Background

MPLS supports multiple Layer 2 and Layer 3 protocols like IP, ATM, and Ethernet. To

enable the following features on the user plane of MPLS, MPLS needs to provide an

OAM mechanism fully independent of any upper layer or lower layer:

z LSP connectivity.

z Protection switching so that services can be provided in compliance with the

service level agreements (SLAs) signed with customers in the presence of link

defects (or failures).

With this MPLS OAM mechanism employed, you can effectively pinpoint defects in an

MPLS network, report defects and take corresponding measures, and provide a

triggering mechanism for protection switching in case of failures.

For detailed information about MPLS OAM background, refer to ITU-T

Recommendation Y.1710.

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1.1.2 MPLS OAM Packet Types and Formats

MPLS OAM packets fall into four types: connectivity verification (CV), fast failure

detection (FFD), forward defect indication (FDI) and backward defect indication (BDI).

The following sections present a description of their formats.

I. OAM CV packets

The LSP connectivity is verified by checking that the egress node of an LSP has

received the OAM CV packets sent from the ingress node.

Figure 1-1 shows the format

of the OAM CV packet.

Padding (all 00Hex)

(18 octets)

BIP16 (2 octets)

Function type (01Hex) Reserved (all 00Hex)

LSP Trail Termination Source Identifier

(20 octets)

07 31

Figure 1-1 OAM CV packet format

Table 1-1 describes the fields of the OAM CV packet.

Table 1-1 Description on the fields of the OAM CV packet

Field Description

Function type Packet type, with 0x01 being the CV packet

Reserved Reserved field

LSP Trail

Termination Source

Identifier

TTSI, uniquely identifying an LSP in a network. It consists of

16-byte ingress LSR ID and 4-byte LSP ID. For IPv4, the first

10 bytes of ingress LSR ID are padded with 0x00, the

following two bytes are padded with 0xFF, and the last four

bytes are IPv4 address.

Padding Padded field

BIP16 Packet checksum

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II. OAM FFD packets

Like CV packets, you also can verify the LSP connectivity by checking the OAM FFD

packets sent from the ingress node of an LSP arrive at the egress node.

Figure 1-2

shows the format of the OAM FFD packet.

Compared with a CV packet, a FFD packet has additional 1-byte frequency information.

The transmission frequency is set to 1 second for the CV packet. For the FFD packet,

multiple transmission frequencies are supported, including 10ms, 20ms, 50ms, 100ms,

200ms, and 500ms.

Padding (all 00Hex)

(17 octets)

BIP16 (2 octets)

Function type (07Hex) Reserved (all 00Hex)

LSP Trail Termination Source Identifier

(20 octets)

07 31

Frequency

Figure 1-2 OAM FFD packet format.

Table 1-2 describes the fields of the OAM FFD packet.

Table 1-2 Description on the fields of the OAM FFD packet

Field Description

Function type

Packet type, with 0x07 being the FFD

packet

Reserved Reserved field

LSP Trail Termination Source Identifier TTSI. Refer to Table 1-1.

Frequency Transmission frequency for FFD packet

Padding Padded field

BIP16 Packet checksum

III. OAM FDI packets

OAM FDI packets are used by the upstream node of an LSP to notify the egress node of

defect information. In addition, when auto protocol is enabled, the ingress node notifies

the egress node with OAM FDI packets that it should stop defect verification.

Figure 1-3

shows the format of the OAM FDI packet.

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Padding (all 00Hex)

(14 octets)

BIP16 (2 octets)

Function type (02Hex) Reserved (00Hex)

TTSI (optional, if not used set to all 00Hex)

(20 octets)

07 31

Defect location (4 octets)

Defect type

Figure 1-3 OAM FDI packet format

Table 1-3 describes the fields of the OAM FDI packet.

Table 1-3 Description on the fields of the OAM FDI packet

Field Description

Function type Packet type, with 0x02 being the FDI packet

Reserved Reserved field

Defect type Type of LSP defects

TTSI

LSP identifier, refer to

Table 1-1. Without TTSI, each byte of the

field is padded with 0x00.

Defect location Information about defect location

Padding Padded field

BIP16 Packet checksum

IV. OAM BDI packets

OAM BDI packets are used by the egress node to notify the ingress node of defect

information through a reverse channel after it finds LSP defects.

Figure 1-4 shows the

format of the OAM BDI packet.

The implications of the fields of the OAM BDI packet are the same as that of the OAM

FDI packet, as shown in Table 5-3.

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Padding (all 00Hex)

(14 octets)

BIP16 (2 octets)

Function type (03Hex) Reserved (00Hex)

TTSI (optional, if not used set to all 00Hex)

(20 octets)

07 31

Defect location (4 octets)

Defect type

Figure 1-4 OAM BDI packet format

1.1.3 MPLS OAM Capabilities

I. Basic capability

MPLS OAM basic capability refers to connectivity verification.

Ingress

Egress

LSR

Ingress

Egress

LSR

Figure 1-5 Networking diagram for MPLS OAM connectivity verification

As shown in

Figure 1-5, procedure of connectivity verification follows:

1) The ingress node sends CV/FFD packets through the LSP to be verified to the

egress node.

2) By comparing the received information such as packet type, frequency and TTSI

with the locally recorded values that should be received, the egress node checks

the packets are received properly, and takes statistics for the right packets and

wrong packets received in the verification period so as to monitor the LSP

connectivity.

3) Once it detects LSP defects, the egress node analyzes the types of LSP defects

and transmits the BDI packet with defect information to the ingress node through a

reverse channel. In this way, the ingress node can get the defect state

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immediately. If a protection group is configured properly, the corresponding

protection switching would also be triggered.

When configuring MPLS OAM basic capability, you need to bind a reverse channel to

the LSP to be verified. A reverse channel is an LSP which has an ingress node and an

egress node contrary to the LSP to be verified. There are two types of reverse

channels:

z Dedicated reverse channel: Each forward LSP has its own reverse channel. This

means is rather stable but may incur wasted resources.

z Shared reverse channel: Multiple forward LSPs have a reverse channel in

common. All the LSPs transmit BDI packets through this LSP. This means

reduces wasted resources. However, the shared reverse channel may be

congested when defects are detected on multiple forward LSPs at the same time.

Configuring additional acknowledgement information for BDI packets is required in

order for the ingress node to distinguish which forward LSP has defects depending

on the BDI packets received. For example, TTSI is configured for the MPLS OAM.

As a result, a BDI packet can carry the TTSI information of the LSP to be verified,

which is useful for checking the BDI packet is necessary.

II. Protection switching

Protection switching (PS) is designed to establish the corresponding protection LSP

(secondary LSP) for the primary LSP. The primary LSP and the secondary LSP

constitute a protection group. In protection switching mode, once the primary LSP fails,

data flows can be switched to the secondary LSP rapidly, significantly improving the

reliability of networks.

In real world, you also can manually input some switching commands as required to

switch from the primary LSP to the secondary LSP, or vice versa. Manual switching and

signaling switching are prioritized. For manual switching, the switching takes effect only

when its priority is higher than the priority of the current signaling.

For PS, four modes are supported: 1:1 protection, 1+1 protection, share mesh

protection and packet 1+1 protection.

z 1:1 protection: Two LSPs in primary/secondary mode are available between the

ingress node and the egress node. In general, data is transported over the primary

LSP; when the ingress node detects some defect on the primary LSP through

verification mechanism (for example, OAM) and needs to run protection switching,

it switches data to the secondary LSP and keeps on transmission.

z 1+1 protection: Two LSPs in primary/secondary mode are available between the

ingress node and the egress node. In general, the ingress node sends the same

data packets to these two LSPs at the same time; but the egress node only

receives the data from the primary LSP. When the egress node detects some

defect on the primary LSP, it stops receiving data from the primary LSP and

switches to the secondary LSP to receive data.

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z Share mesh protection: This protection mode is designed for saving bandwidth in

the mesh network topology. In short, an LSP is used as the secondary LSP for

multiple LSPs. When any LSP fails, data packets to be transported over the LSP

are switched to the secondary LSP. The triggering and switching mechanisms of

this mode are similar to 1:1 protection.

z Packet 1+1 protection: This protection mode is similar to 1+1 protection. The

difference between them is that for packet 1+1 protection, the ingress node sends

packets with order labels through the primary LSP and the secondary LSP to the

egress node. For the packets with the same order label, the egress node receives

the one arrived in advance and drops the other. This protection mode is rather

complex and difficult to control.

Now, only 1:1 protection is supported.

1.1.4 References

For more information about MPLS OAM, refer to:

z ITU-T Recommendation Y.1710: Requirements for Operation & Maintenance

functionality for MPLS networks

z ITU-T Recommendation Y.1711: Operation & Maintenance mechanism for MPLS

networks

z ITU-T Recommendation Y.1720: Protection switching for MPLS networks

1.2 MPLS OAM Configuration

1.2.1 MPLS OAM Configuration Task List

Task Remarks

Configuring MPLS OAM Basic Capability Required

Configuring a Protection Group Required

1.2.2 Configuring MPLS OAM Basic Capability

I. Configuration Prerequisites

1) Application environment

MPLS OAM basic verification capability is designed to monitor the connectivity state of

an MPLS network, and verify and pinpoint the defects in the MPLS network. To verify

the connectivity of the MPLS network, you should configure the MPLS OAM function for

LSPs.

2) Configuration preparation

To configure MPLS OAM basic capability, perform the following tasks:

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z Configure MPLS basic capabilities, refer to MPLS Configuration.

z Configure static LSPs, refer to MPLS Configuration.

3) Data preparation

To configure MPLS OAM basic capability, prepare the following data:

Table 1-4 Data preparation

Number Data

1 The static LSP to be verified

For ingress node, LSP ID of the static LSP to be verified

For egress node, the ingress LSR ID and LSP ID of the static LSP to

be verified

3 The static LSP of the reverse channel

MPLS OAM parameters, for instance, verification packet type and

FFD transmission frequency

If the ingress node adopts a shared reverse channel, the No. 3 data in the above table

is omitted.

II. Configuration Procedure

Follow these steps to configure MPLS OAM basic capability:

To do... Use the command... Remarks

Enter system view

system-view

—

Enable MPLS OAM

mpls oam

Required

Configure MPLS OAM

parameters for the

ingress node

mpls oam ingress lsp-name

lsp-name lsp-id lsp-id [ type { cv | ffd

[ frequency ffd-fre ] } ] [ backward-lsp

share | lsp-name rev-lsp-name ]

Required

Enable OAM for the

ingress node

mpls oam ingress enable { all |

lsp-name lsp-name }

Required

Configure MPLS OAM

parameters for the

egress node

mpls oam egress lsp-name

lsp-name lsr-id lsr-id lsp-id lsp-id

[ type { cv | ffd [ frequency ffd-fre ] } ]

[ backward-lsp rev-lsp-name [ private

| share ] ]

Required

Enable OAM for the

egress node

mpls oam egress enable { all |

lsp-name lsp-name }

Required

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 Note:

z This operation also can be used for modifying MPLS OAM parameters.

z The configuration of MPLS OAM parameters takes effect only after the MPLS OAM

function is enabled. You must first enable the MPLS OAM function on the ingress

node and then on the egress node. Otherwise, the egress node will generate an

alert.

1.2.3 Configuring a Protection Group

I. Configuration Prerequisites

1) Application environment

In an environment with higher demand on network performance, a protection channel is

reserved so that transmission of data flows can be restored rapidly after the primary

LSP failed.

2) Configuration preparation

To configure a protection group, perform the following tasks:

z Enable MPLS;

z Create the primary static LSP and the secondary static LSP.

3) Data preparation

To configure a protection group, prepare the following data:

Table 1-5 Data preparation

Number Data

1 Protection group ID

2 Name of the primary LSP in the protection group

3 Name of the secondary LSP in the protection group

Protection group parameters, for instance, Hold off time, switch

back mode and WTR time

Note that:

1) This operation also can be used for modifying protection group parameters.

2) Switch back means that after the primary LSP recovered from a fault, data flows

are switched from the secondary LSP back to the primary LSP.

3) FIB entries are not updated when data flows are switched from the primary LSP to

the secondary LSP. By querying the primary and secondary LSPs and the

protection group, you can view the forwarding information of the current LSP (for

instance, next hop, outbounding interface).

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4) The data flow is on the primary LSP if both the primary and secondary LSPs in one

protection group fail.

z When the primary LSP is in the up/no-defect state and the secondary LSP is in the

down, in-defect, or down/in-defect state, the data flow is on the primary LSP. If the

primary LSP then turns into the down, in-defect, or down/in-defect state, no

switching will take place.

z When the primary LSP is in the down, in-defect or down/in-defect state and the

secondary LSP is in the up/no-defect state, the data flow is on the secondary LSP.

If the secondary LSP then turns into the down, in-defect, or down/in-defect state,

the data flow will be switched to the primary LSP though the latter is not

operational.

5) When you delete a protection group where the data flow is on the secondary LSP,

the data flow will be switched to the primary LSP before the group is deleted, even

if the primary LSP is not operational.

6) If no protection group is configured, the manually-configured secondary LSP will

not have a corresponding LSP forwarding entry.

II. Configuration Procedure

Follow these steps to configure a protection group:

To do... Use the command... Remarks

Enter system view

system-view

—

Configure a protection

group for the specified

primary LSP

mpls protect-switch protect-id

work-lsp lsp-name protect-lsp

lsp-name [ holdoff holdoff-time ]

[ mode revertive ] [ wtr wtr-time ]

mpls protect-switch protect-id

work-lsp lsp-name protect-lsp

lsp-name [ holdoff holdoff-time ]

mode non-revertive

Required

Enable external protection

switch

mpls protect-switch manual

{ protect-lsp | work-lsp } protect-id

Optional

Display information about

the protection group

display mpls protect-switch { all |

protect-id } [ verbose | brief ]

In any view

1.3 Displaying and Debugging MPLS OAM Basic Capability

To do… Use the command... Remarks

Display MPLS OAM

information on the ingress

node

display mpls oam ingress { all |

lsp-name lsp-name } [ slot slot-id |

verbose ]

Alailable in

any view

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To do… Use the command... Remarks

Display MPLS OAM

information on the egress

node

display mpls oam egress { all |

lsp-name lsp-name } [ slot slot-id |

verbose ]

Alailable in

any view

Display information about

OAM packets received on

the ingress node

display mpls oam ingress

receive-packet { all | bdi | error } slot

slot-id

Alailable in

any view

Display information about

OAM packets sent from

the ingress node

display mpls oam ingress

send-packet { all | ap-fdi | cv | error |

ffd } slot slot-id

Alailable in

any view

Display information about

OAM packets received on

the egress node

display mpls oam egress

receive-packet { all | ap-fdi | cv |

error | fdi | ffd } slot slot-id

Alailable in

any view

Display information about

OAM packets sent from

the egress node

display mpls oam egress

send-packet { all | bdi | error } slot

slot-id

Alailable in

any view

Clear the statistics of all

OAM packets on the

ingress node

reset mpls oam packet-statistics

ingress { all | lsp-name lsp-name }

Alailable in

user view

Clear the statistics of all

OAM packets on the

egress node

reset mpls oam packet-statistics

egress { all | lsp-name lsp-name }

Alailable in

user view

Clear the statistics of

OAM packets for the

specified interface card

reset mpls oam packet-statistics

slot slot-id

Alailable in

user view

Executing the above mentioned commands, you will view the following results:

z Basic LSP information, including LSP name, LSP state, ingress LSR ID;

z Basic OAM information, including LSP name, TTSI, verification packet type,

transmission frequency;

z OAM verification information, including type of the packets to be transmitted,

transmission period, verification state and defect state. When the LSP works

properly, the verification state is Start and the defect state is No-defect;

z OAM reverse channel information, including share type, configuration information;

z Statistics of OAM packets received/sent on the ingress node;

z Statistics of OAM packets received/sent on the egress node.

1.4 Typical MPLS OAM Configuration Example

I. Network requirements

As shown in Figure 1-6, two static LSPs (in primary/secondary mode) and a shared

reverse channel are available between Switch A and Switch B. Once it detects

connectivity defects on the primary LSP, the egress node Switch C notifies the ingress

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node Switch A of defect verification results, and switches data flows to the secondary

LSP.

In this case, only Switch A and Switch C need to support MPLS OAM, Switch B, Switch

D and Switch E do not.

1) Configuration preparation

z At least two static LSPs are available between the ingress node and the egress

node to constitute a protection group. At the same time, a reverse static LSP from

the egress node to the ingress node is available for the egress node to notify

connectivity defects.

z You need to configure a protection group, and specify the protection group ID,

protection switching delay, switch back mode and switch back wait time.

z You need to enable MPLS OAM globally on the ingress node and the egress node.

z You need to configure MPLS OAM parameters for the LSP to be verified and

enable the MPLS OAM function on the ingress node.

z You need to configure MPLS OAM parameters for the LSP to be verified and

enable the MPLS OAM function on the egress node

2) Data preparation

To complete the configuration, you need to specify the following data:

z IP addresses of VLAN interfaces of various switches and names of various static

LSPs, as shown in Figure 5-6.

z Static LSPs borrow the loopback addresses of various switches. The destination

IP address of the primary and secondary LSPs is 3.3.3.3/32 and the destination IP

address of the reverse channel is 1.1.1.1/32.

z In a protection group, the switch back delay is set to 10, that is, 1 second; the

switch back mode is revertive; the switch back wait time is 20, that is, 10 minutes.

z The type of verification packet to be sent is set to CV and the transmission period

is the defaulted 1 second.

z The reverse channel is set to share.

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II. Networking diagram

Loopback0

4.4.4.4/32

Loopback0

VLAN34

Loopback0

1.1.1.1/32

SwitchA

VLAN14

VLAN12

VLAN15

15.1.1.1/24

VLAN15

LspAtCp

2.2.2.2/32

Loopback0

5.5.5.5/32

VLAN34

34.1.1.1/24

Loopback0

3.3.3.3/32

VLAN23 VLAN23

VLAN53

53.1.1.1/24

VLAN53

53.1.1.1/24

23.1.1.1/24

23.1.1.2/24

Switch D

Switch E

Switch B

SwitchC

VLAN14

14.1.1.2/24

14.1.1.1/24

VLAN12

12.1.1.1/24

12.1.1.2/24

15.1.1.2/24

Lspid:200

LspAtCw

Lspid:100

LspCtA

Figure 1-6 Networking diagram for configuring OAM and PS basic capabilities

III. Configuration procedure

1) Configure IP addresses for various interfaces

As shown in

Figure 1-6, configure the IP addresses and masks of various interfaces,

including various loopback interfaces. The detailed configuration steps are omitted.

2) Configure the IGP protocol

Enable OSPF on all switches and advertise their own routes. The detailed configuration

steps are omitted.

After the above configurations are completed, switches should interoperate to each

other on the network layer. You can issue the display ip routing-table command on

switches to view the routing table.

3) Configure MPLS OAM and static LSPs

As shown in

Figure 1-6, configure the primary static LSP LspAtC and the secondary

static LSP LspAtCp on Switch A; configure a shared reverse channel LspCtA on Switch

4) Configure MPLS OAM for Switch A

# Enable MPLS OAM globally.

<SwitchA> system-view

[SwitchA] mpls oam

# Configure OAM parameters for the ingress node.

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[SwitchA] mpls oam ingress lsp-name LspAtCw lsp-id 100

[SwitchA] mpls oam ingress lsp-name LspAtCp lsp-id 200

# Configure a protection group.

[SwitchA] mpls protect-switch 1 work-lsp lspAtCw protect-lsp lspAtCp holdoff

10 mode revertive wtr 20

Using the display mpls protect-switch all command, you will see the following

information:

[SwitchA] display mpls protect-switch all

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

Protection-Switching Information

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

PROTECT-ID Dft-W Dft-P Ctrl-W Ctrl-P SwitchRst

1 No-defect No-defect Up Up W

# Enable MPLS OAM on the ingress node.

[SwitchA] mpls oam ingress enable all

5) Configure MPLS OAM for Switch C

# Enable MPLS OAM globally.

<SwitchC> system-view

[SwitchC] mpls oam

# Configure OAM parameters for the egress node.

[SwitchC] mpls oam egress lsp-name lspAtCw lsr-id 1.1.1.1 lsp-id 100

backward-lsp lspCtA share

[SwitchC] mpls oam egress enable lsp-name lspAtCw

[SwitchC] mpls oam egress lsp-name lspAtCp lsr-id 1.1.1.1 lsp-id 200

backward-lsp lspCtA share

[SwitchC] mpls oam egress enable lsp-name lspAtCp

After completing the above configurations, you can view information about the current

LSP and OAM and statistics of OAM verification packets on Switch A and Switch C.

The following takes the display on Switch C as an example.

# Display configuration information about the current LSP and OAM.

<SwitchC> display mpls oam egress all verbose

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

Verbose information about the 1st OAM at egress

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

lsp basic information: oam basic information:

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

Lsp-name : lspAtCw Oam-Index : 1024

Lsp signal status : Up Oam select board : 2

Lsp incoming Label : 3 Enable-state : --

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Lsp ingress lsr-id : 1.1.1.1 Auto-protocol :Disable

Auto-overtime (s) : 0

Ttsi/lsr-id : 1.1.1.1

Ttsi/lsp-id : 100

oam detect information: oam backward information:

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

Type : CV Share attribute : Share

Frequency : 1 s Lsp-name : lspCtA

Detect-state : Start Lsp-state : Up

Defect-state : No-defect

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

Verbose information about the 2nd OAM at egress

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

lsp basic information: oam basic information:

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

Lsp-name : lspAtCp Oam-Index : 1025

Lsp signal status : Up Oam select board : 2

Lsp incoming Label : 3 Enable-state : --

Lsp ingress lsr-id : 1.1.1.1 Auto-protocol : Disable

Auto-overtime (s) : 0

Ttsi/lsr-id : 1.1.1.1

Ttsi/lsp-id : 200

oam detect information: oam backward information:

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

Type : CV Share attribute : Share

Frequency : 1 s Lsp-name : lspCtA

Detect-state : Start Lsp-state : Up

Defect-state : No-

efect

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

Total Oam Num: 2

Total Start Oam Num: 2

Total Defect Oam Num: 0

# Display the statistics of verification packets received on the egress node.

<SwitchC> display mpls oam egress receive-packet all slot 2

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

CV Packet FFD Packet FDI Packet AP-FDI Packet Error Packet

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

467 0 0 0 0

6) Verify the configuration

Shutdown interface VLAN12 of Switch B. At this point, the primary LSP on Switch A

detects a defect.

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1-16

Using the display mpls protect-switch all command on Switch A, you will see that

data flows are switched to the secondary LSP.

[SwitchA] display mpls protect-switch all

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

Protection-Switching Information

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

PROTECT-ID Dft-W Dft-P Ctrl-W Ctrl-P SwitchRst

1 Defect No-defect Up Up P

1.5 Troubleshooting MPLS OAM

1.5.1 Failure to Enable OAM on the Ingress Node

I. Symptom

When you execute the mpls oam ingress enable [ lsp-name lsp-name ] command on

the ingress node, the message “% Warning: Invalid LSP name.” displays.

II. Solution

According to the message, you will see that the OAM parameters for the ingress node

are not configured rightly. To solve the problem, you can:

z Execute the mpls oam ingress lsp-name lsp-name lsp-id lsp-id [ type { cv | ffd

[ frequency ffd-fre ] } ] [ backward-lsp share | lsp-name rev-lsp-name ]

command on the ingress node to configure OAM parameters for the LSP to be

verified.

z Execute the display mpls oam ingress [ all | lsp lsp-name ] command to display

the configured OAM parameters.

z Execute the mpls oam ingress enable [ all | lsp-name lsp-name ] command to

enable the MPLS OAM function.

1.5.2 Failure to Enable OAM on the Egress Node

I. Symptom

When you execute the mpls oam egress enable [ lspname lsp-name ] command on

the egress node, the message “% Warning: Invalid LSP name.” displays.

II. Solution

According to the message, you will see that the OAM parameters for the egress node

are not configured rightly. To solve the problem, you can:

z Execute the mpls oam egress lsp-name lsp-name lsr-id ingress-lsr-id lsp-id

lsp-id } type { cv | ffd [ frequency ffd-fre ] } ] [ backward-lsp rev-lsp-name

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[ private | share ] ] command on the egress node to configure OAM parameters

for the LSP to be verified.

z Execute the display mpls oam egress [ all | lspname lsp-name ] command to

display OAM parameters configured in step 1.

z Execute the mpls oam egress enable [ all | lsp-name lsp-name ] command to

enable the MPLS OAM function.

1.5.3 Abnormal Verification Occurs on the Egress Node

I. Symptom

The network works properly. When you execute the display mpls oam egress [ all |

lspname lsp-name ] verbose command on the egress node, the defect-sate field

displays dLocv or dUnknown.

II. Solution

The reason for this problem may come from:

z The ingress node does not enable OAM.

z The ingress LSR ID and LSP ID of the LSP to be verified are not configured rightly

on the ingress node and the egress node.

z OAM parameters like verification packet type and transmission frequency

configured on the ingress node and the egress node are not consistent.

To solve this problem, you can:

z When you execute the display mpls oam ingress [ all | lsp-name lsp-name ]

verbose command, the Enable-state field displays Manual disable, meaning that

the ingress node does not enable OAM. In this case, you should execute the mpls

oam ingress enable [ all | lsp-name lsp-name ] command to enable OAM on the

ingress node.

z If OAM is enabled on the ingress node, execute the display mpls oam ingress

[ all | lsp-name lsp-name ] verbose command and the display mpls oam egress

[ all | lspname lsp-name ] verbose command to display the OAM configuration for

the ingress node and the egress node respectively. If the ingress LSR ID and LSP

ID of the LSP to be verified, verification packet type and transmission frequency

are inconsistent, use the corresponding configuration command to configure them

properly and reenable OAM.

1.5.4 The Defect State of the Ingress Node is Different from that of the Egress

Node

I. Symptom

When you execute the display mpls oam egress [ all | lsp-name lsp-name ] verbose

command on the egress node, the Defect-sate field displays dLocv; while you execute

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H3C S9500 Series Routing Switches Chapter 1 MPLS OAM Configuration

1-18

the display mpls oam ingress [ all | lsp-name lsp-name ] verbose command on the

ingress node, the defect-sate field displays No-defect.

II. Solution

The reason for this problem may come from:

z The reverse channel is not configured or down. So the egress node cannot notify

the ingress node of defect verification results.

z The reverse channel specified by the ingress node is different from that specified

by the egress node.

To solve this problem, you can:

z Execute the display mpls oam egress [ all | lsp-name lsp-name ] verbose

command. If the lsp-name field is null in the oam backward information, which

means the reverse channel is not configured. In this case, you should use the

OAM configuration command to configure a reverse channel for the LSP to be

verified.

z Both nodes are configured with a reverse channel, but the lsp-state field is down in

the oam backward information. In this case, you should modify MPLS

configuration and make the reverse channel up, or reuse OAM configuration

commands to configure an up reverse channel for the LSP to be verified.

z The reverse channel of the egress node is up, but it is different from that

configured on the ingress node. In this case, you should configure the reverse

channel properly on the egress node and the ingress node.

1.5.5 The Defects of the Ingress Node cannot Trigger Protection Switching

I. Symptom

Protection switching is enabled. When you execute the display mpls oam ingress [ all

| lsp-name lsp-name ] verbose on the ingress node, the defect-state field displays In

defect; while you execute the display mpls protect-switch [ protect-id | all ] verbose

command through command line, the Switching Result field displays Working LSP.

II. Solution

The reason for this problem may come from:

z The primary LSP is not the one for OAM defect verification.

z The secondary LSP also has defects and data flows are not switched.

z Holdoff is not zero. You need to wait a period of time before triggering protection

switching.

z External switching command restricts the transmission of data flows to the primary

LSP.

To solve this problem, you can:

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1-19

z Execute the display mpls protect-switch [ all | protect-id ] verbose command. If

the Working LSP User Plane Status is No-defect, which means the primary LSP

configured in the protection group is not the one for OAM defect verification. In this

case, you should use OAM ingress node and egress node configuration

commands to configure OAM parameters for the primary LSP in the protection

group and restart defect verification, or use the protection group configuration

command to configure a protection group for the LSP for defect verification.

z If the Working LSP User Plane Status field is In defect and the Protect LSP User

Plane Status field is In defect, which means the secondary LSP in the protection

group has defects. In this case, you should use the protection group command to

configure another perfect LSP and the primary LSP to constitute a protection

group.

z If the above two conditions are not met, view the Holdoff field. If the Holdoff is not

zero, which means Holdoff does not expire. This is not a fault. When the primary

LSP fails, data flows are switched to the secondary LSP only when it is always

available after Holdoff time. To trigger protection switching immediately after the

primary LSP fails, you should use the protection group command to set Holdoff to

zero.

1.5.6 The Primary LSP Recovered from a Defect, but the Protection Group

cannot Switch back

I. Symptom

When you execute the display mpls protect-switch protect-id command, the Switch

Rst field is P. In this case, data flows are still transmitted over the secondary LSP, even

the primary LSP recovered from a defect.

II. Solution

The reason for this problem may come from:

z The protection group is in non-revertive mode.

z The switch back wait time is longer.

z The external switching command switches data flows to the secondary LSP for

transmission by force. It has a higher priority.

To solve this problem, you can:

z Execute the display mpls protect-switch [ protect-id | all ] verbose command. If

the Revertive Mode field is Non-revertive, the protection group is in non-revertive

mode. This is not a fault. To trigger switch back after the primary LSP recovered

from a defect, you should use the mpls protect-switch command to configure the

protection group as revertive mode.

z If the protection group is in revertive mode and the WTR field is not zero, which

means WTR does not expire. This is not a fault. After the primary LSP recovered

from a defect, data flows will be switched back to the primary LSP in WTR time. To

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H3C S9500 Series Operating instructions

H3C S9500 Series Operating instructions

H3C S9500 Series Operating instructions

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