troubleshooting - layer 2 network(v600r003c00_02)

HUAWEI NetEngine80E/40E RouterV600R003C00

Troubleshooting - Layer 2 Network

Issue 02

Date 2011-09-10

HUAWEI TECHNOLOGIES CO., LTD.

Copyright © Huawei Technologies Co., Ltd. 2011. All rights reserved.No part of this document may be reproduced or transmitted in any form or by any means without prior writtenconsent of Huawei Technologies Co., Ltd. Trademarks and Permissions

and other Huawei trademarks are trademarks of Huawei Technologies Co., Ltd.All other trademarks and trade names mentioned in this document are the property of their respective holders. NoticeThe purchased products, services and features are stipulated by the contract made between Huawei and thecustomer. All or part of the products, services and features described in this document may not be within thepurchase scope or the usage scope. Unless otherwise specified in the contract, all statements, information,and recommendations in this document are provided "AS IS" without warranties, guarantees or representationsof any kind, either express or implied.

The information in this document is subject to change without notice. Every effort has been made in thepreparation of this document to ensure accuracy of the contents, but all statements, information, andrecommendations in this document do not constitute the warranty of any kind, express or implied.

Huawei Technologies Co., Ltd.Address: Huawei Industrial Base

Bantian, LonggangShenzhen 518129People's Republic of China

Website: http://www.huawei.com

Email: [email protected]

Issue 02 (2011-09-10) Huawei Proprietary and ConfidentialCopyright © Huawei Technologies Co., Ltd.

i

http://www.huawei.com

mailto:[email protected]

About This Document

PurposeNOTE

l This document takes interface numbers and link types of the NE40E-X8 as an example. In workingsituations, the actual interface numbers and link types may be different from those used in thisdocument.

l On NE80E/40E series excluding NE40E-X1 and NE40E-X2, line processing boards are called LineProcessing Units (LPUs) and switching fabric boards are called Switching Fabric Units (SFUs). Onthe NE40E-X1 and NE40E-X2, there are no LPUs and SFUs, and NPUs implement the same functionsof LPUs and SFUs to exchange and forward packets.

This document describes how to troubleshoot the services of the HUAWEI NetEngine80E/40E in terms of common faults and causes, troubleshooting cases, and FAQs.

This document describes the procedure and method for troubleshooting for the HUAWEINetEngine80E/40E.

Related VersionsThe following table lists the product versions related to this document.

Product Name Version

HUAWEI NetEngine80E/40ERouter

V600R003C00

Intended AudienceThis document is intended for:

l System maintenance engineers

l Commissioning engineers

l Network monitoring engineers

HUAWEI NetEngine80E/40E RouterTroubleshooting - Layer 2 Network About This Document


ii

Symbol ConventionsThe symbols that may be found in this document are defined as follows.

Symbol Description

DANGERIndicates a hazard with a high level of risk, which if notavoided, will result in death or serious injury.

WARNINGIndicates a hazard with a medium or low level of risk, whichif not avoided, could result in minor or moderate injury.

CAUTIONIndicates a potentially hazardous situation, which if notavoided, could result in equipment damage, data loss,performance degradation, or unexpected results.

TIP Indicates a tip that may help you solve a problem or savetime.

NOTE Provides additional information to emphasize or supplementimportant points of the main text.

Command ConventionsThe command conventions that may be found in this document are defined as follows.

Convention Description

Boldface The keywords of a command line are in boldface.

Italic Command arguments are in italics.

[ ] Items (keywords or arguments) in brackets [ ] are optional.

{ x | y | ... } Optional items are grouped in braces and separated byvertical bars. One item is selected.

[ x | y | ... ] Optional items are grouped in brackets and separated byvertical bars. One item is selected or no item is selected.

{ x | y | ... }* Optional items are grouped in braces and separated byvertical bars. A minimum of one item or a maximum of allitems can be selected.

[ x | y | ... ]* Optional items are grouped in brackets and separated byvertical bars. Several items or no item can be selected.

&<1-n> The parameter before the & sign can be repeated 1 to n times.

# A line starting with the # sign is comments.



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Change HistoryChanges between document issues are cumulative. The latest document issue contains all thechanges made in earlier issues.

Changes in Issue 02 (2011-09-10)The second commercial release. There is no update compared with the previous issue.

Changes in Issue 01 (2011-05-30)Initial field trial release.



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Contents

About This Document.....................................................................................................................ii

1 QinQ Troubleshooting.................................................................................................................11.1 Related Troubleshooting Cases..........................................................................................................................2

1.1.1 Non-Huawei Devices Cannot Ping the User Gateway Address Configured on the BRAS Attached to therouter...................................................................................................................................................................21.1.2 Some DHCP Clients Cannot Obtain IP Addresses from the DHCP Server When the DHCP Relay AgentIs Configured with a Sub-Interface for Dot1q VLAN Tag Termination............................................................61.1.3 Network Segments Cannot Successfully Ping Each Other In Dot1q Termination Access.......................7

2 HGMP Troubleshooting............................................................................................................102.1 A Candidate Switch Directly Connected to the Administrator Switch Cannot Be Added to the Cluster........11

2.1.1 Common Causes......................................................................................................................................112.1.2 Troubleshooting Flowchart......................................................................................................................112.1.3 Troubleshooting Procedure......................................................................................................................132.1.4 Relevant Alarms and Logs......................................................................................................................16

3 Ethernet OAM Troubleshooting..............................................................................................183.1 Ethernet OAM 802.1ag Trace Fails..................................................................................................................19


4 MSTP Troubleshooting..............................................................................................................234.1 MSTP Topology Change Leads to Service Interruption..................................................................................24


5 RRPP Troubleshooting...............................................................................................................315.1 RRPP Loop Occurs Temporarily......................................................................................................................32


HUAWEI NetEngine80E/40E RouterTroubleshooting - Layer 2 Network Contents


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6 PPP Troubleshooting..................................................................................................................356.1 Protocol Status of a PPP Interface Is Down.....................................................................................................36


6.2 Related Troubleshooting Cases........................................................................................................................416.2.1 Half of Packets Are Discarded the First Minute After an MP-Group Link Fails....................................426.2.2 Incorrect Configurations of Member Interfaces Cause the MP-group Link to Work Unstably..............43

6.3 ATM Troubleshooting......................................................................................................................................456.4 The Ping Fails on Both Ends of an ATM Network..........................................................................................45


6.5 Troubleshooting Cases.....................................................................................................................................476.5.1 OSPF Neighbor Relationship Cannot Be Set Up Between P2P ATM Sub-interfaces............................47

HUAWEI NetEngine80E/40E RouterTroubleshooting - Layer 2 Network Contents


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1 QinQ Troubleshooting

About This Chapter

1.1 Related Troubleshooting Cases

HUAWEI NetEngine80E/40E RouterTroubleshooting - Layer 2 Network 1 QinQ Troubleshooting


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1.1.1 Non-Huawei Devices Cannot Ping the User Gateway AddressConfigured on the BRAS Attached to the router

Users are connected to non-Huawei devices through the BRAS and the router. User can configurea sub-interface for dot1q VLAN tag termination on the router to run unicast routing protocols.vid specified in the control-vid command must be the same as vid specified in the dot1qtermination vid command. Otherwise, non-Huawei devices cannot ping the user gatewayaddress configured on the BRAS attached to the router.

Fault SymptomOn the network shown in Figure 1-1, a CE accesses an external network through the BRAS,PE, and NPEs. After ACL rules and a routing protocol on a sub-interface for dot1q VLAN tagtermination are configured on the PE, the PE can successfully ping the user gateway address ofthe BRAS; the PE can successfully ping the user gateway address of the BRAS by using theaddress of the interface connecting to an NPE as the source address; none of the NPEs can pingthe user gateway address of the BRAS.

NOTE

The PE is Huawei device; NPEs are non-Huawei devices.



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Figure 1-1 Networking diagram

CE

BRAS

PE

NPE1

VLAN4000

Gateway address1.1.1.1/30

GE1/0/22.1.1.1/30

GE1/0/1.12.1.1.2/30

GE1/0/24.4.4.4/24 GE1/0/5

NPE2 NPE3

NPE4

GE1/0/1

MPLS/IPCore

GE1/0/4GE1/0/3

Data flow

Fault Analysis1. After using an NPE to ping the address of the upstream interface GE 1/0/2 on the BRAS

and the user gateway address of the BRAS by using the external network address as thesource address, do as follows:l Run the display interface command on each of the four upstream interfaces of the PE.

The command output shows that each upstream interface has received ping packets andforwarded the packets through the downstream interface GE 1/0/1. Take the display onthe upstream interface GE 1/0/2 of the PE as an example.<PE> display interface gigabitethernet 1/0/2GigabitEthernet1/0/2 current state : UPLine protocol current state : UPLast line protocol up time : 2010-05-31 11:57:21 UTC-08:00



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Description:HUAWEI, GigabitEthernet1/0/2 InterfaceRoute Port,The Maximum Transmit Unit is 1500Internet Address is 4.4.4.4/24IP Sending Frames' Format is PKTFMT_ETHNT_2, Hardware address is 00e0-5c5e-8600QoS max-bandwidth : 1000000 KbpsOutput queue : (Urgent queue : Size/Length/Discards) 0/50/0Output queue : (Protocol queue : Size/Length/Discards) 0/1000/0Output queue : (FIFO queue : Size/Length/Discards) 0/256/0

Last physical up time : 2010-05-31 11:57:20 UTC-08:00Last physical down time : 2010-05-31 11:53:57 UTC-08:00Current system time: 2010-05-31 12:05:46-08:00Hardware address is 00e0-5c5e-8600 Last 300 seconds input rate 0 bytes/sec, 0 packets/sec Last 300 seconds output rate 2 bytes/sec, 0 packets/sec Input: 2768 bytes, 31 packets Output: 4134 bytes, 46 packets Input: Unicast: 16 packets, Multicast: 15 packets Broadcast: 0 Output: Unicast: 14 packets, Multicast: 31 packets Broadcast: 1 packets

Input bandwidth utilization : 0.00 Output bandwidth utilization : 0.00

Take the display on the downstream interface GE 1/0/1 of the PE as an example.<PE> display interface gigabitethernet 1/0/1GigabitEthernet1/0/1 current state : UPLine protocol current state : DOWNDescription:HUAWEI, GigabitEthernet1/0/1 InterfaceRoute Port,The Maximum Transmit Unit is 1500Internet protocol processing : disabledIP Sending Frames' Format is PKTFMT_ETHNT_2, Hardware address is 00e0-7b2c-8200QoS max-bandwidth : 1000000 KbpsOutput queue : (Urgent queue : Size/Length/Discards) 0/50/0Output queue : (Protocol queue : Size/Length/Discards) 0/1000/0Output queue : (FIFO queue : Size/Length/Discards) 0/256/0

Last physical up time : 2010-05-31 14:18:20 UTC-08:00Last physical down time : 2010-05-31 13:47:43 UTC-08:00Current system time: 2010-05-31 14:23:27-08:00Hardware address is 00e0-7b2c-8200 Last 300 seconds input rate 2 bytes/sec, 0 packets/sec Last 300 seconds output rate 0 bytes/sec, 0 packets/sec Input: 2854 bytes, 32 packets Output: 4008 bytes, 45 packets Input: Unicast: 15 packets, Multicast: 16 packets Broadcast: 1 Output: Unicast: 15 packets, Multicast: 30 packets Broadcast: 0 packets

Input bandwidth utilization : 0.00 Output bandwidth utilization : 0.00

In the command output, Input indicates the total number of packets and bytes receivedon the interface; Output indicates the total number of packets and bytes sent by theinterface.

l Run the display acl command on the PE. The command output shows that ping packetscan match ACL rules on upstream interfaces of the PE but are directly discarded on thedownstream interface GE 1/0/1. Therefore, it can be concluded that the PE is the failurepoint.



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<PE> display acl 3100Advanced ACL 3100, 5 rules rule 5 permit icmp source 4.4.4.4 0 destination 1.1.1.1 0 (2 times matched) rule 10 permit icmp source 1.1.1.1 0 destination 4.4.4.4 0 (0 times matched) rule 15 permit icmp source 4.4.4.4 0 destination 2.1.1.1 0 (0 times matched) rule 20 permit icmp destination 2.1.1.1 0 (31 times matched) rule 25 permit icmp destination 1.1.1.1 0 (20 times matched)traffic classifier icmp operator or if-match acl 3100traffic behavior icmptraffic policy icmp statistics enable classifier icmp behavior icmp

2. Run the display this command on the downstream interface GE 1/0/1 of the PE to viewthe configuration of the interface.<PE> display thisinterface GigabitEthernet1/0/1.1 control-vid 1 dot1q-termination dot1q termination vid 4000 ip address 2.1.1.2 255.255.255.252 traffic-policy icmp outbound arp broadcast enable trust upstream default trust 8021pThe command output shows that vid specified in the control-vid command is different fromvid specified in the dot1q termination vid command. After the two VLAN IDs are set tothe same value, every NPE can ping the user gateway address of the BRAS successfully,and the fault is cleared.

ProcedureStep 1 Run the system-view command to enter the system view.

Re-configure the sub-interface for dot1q VLAN tag termination of the PE to ensure that thecontrol VLAN ID is the same as the user VLAN ID terminated by the sub-interface.

Step 2 Run the interface interface-type interface-number.subinterface-number command to enter theview of the Ethernet sub-interface on the AC side of the PE.

Step 3 Run the control-vid vid dot1q-termination rt-protocol command to configure the Ethernetsub-interface as a sub-interface for dot1q VLAN tag termination and set the control VLAN IDof the sub-interface.

NOTE

vid specified in the control-vid command must be the same as vid specified in the dot1q terminationvid command.

Step 4 Run the return command to return to the user view, and then run the save command to save themodification.

After the preceding configurations, every NPE can ping the user gateway address of the BRASsuccessfully. The fault is cleared.

----End

SummaryIn the case of a sub-interface for dot1q VLAN tag termination that runs routing protocols, youneed to ensure that the control VLAN ID configured for the sub-interface is the same as the user



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VLAN ID terminated by the sub-interface. In addition, you are recommended to use the control-vid command with the parameter rt-protocol. In this manner, the system will prompt a messagewhen the control VLAN ID is different from the user VLAN ID terminated by the sub-interface.

If the parameter rt-protocol is not configured, the system does not prompt any message whenthe control VLAN ID is different from the user VLAN ID terminated by the sub-interface.

1.1.2 Some DHCP Clients Cannot Obtain IP Addresses from theDHCP Server When the DHCP Relay Agent Is Configured with aSub-Interface for Dot1q VLAN Tag Termination

After the DHCP relay agent is configured to terminate packets from multiple VLANs throughthe same sub-interface, some DHCP clients cannot obtain IP addresses from the DHCP server.

Fault SymptomIn the networking shown in Figure 1-2, Router Afunctions as the DHCP server; Router Bfunctions as the DHCP relay agent. A PC, that is, a DHCP client, is connected to Router Bthrough Switch A. After the configuration, the DHCP client cannot obtain an IP address fromthe DHCP server.

Figure 1-2 Networking for a DHCP client to obtain an IP address from the DHCP server

DHCP Clients

DHCP Server

DHCP RelayRouterB

RouterA

PC

SwitchAGE1/0/1.100

VLAN10 VLAN20 VLAN30

Fault Analysis1. Assign an IP address from the address pool to the PC. Ping the gateway address of Router

B from the PC. The ping is successful, indicating that the Layer 2 network runs properly.



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Capture packets on the PC. The PC succeeds in sending a DHCPDISCOVER message butfails to receive a DHCPOFFER message.

2. Ping the IP address of Router A from Router B. The ping is successful.3. Capture packets transmitted between Router B and Switch A through port mirroring. A

DHCPOFFER message has been sent from Router B to Switch A.4. Analyze the DHCPOFFER message sent from Router B. When the sub-interface for Dot1q

VLAN tag termination sends the DHCPOFFER message to the PC, Router B adds only theVLAN tag with the smallest VLAN ID of the sub-interface for Dot1q VLAN tag terminationto the DHCPOFFER message. In this example, the Router B adds only VLAN 10, shownin Figure 1-2, to the DHCPOFFER message. The PC, however, belongs to VLAN 20.Therefore, the DHCPOFFER message is discarded by Switch A.The Option field in a DHCP message is used to carry control information and parametersthat are not defined in common protocols. If you require that the Option field carry theVLAN ID of a tagged packet sent from a client, you can enable the Option 82 function onthe DHCP relay agent.

ProcedureStep 1 Run the system-view command to enter the system view.

Step 2 Run the interface { ethernet | gigabitethernet } interface-number.subinterface-numbercommand to enter the Ethernet sub-interface view.

Step 3 Run the dhcp option82 insert enable command to enable Option 82 insertion for DHCPmessages on the sub-interface.

After the preceding operations are completed, the PC can obtain an IP address from the DHCPserver. The fault is thus rectified.

----End

SummaryThe Option 82 field is a DHCP Relay Agent Information option recording the locationinformation of a DHCP client. It is a special field contained in a DHCP message.

The DHCP relay agent appends the Option 82 field to a DHCPDISCOVER message sent froma client to the server. Upon receipt of the DHCPDISCOVER message that carries the Option 82field, the DHCP server responds to the DHCP relay agent with a DHCPOFFER message thatcontains the same Option 82 field. The DHCP relay agent then determines to where theDHCPOFFER message is destined based on the Option 82 field carried in the message.

1.1.3 Network Segments Cannot Successfully Ping Each Other InDot1q Termination Access

Fault SymptomIn the networking shown in Figure 1-3, users on the network segment A access the router throughthe BAS; users on the network segment B access the router through the sub-interface for Dot1qVLAN tag termination on the router. After ping operations are performed between networksegment A and network segment B, it is found that some addresses cannot successfully pingeach other. The router, however, can successfully ping both network segment A and networksegment B.



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Figure 1-3 Networking for network segments failing to ping each other in Dot1q terminationaccess

User Network A

User Network B

GE1/0/0.1

GE2/0/0.1

BAS Router

Switch

Switch

GE1/0/0.2

GE2/0/0.2

Fault Analysis1. Run the display this command in the view of sub-interfaces of GE 1/0/0 on the router to

view information about the sub-interfaces of GE 1/0/0. The information is displayed asfollows:#interface GigabitEthernet1/0/0.1 control-vid 10 dot1q-termination dot1q termination vid 3 ip address 10.1.1.1 255.255.255.0 arp broadcast enable#interface GigabitEthernet1/0/0.2 undo shutdown vlan-type dot1q 10 ip address 10.1.1.2 255.255.255.0#

2. Run the display this command in the view of sub-interfaces of GE 2/0/0 on the router toview information about the sub-interfaces of GE 2/0/0. The information is displayed asfollows:#interface GigabitEthernet2/0/0.1 undo shutdown vlan-type dot1q 10 ip address 10.2.1.1 255.255.255.0#interface GigabitEthernet2/0/0.2 undo shutdown vlan-type dot1q 10 ip address 10.2.1.2 255.255.255.0#

3. You can find that GE 1/0/0.1 is configured as the sub-interface for Dot1q VLAN tagtermination, whereas other sub-interfaces are configured to terminate VLAN packetsthrough the vlan-type dot1q command. If a user needs to access the router through a sub-interface for Dot1q VLAN tag termination and also supports network segment routes, it isrequired that rt-protocol be configured and the configured user VLAN ID be the same as



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the control VLAN ID. In this case, you can change the configuration of GE 1/0/0.1 to rectifythe fault.

Procedure

Step 1 Run the system-view command to enter the system view.

Step 2 Run the interface interface-type interface-number command to enter the sub-interface view.

Step 3 Run the control-vid vid dot1q-termination rt-protocol command to configure the controlVLAN for the sub-interface for Dot1q VLAN tag termination.

NOTE

If rt-protocol is configured when configuring the control VLAN, ensure that the user VLAN ID is thesame as the control VLAN ID when running the dot1q termination vid command.

Step 4 Run the vlan-group group-id command to configure a user VLAN group.

Step 5 Run the statistic enable command to enable the QinQ statistics function for the user VLANgroup on the sub-interface.

Step 6 Run the quit command to return to the sub-interface view.

Step 7 Run the dot1q termination vid low-pe-vid vlan-group group-id command to configure the sub-interface for Dot1q VLAN tag termination.

After the preceding operations, network segment A and network segment B can successfullyping each other.

----End

SummaryNetwork segment A is connected to the router through the BAS. Therefore, the router cansuccessfully ping network segment A. The router is directly connected to network segment B atLayer 2. Therefore, the router can successfully ping network segment B.

Some addresses on network segment A and network segment B cannot successfully ping eachother due to incorrect Dot1q termination configurations of a sub-interface on the router. If a userneeds to access the router through a sub-interface for Dot1q VLAN tag termination and alsosupports network segment routes, it is required that rt-protocol be configured and the configureduser VLAN ID be the same as the control VLAN ID.



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2 HGMP Troubleshooting

About This Chapter

2.1 A Candidate Switch Directly Connected to the Administrator Switch Cannot Be Added tothe Cluster

HUAWEI NetEngine80E/40E RouterTroubleshooting - Layer 2 Network 2 HGMP Troubleshooting


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2.1 A Candidate Switch Directly Connected to theAdministrator Switch Cannot Be Added to the Cluster

2.1.1 Common CausesTwo switches are directly connected. A cluster is created on one switch. The other switch, thatis, a candidate switch, cannot be added to the cluster, and there is no prompt on the administratorswitch.

This fault is commonly caused by one of the following:

l Packets cannot be exchanged between the administrator switch and candidate switchbecause either of the interfaces connecting them is Down.

l The basic configuration of layer 2 forwarding is incorrectly configured.l Layer 2 packet forwarding or transparent transmission of packets fails.l Packets cannot be exchanged between the administrator switch and candidate switch

because either of the interfaces that the packets pass through is blocked by a ring protocol.l The cluster, NDP, or NTDP is incorrectly configured.l The candidate switch has been added to the cluster and still remains in the cluster, and the

new cluster to which the candidate switch is added has a different name from the currentcluster.

l Authentication of the candidate switch fails due to inconsistent super passwords of thecandidate switch and administrator switch.

2.1.2 Troubleshooting Flowchart

Figure 2-1 shows the troubleshooting flowchart.



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Figure 2-1 Troubleshooting flowchart for the fault that a candidate switch directly connectedto the administrator switch cannot be added to the cluster

A candidate switch directly connected to the

administrator switch cannot be added to the cluster

Change basic configurations

Fault rectified?

Seek technical support

Collect debugging information on the

switches

Disable and then enable cluster on the switch

No

YesNo Yes

Change NDP configurations

No

Fault rectified?Yes

Yes

Change NTDP configurations

Fault rectified?

No

Yes

No

No

Change cluster configurations

No

Fault rectified?YesNo

Yes

Yes

Collect NDP debugging information

No

Yes

Collect NTDP debugging information

No

No

Yes

Yes

Modify the configurations of the Layer 2 loop

protocols

No

Fault rectified?No Yes

Basic configurations correct?

Layer 2 Loop protocols block the

interface running HGMP?

NDPconfigurations correct?

NTDPconfigurations correct?

Cluster configurations correct?

NDP can discovery neighbors?

NTDP can discover topologies?

Switch canbe added to the new

cluster?

Yes

End

End



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2.1.3 Troubleshooting ProcedureNOTE

Saving the results of each troubleshooting step is recommended. If your troubleshooting fails to correctthe fault, you will have a record of your actions to provide Huawei technical support personnel.

Procedure

Step 1 Check that basic configurations of the administrator and candidate switches are correct.

HGMP packets can be exchanged only when Layer 2 forwarding is normal. You need to ensurethat the administrator and candidate switches are correctly configured so that they can exchangeLayer 2 packets.

Ensure that the two switches are configured as follows:

l The two directly connected interfaces are added to the same VLAN.l The VLAN is the cluster management VLAN, which is specified by running the

mngvlanid vlan-id command in the cluster view. In addition, vlan-id specifies the VLANto which the interfaces belong.

l The two interfaces are added to the VLAN in the same manner. For example, the porttrunk allow-pass vlan vlan-id command is run on both interfaces with vlan-id being thesame.

If the preceding configurations are correct, run the display vlan vlan-id command on both theadministrator and candidate switches to check whether interfaces in the VLAN are Up. Forexample,

[HUAWEI] display vlan 1000VLAN ID Type Status MAC Learning----------------------------------------------------------1000 common enable enable----------------Tagged Port: GigabitEthernet1/0/1----------------Interface PhysicalGigabitEthernet1/0/1 UPl If the interfaces are Down, the physical link may fail. In this case, rectify the physical link

fault.l If the interfaces are Up, Layer 2 protocol is normal. In the case where the fault still persists,

either cluster configurations or packet processing at layers above Layer 2 may be incorrect.Go to Step 2.

Step 2 Check that the Layer 2 ring protocols on the interfaces of administrator and candidate switchesrun normally.l If STP is enabled on administrator and candidate switches, check whether the interfaces

running HGMP protocol are blocked by STP. Run the display stp brief command to checkthe interface status. For example,[HUAWEI] display stp brief MSTID Port Role STP State Protection 0 GigabitEthernet1/0/1 ROOT FORWARDING NONE 0 GigabitEthernet1/0/2 DESI FORWARDING NONE 0 GigabitEthernet1/0/3 DESI FORWARDING NONEIf the packets can be normally forwarded, the "STP state" field is displayed asFORWARDING on the interfaces running HGMP protocol. If the "STP state" field isdisplayed as DISCARDING, it indicates that the interface is blocked by STP so that the



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interface cannot forward HGMP packets. You need to change the STP priority so that theinterface can leave the DISCARDING state and the switch can be elected as the root bridge.by running the stp priority priority-level command in the system view. priority-levelranges from 0 to 61440. The smaller the value, the higher the priority. The device with alower STP priority is elected as the root bridge of the ring.If the interfaces running HGMP protocol are in the FORWARDING state, it indicates thatSTP on the interfaces runs normally.

l If RRPP is configured on both administrator and candidate switches, check whether theinterfaces running HGMP protocol are blocked by RRPP. Run the display rrpp verbosedomain domain-index command to check the interface status. For example,[HUAWEI] display rrpp verbose domain 1Domain Index : 1Control VLAN : major 1000 sub 1001Protected VLAN : Reference Instance 1Hello Timer : 1 sec(default is 1 sec) Fail Timer : 6 sec(default is 6 sec)

RRPP Ring : 1Ring Level : 0Node Mode : MasterRing State : FailedIs Enabled : Enable Is Actived : YesPrimary port : GigabitEthernet1/0/3 Port status: UPSecondary port : GigabitEthernet1/0/4 Port status: DOWN

If the "Port status" field is displayed as BLOCK, it indicates that cluster packets on theinterfaces running HGMP protocol are blocked by RRPP. RRPP blocks secondary portsonly. You need to change the blocked interface to be a non-secondary ports to ensure thatthe interface leave the blocked state.If the interfaces running HGMP protocol are in the Upstatus, it indicates that RRPP on theinterfaces runs normally. Go to Step 3.

NOTE

Only one ring protocol, in general, is configured on an interface. Check which ring protocol isconfigured on the interface before checking the interface status.

Step 3 Check that basic NDP functions are normal.

Run the display ndp command on both the administrator and candidate switches to checkwhether NDP can successfully discover neighbors. If NDP can discover neighbors, informationabout the directly connected neighbors can be displayed. For example,

<HUAWEI> display ndp Neighbor discovery protocol is enabled. Neighbor Discovery Protocol Ver: 1, Hello Timer: 60(s), Aging Timer: 180(s) Interface: GigabitEthernet1/0/2 Status: Enabled, Packets Sent: 114, Packets Received: 108, Packets Error: 0 Neighbor 1: Aging Time: 174(s) MAC Address : 0018-8203-39d8 Port Name : GigabitEthernet1/0/1 Software Version: NE40E Version V600R003C00SPC300 Device Name : NE40E Port Duplex : FULL Product Ver : NE40E

If NDP cannot discover neighbors, check that NDP is configured as follows:

l NDP is globally enabled on both switches by running the ndp enable command in the systemview.

l NDP is enabled on the two directly connected interfaces by running the ndp enable commandin the interface view.



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CAUTIONDebugging affects the performance of the system. So, after debugging, run the undo debuggingall command to disable it immediately.

If the NDP configurations are correct whereas NDP still cannot discover neighbors, collect thedebugging information displayed by running the following commands and then contact Huaweitechnical support personnel.

l Run the terminal monitor and terminal debugging commands in the user view to enablemonitoring debugging.

l Run the debugging ndp packet interface interface-type interface-number command in theuser view to enable NDP debugging and collect the debugging information in three minutes.

If NDP can discover neighbors, go to Step 4.

Step 4 Check that basic NTDP functions are normal.

Check that NTDP is configured as follows:

l NTDP is globally enabled on both switches by running the ntdp enable command in thesystem view.

l NTDP is enabled on the two directly connected interfaces by running the ntdp enablecommand in the interface view.

l The cluster management VLAN is configured in the cluster view by running themngvlanid vlan-id command in the cluster view. In addition, vlan-id specifies the VLAN towhich the interface belongs.

If the NTDP configurations are incorrect, correctly configure NTDP.

If the NTDP configurations are correct, run the ntdp explore command on the administratorand candidate switches to discover topologies. After five seconds, run the display ntdp device-list command on the two switches to check whether NTDP can discover topologies. If NTDPcan discover topologies, information about neighbors can be displayed. For example,

[HUAWEI] display ntdp device-listThe device-list of NTDP:------------------------------------------------------------------------------ MAC HOP IP PLATFORM

------------------------------------------------------------------------------ 001c-2334-2312 1 1.1.1.2/24 NE80E/40E 0018-82af-fc38 0 1.1.1.1/24 NE80E/40E

If NTDP cannot discover topologies, collect the debugging information displayed by runningthe following commands on the two switches and then contact Huawei technical supportpersonnel.


l Run the debugging ntdp all command in the use view to enable NTDP debugging.l Run the ntdp explore command to discover topologies and the display ntdp device-list

command to display the topologies.

If NTDP discovers topologies, go to Step 5.



15

NOTE

l A switch can be added to the cluster only if it has been discovered by NTDP on the administrator switch.l Switches do not forward received NDP packets and therefore ring protocols cannot block NDP packets.

NTDP packets are forwarded after being received and therefore NTDP packets may be blocked by ringprotocols.

Step 5 Check that the basic cluster function is normal.

Check whether the cluster function is configured as follows:

l The cluster function is globally enabled on both switches by running the cluster enablecommand in the system view.

l VLANIF interfaces of the cluster management VLAN are configured on both switches byrunning the interface vlanif vlan-id command in the system view. vlan-id must be the sameas that in the mngvlanid command configured in the cluster view.

l An available IP pool is configured on the administrator switch by running the ip-pooladministrator-ip-address mask command in the cluster view.

l The IP addresses manually assigned to the VLANIF interfaces of the management VLANdo not reside in the IP pool configured by using the ip-pool command.

l No super password or the same super password is configured for the administrator andcandidate switches.

If the cluster configurations are incorrect, correctly configure the cluster function.

If the cluster configurations are correct, disable cluster from the switch by running the undocluster enable command, and then run the cluster enable command to ensure that the switchdoes not belong to any cluster. Then, delete the cluster on the administrator switch, and thencreate a new cluster. Check whether the candidate switch can be added to the new cluster.

l Run the undo build command in the cluster view to delete the existing cluster.l Run the auto-build command to create a new cluster.

If the candidate switch still cannot be added to the cluster, collect the debugging informationdisplayed by running the following commands on the two switches and then contact Huaweitechnical support personnel.


l Run the debugging cluster all command in the use view to enable cluster debugging.l Manually add the candidate switch to the cluster by running the add-member mac-

address mac-address command in the cluster view and collect the command output displayedin 10 seconds.

Step 6 Collect the following information and contact Huawei technical support personnel.l Results of the preceding troubleshooting procedurel Configuration files, log files, and alarm files of the device

----End

2.1.4 Relevant Alarms and Logs

Relevant AlarmsHGMP/4/ClstMemStusChg:OID:[oid],DeviceID:[string], Role:[integer].



16

Relevant LogsNone.



17

3 Ethernet OAM Troubleshooting

About This Chapter

3.1 Ethernet OAM 802.1ag Trace Fails

HUAWEI NetEngine80E/40E RouterTroubleshooting - Layer 2 Network 3 Ethernet OAM Troubleshooting


18

3.1 Ethernet OAM 802.1ag Trace Fails

3.1.1 Common CausesOn the network shown in Figure 3-1, Router A fails to perform the 802.1ag MAC trace operationto trace Router C.

[RouterA-md-one-ma-one] trace mac-8021ag mac 0018-823c-c449Tracing the route to 0018-823c-c449 over a maximum of 64 hops:Request timed out.

Figure 3-1 Troubleshooting flowchart for the fault that Ethernet OAM 802.1ag trace fails

RouterA RouterB RouterC

GE8/0/13

GE2/0/10

GE1/0/10

GE1/0/13

This fault is commonly caused by one of the following:l Devices on the traced link run Ethernet OAM 802.1ag of different versions.l A MEP configured on Router C (the traced node) is at a level different from that on Router

A (the trace-initiating node).l A MEP on an intermediate node has the same level as or higher level than that on Router

A.l An intermediate node has no MAC address entry of Router C.



19

3.1.2 Troubleshooting Flowchart

Figure 3-2 Troubleshooting flowchart for the fault that Ethernet OAM 802.1ag trace fails

802.1ag of the same version

is run on Router A, Router B, and

Router C?

A higher-level MEP is configured on

Router C?

A higher-level MEP is configured on

Router B?

Router B has a MAC address entry of

Router C?

Collect information

Change the 802.1ag version to be the same

Configure a MEP on Router B at the same level as the MEP on

Router A

Perform 802.1ag MAC ping on Router A to ping Router C and

allow Router B to learn the MAC address

Configure a MEP on Router C at the same level as the MEP on

Router A

802.1ag trace fails

Yes

Yes

No

Seek techincal support

Yes

No

End

No

Is fault rectified?

Is fault rectified?

Is fault rectified?

Is fault rectified?

Yes

No

Yes

Yes

Yes

Yes

No

No

No

No

3.1.3 Troubleshooting Procedure

Procedure

Step 1 Run the display oam global configuration command to check that only 802.1ag Draft 7 or onlyStandard 802.1ag-2007 is run on all devices along the traced link.



20

l If only 802.1ag Draft 7 or only Standard 802.1ag-2007 is run on all devices along the tracedlink, go to Step 2.

l If 802.1ag Draft 7 and Standard 802.1ag-2007 are run on different devices along the tracedlink, run the cfm version command to change all devices to run only 802.1ag Draft 7 or onlyStandard 802.1ag-2007.

– If Router A successfully performs the MAC trace operation to trace Router C, go to Step6.

– If Router A fails to perform the MAC trace operation to trace Router C, go to Step 2.

Step 2 Run the display this command to check that the MEP configured on Router C has the same levelas the MEP configured on Router A.

l If so, go to Step 3.

l If not, run the cfm md command to set the MEP level on Router C the same as that on RouterA.



Step 3 Run the display cfm mep command to check that the level of the MEP on an intermediate nodeis the same as or higher than that on Router A.

NOTEAfter 802.1ag packets in a lower-level MD enter a higher-level MD, the 802.1ag packets will be discarded;802.1ag packets in a higher-level MD can successfully travel through a lower-level MD. 802.1ag packets in anMD of a specified level cannot travel through the MD with the same level.

l If the level of the MEP on an intermediate node is lower than that on Router A, go to Step4.

l If the level of the MEP on an intermediate node is the same as or higher than that on RouterA, run the cfm md command to set the level of the MEP on the intermediate node to be lowerthan that on Router A.



Step 4 Run the display mac-address dynamic unit unit-id command on each intermediate node tocheck that the MAC address entry of Router C exists.

l If so, go to Step 5.

l If not, run the ping mac-8021ag command to allow the intermediate node to learn the MACaddress of Router C.



Step 5 If the fault persists, contact Huawei technical support personnel.

----End



21


Relevant AlarmsEOAM1AG/4/CCFAULTALARM:OID 1.3.6.1.4.1.2011.5.25.136.1.6.1 MEP is disconnected or reconnected with one or more MEPs. (CfmMdIndex=[GAUGE], CfmMaIndex=[GAUGE], RmepId=[GAUGE], CfmMdIndex=[GAUGE], CfmMdIndex=[GAUGE], CfmMaIndex=[GAUGE], Dmac=[OPAQUE], HighestDefect=[INTEGER], MdName=[STRING], MdLevel=[INTEGER], MaName=[STRING])EOAM1AG/4/CCFAULTALARM:OID 1.3.6.1.4.1.2011.5.25.136.1.6.1 A MEP has lost contact. (CfmMdIndex=[GAUGE], CfmMaIndex=[GAUGE], RmepId=[GAUGE], CfmMdIndex=[GAUGE], CfmMdIndex=[GAUGE], CfmMaIndex=[GAUGE], Dmac=[OPAQUE], HighestDefect=[INTEGER], MdName=[STRING], MdLevel=[INTEGER], MaName=[STRING])

Relevant LogsNone



22

4 MSTP Troubleshooting

About This Chapter

4.1 MSTP Topology Change Leads to Service Interruption

HUAWEI NetEngine80E/40E RouterTroubleshooting - Layer 2 Network 4 MSTP Troubleshooting


23

4.1 MSTP Topology Change Leads to Service Interruption

4.1.1 Common CausesAfter MSTP is configured on a device and the MSTP topology changes, services are interrupted.

This fault is commonly caused by one of the following:l MSTP is incorrectly configured.l Physical links flap, causing a large number of TC messages to be sent.l An MSTP-aware device receives MSTP TC messages from clients or transparently-

transmitted MSTP TC messages.

4.1.2 Troubleshooting FlowchartThe troubleshooting of MSTP topology change leads to service interruption is based on thenetwork shown in Figure 4-1.



24

Figure 4-1 Networking diagram of MSTP

S1

GE1/0/1 GE1/0/1GE1/0/2

GE1/0/2GE1/0/1

S2

S3 S4

GE1/0/1GE1/0/2

GE1/0/2

Root Switch: S1

Root Switch: S2

MSTI1:

MSTI2:

Blocked port

Blocked port

Root Switch: S1

CIST(MSTI0):

Blocked port

The troubleshooting roadmap is as follows:l Check that the MSTP status is correct.l Check whether the device has received TC messages.l Check that no physical interface on the device alternates between Up and Down.l Check that the MSTP convergence mode is Normal.




25

Figure 4-2 Troubleshooting flowchart for the fault that an MSTP topology change leads toservice interruption

No

Yes

Yes

Yes

No

Services are interruptedor the device isdisconnected

MSTP status is correct?

Check and modifythe MSTP

configuration

Yes

End

Yes

MSTPrecalculation is

performed?

No

Physical interface on the devicealternates between Up

and Down?

Shut down theflapping interface

Is faultrectified?

MSTPconvergence mode is

Normal?

Collect information

Seek technicalsupport

Set the MSTPconvergence

mode to Normal

Yes

No

No

Yes

No

Seek technicalsupport

Is faultrectified?

Is faultrectified?

No



Procedure

Step 1 Check the status of interfaces on MSTP devices.

Check the role of each MSTP-enabled port in each instance.



26

On the network shown in Figure 4-1, there is only one MSTP ring, which means that eachinstance can have only one blocked interface.Run the display stp brief command on each deviceto check whether the status of each port is normal.

Run the display stp brief command in any view to check the MSTP status on S1.As shown inFigure 4-1, in instances 0 and 1, S1 functions as a root bridge and all ports on S1 are designatedports.In instance 2, one port on S1 is a designated port and the other port is a root port.Both portsare in the Forwarding state.

[S1] display stp brief MSTID Port Role STP State Protection 0 GigabitEthernet1/0/1 DESI FORWARDING NONE 0 GigabitEthernet1/0/2 DESI FORWARDING NONE 1 GigabitEthernet1/0/1 DESI FORWARDING NONE 1 GigabitEthernet1/0/2 DESI FORWARDING NONE 2 GigabitEthernet1/0/1 ROOT FORWARDING NONE 2 GigabitEthernet1/0/2 DESI FORWARDING NONE

Run the display stp brief command in any view to check the MSTP status on S2. As shown inFigure 4-1, in instances 2, S2 functions as a root bridge and all ports on S2 are designated ports.Inother instances, one ports on S2 is a designated port and the other port is a root port. Both ofthem are in the Forwarding state.

[S2] display stp brief MSTID Port Role STP State Protection 0 GigabitEthernet1/0/1 ROOT FORWARDING NONE 0 GigabitEthernet1/0/2 DESI FORWARDING NONE 1 GigabitEthernet1/0/1 ROOT FORWARDING NONE 1 GigabitEthernet1/0/2 DESI FORWARDING NONE 2 GigabitEthernet1/0/1 DESI FORWARDING NONE 2 GigabitEthernet1/0/2 DESI FORWARDING NONE

Run the display stp brief command in any view to check the MSTP status on S3. As shown inFigure 4-1, in instance 2, one port on S3 is an Alternate port and the other port is a root port.The Alternate port is blocked and in the Discarding state.In other instances, one port on S3 is adesignated port and the other port is a root port. Both of them are in the Forwarding state.

[S3] display stp brief MSTID Port Role STP State Protection 0 GigabitEthernet1/0/1 DEST FORWARDING NONE 0 GigabitEthernet1/0/2 ROOT FORWARDING NONE 1 GigabitEthernet1/0/1 DEST FORWARDING NONE 1 GigabitEthernet1/0/2 ROOT FORWARDING NONE 2 GigabitEthernet1/0/1 ALTE DISCARDING NONE 2 GigabitEthernet1/0/2 ROOT FORWARDING NONE

Run the display stp brief command in any view to check the MSTP status on S4. As shown inFigure 4-1, in instance 0, one port on S4 is an Alternate port and the other port is a root port.The Alternate port is blocked and in the Discarding state.In instance 2, one port on S4 is adesignated port and the other port is a root port. Both of them are in the Forwarding state.

[S4] display stp brief MSTID Port Role STP State Protection 0 GigabitEthernet1/0/1 ALTE DISCARDING NONE 0 GigabitEthernet1/0/2 ROOT FORWARDING NONE 1 GigabitEthernet1/0/1 ALTE DISCARDING NONE 1 GigabitEthernet1/0/2 ROOT FORWARDING NONE 2 GigabitEthernet1/0/1 DESI FORWARDING NONE 2 GigabitEthernet1/0/2 ROOT FORWARDING NONE

l On the network shown in Figure 4-1, each instance has only one port in the Discardingstate and the other port is in the Forwarding state.If several ports are in the Discarding state,an MSTP calculation error occurs. To solve this problem, go to Step 6.

l If the MSTP status is correct, go to Step 2.



27

Step 2 Check that the MSTP configuration is correct.Run the display stp region-configuration command to view mappings between VLANs andinstances.[S1] display stp region-configurationOper Configuration: Format selector :0 Region name :huawei Revision level :0

Instance Vlans Mapped 0 21 to 4094 1 1 to 10 2 11 to 20l Check whether mappings between VLANs and instances are correct.If the mapping

between a VLAN and an instance is incorrect, run the instance command to map the VLANto a specified spanning tree instance. Run the active region-configuration command toactive the mapping between the VLAN and instance configured by using the instancecommand.

Run the display current-configuration command to view the MSTP configuration in theconfiguration file of the device.l Check interface configurations to confirm that MSTP-enabled interfaces have been

configured with the command (for example bpdu-tunnel enable) to enable protocolpackets to be sent to the CPU.

l Check whether MSTP is disabled on the interfaces connecting to user terminals or theinterfaces are configured as edge interfaces.

l If an MSTP-enabled device is configured with a BPDU tunnel, check whether the BPDUtunnel configuration is correct. For BPDU tunnel configurations, see the chapter "BPDUTunnel Configuration" in the NE80E/40E Configuration Guide - LAN Access and MANAccess .

l Check whether a port is added to a VLAN correctly.For VLAN configurations, see thechapter "VLAN Configuration" in the NE80E/40E Configuration Guide - LAN Access andMAN Access .

l If the MSTP configuration is correct, go to Step 3.

Step 3 Check that no MSTP recalculation is performed.

Run the display stp command in any view to check whether the device has received TCmessages.[S1] display stp -------[CIST Global Info][Mode MSTP]-------CIST Bridge :57344.00e0-fc00-1597Bridge Times :Hello 2s MaxAge 20s FwDly 15s MaxHop 20CIST Root/ERPC :0 .0018-826f-fc7a / 20000CIST RegRoot/IRPC :57344.00e0-fc00-1597 / 0CIST RootPortId :128.2BPDU-Protection :disabledTC or TCN received :0TC count per hello :0STP Converge Mode :NomalTime since last TC :2 days 14h:16m:15s -------[MSTI 1 Global Info]-------MSTI Bridge ID :4096.00e0-fc00-1597MSTI RegRoot/IRPC :4096.00e0-fc00-1597 / 0MSTI RootPortId :0.0Master Bridge :57344.00e0-fc00-1597Cost to Master :0TC received :0TC count per hello :2



28

l If values of the TC or TCN received, TC count per hello, TC received, and TC count perhello fields in the command output increase, the device has received TC messages and thenetwork topology has changed. In this case, you need to view log messages MSTP/6/SET_PORT_DISCARDING and MSTP/6/SET_PORT_FORWARDING to checkwhether the role of an MSTP-enabled port changes.– If the port role does not change, go to Step 4.– If the port role changes, go to Step 6.

NOTE

If a multi-process has been created on the device and TC notification has been configured in themulti-process, when the topology of the multi-process changes, a TC message is sent to the process0 for instructing devices in process 0 to refresh their MAC and ARP address tables. In this manner,devices on the network can re-select links to forward traffic, ensuring non-stop traffic.

l If the values in the TC or TCN received, TC count per hello, TC received, and TC countper hello fields in the command output are 0s, it indicates that the device does not receiveany TC message. In this case, contact Huawei technical support personnel.

Step 4 Check that no interface on the device alternates between Up and Down.

View the log message IFNET/4/IF_STATE to check whether an MSTP-enabled port alternatesbetween Up and Down.

l If an MSTP-enabled interface alternates between Up and Down, it indicates that theinterface flaps. If a physical interface frequently alternates between Up and Down, theMSTP status of the device on the network will become unsteady. As a result, a large numberof TC messages are generated; ARP entries and MAC entries are frequently deleted;services are interrupted. Run the shutdown command on the flapping interface. If servicesare not restored after the flapping interface is shut down, go to Step 5.

l If no interface flaps, go to Step 5.

Step 5 Check that the MSTP convergence mode is Normal.

Run the display stp command in any view to check the MSTP convergence mode of the device.

[S1] display stp-------[CIST Global Info][Mode MSTP]-------CIST Bridge :57344.00e0-fc00-1597Bridge Times :Hello 2s MaxAge 20s FwDly 15s MaxHop 20CIST Root/ERPC :0 .0018-826f-fc7a / 20000CIST RegRoot/IRPC :57344.00e0-fc00-1597 / 0CIST RootPortId :128.2BPDU-Protection :disabledTC or TCN received :0TC count per hello :0STP Converge Mode :NormalTime since last TC :2 days 14h:16m:15s -------[MSTI 1 Global Info]-------MSTI Bridge ID :4096.00e0-fc00-1597MSTI RegRoot/IRPC :4096.00e0-fc00-1597 / 0MSTI RootPortId :0.0Master Bridge :57344.00e0-fc00-1597Cost to Master :0TC received :0TC count per hello :2

l If the convergence mode is Normal, go to Step 6.l If the convergence mode is Fast, run the stp converge normal command to change the

convergence mode to Normal. If services are not restored after the convergence mode ischanged, go to Step 6.



29


----End


Relevant AlarmsMSTP_1.3.6.1.4.1.2011.5.25.42.4.2.1 hwMstpiPortStateForwarding

MSTP_1.3.6.1.4.1.2011.5.25.42.4.2.2 hwMstpiPortStateDiscarding

MSTP_1.3.6.1.2.1.17.0.2 TOPOC

Relevant LogsMSTP/6/RECEIVE_MSTITC

VOSCPU/4/CPU_USAGE_HIGH



30

5 RRPP Troubleshooting

About This Chapter

5.1 RRPP Loop Occurs Temporarily

HUAWEI NetEngine80E/40E RouterTroubleshooting - Layer 2 Network 5 RRPP Troubleshooting


31

5.1 RRPP Loop Occurs Temporarily

5.1.1 Common CausesAfter RRPP is configured on a device, a loop occurs temporarily.

This fault is commonly caused by one of the following:l The configuration is incorrect.l Values of the Failtime timers configured for nodes along the RRPP ring are different.

5.1.2 Troubleshooting FlowchartTemporary RRPP loop troubleshooting is based on the network shown in Figure 5-1.

Figure 5-1 Networking diagram of RRPP

SwitchA

SwitchB

Ethernet0/0/4

Ethernet0/0/8Ethernet0/0/1

SwitchC

Ethernet0/0/4

Ethernet0/0/8

Ethernet0/0/2

The troubleshooting roadmap is as follows:l Check that every node on the RRPP ring is correctly configured.l Check that the Failtime timer of every node on the RRPP ring is set to the same value.




32

Figure 5-2 Troubleshooting flowchart for the fault that an RRPP loop occurs temporarily

RRPP loop occurs temporarily

Every node on The RRPP ring is correctly configured?

Failtime timer of every node on the

RRPP ring is set to the same value?

Collect information


Correct the configurations

Modify the configurations Is fault rectified?

Is fault rectified?

End

Yes

Yes

No

No

No

No

Yes

Yes



ProcedureStep 1 Check that every node on the RRPP ring is correctly configured.

Run the display this command in the RRPP view of each node on the RRPP ring to view RRPPconfigurations.[RouterA-rrpp-domain-region1] display this#rrpp domain 1 control-vlan 100 protected-vlan reference-instance 0 timer hello-timer 1 fail-timer 3 ring 1 node-mode master primary-port Ethernet1/0/2 secondary-port Ethernet1/0/4 level 0 ring 1 enable#return

Check whether all nodes on the RRPP ring belong to the same domain, whether the nodes areconfigured with the same control VLAN ID and instance number, and whether the RRPP ringhas only one master node.



33

l If all configurations are correct, go to Step 2.l If any of the preceding configurations is incorrect, RRPP configurations may be incorrect.

For correct configurations, see the chapter "RRPP Configuration" in the NE80E/40EConfiguration Guide - LAN Access and MAN Access.

Step 2 Check that the Failtime timer of every node on the RRPP ring is set to the same value.

Run the display rrpp verbose domain domain-id command in any view to check detailed RRPPconfigurations.

[RouterA-rrpp-domain-region1] display rrpp verbose domain 1Domain Index : 1Control VLAN : major 20 sub 21Hello Timer : 1 sec(default is 1 sec) Fail Timer : 3 sec(default is 3 sec) RRPP Ring : 1Ring Level : 0Node Mode : MasterRing State : CompleteIs Enabled : Enable Is Active : YesPrimary port : Port status: UPSecondary port: Port status: BLOCKEDl If the Failtime timers of the nodes on the RRPP ring are set to different values, correct the

configurations according to the chapter "RRPP Configuration" in the NE80E/40EConfiguration Guide - LAN Access and MAN Access.

l If the Failtime timer of every node on the RRPP ring is set to the same value, go to Step3.


----End


Relevant AlarmsRRPP_1.3.6.1.4.1.2011.5.25.113.4.2 hwRrppRingFail

Relevant LogsRRPP/3/FAIL

RRPP/5/PBLK

RRPP/5/RESTORE



34

6 PPP Troubleshooting

About This Chapter

NOTE

PPP cannot be configured on the X1 and X2 models of the NE80E/40E.

6.1 Protocol Status of a PPP Interface Is Down


6.3 ATM TroubleshootingThis chapter describes common causes of Asynchronous Transfer Mode (ATM) faults, andprovides the corresponding troubleshooting flowcharts, troubleshooting procedures, alarms,logs, and commands.

6.4 The Ping Fails on Both Ends of an ATM NetworkThis section describes the troubleshooting flowchart and provides a step-by-step troubleshootingprocedure for the fault that the ping fails on both ends of an ATM network.

6.5 Troubleshooting Cases

HUAWEI NetEngine80E/40E RouterTroubleshooting - Layer 2 Network 6 PPP Troubleshooting


35

6.1 Protocol Status of a PPP Interface Is Down

6.1.1 Common CausesAfter an interface is configured with PPP, LCP negotiation fails, which causes the protocol statusof the interface to be Down.

This fault is commonly caused by one of the following:

l PPP configurations on the two ends of the link are incorrect.l The physical status of the interface is Down.l PPP packets are discarded.l A loop occurs on the link.l The link delay is too long.

6.1.2 Troubleshooting FlowchartThe troubleshooting roadmap is as follows:

l Check that PPP configurations on the two ends of the link are correct.l Check that the physical status of the interface is Up.l Check that the interface can sent and receive protocol packets.l Check that the link is loop-free.l Check that the link delay is tolerant.




36

Figure 6-1 Troubleshooting flowchart for an LCP negotiation failure

PPP configurations on the two ends of the link

are correct?

Physical status of the interface is Up?

Interface can sent and receive protocol

packets?

Link is loop-free?

Modify PPP configurations

Locate and rectify transmission or

lower-layer faults

Eliminate the loop

Locate and rectify transmission or

lower-layer faults

LCP negotiation fails

Yes

No


No

End

Is fault rectified?

Is fault rectified?

Is fault rectified?

Is fault rectified?

Yes

Yes

Yes

Yes

Yes

No

No

No

No

Link delay is tolerant Check the link delay Is fault rectified?

Yes

No

Yes

No

Yes

No

Yes

No



Procedure

Step 1 Check that PPP configurations on the two ends of the link are correct.

Run the display this command in the view of the interface whose protocol status is Down tocheck PPP configurations.

[HUAWEI-Pos1/0/1] display this#interface Pos1/0/1 link-protocol ppp undo shutdown ip address 10.10.1.1 255.255.255.0#return



37

l Check whether the following configurations on the two ends match each other. If not,modify the configuration referring to the chapter "PPP and MP Configuration" in theNE80E/40E Configuration Guide - WAN Access.– Check whether the authenticator and authenticatee are configured with the same

authentication mode. The ppp authentication-modeauthentication-mode commandindicates the authentication mode adopted by the local end that functions as theauthenticator. You need to check the authentication mode adopted by the peer. Forexample, if the ppp pap local-user user-name password simple password commandhas been configured, it means that the peer adopts PAP authentication.

– Check whether both ends are bundled into an MP-group or neither of the two ends isbundled into an MP-group. If one end has been bundled into an MP-group, the otherend must be bundled into the same MP-group. If the ppp mp mp-group interface-number command is configured, it means that the interface has been bundled into anMP-group.

– Check whether the authenticator and authenticatee are configured with the samepassword for PPP authentication.– If PAP authentication is adopted, do as follows to check the configured user name

and password:Check the user name and password of the authenticatee in the interface view.[HUAWEI-Pos1/0/0] display this#interface Pos1/0/0 link-protocol pppppp pap local-user huawei password simple huawei undo shutdown#returnCheck the user name and password of the authenticator in the AAA view.[HUAWEI] aaa[HUAWEI-aaa] display this#aaa local-user huawei password simple huawei#return

– If the authenticator adopts CHAP authentication and is configured with a user name,do as follows to check the user name and password:Check the user name of the authenticatee in the interface view, and then check thepassword in the AAA view based on the user name.[HUAWEI-Pos1/0/0] display this#interface Pos1/0/0 link-protocol pppppp chap user huawei undo shutdown#return[HUAWEI-Pos1/0/0] aaa[HUAWEI-aaa] display this#aaa local-user huawei password simple huawei#returnCheck the user name and password of the authenticator in the AAA view.[HUAWEI] aaa[HUAWEI-aaa] display this



38

#aaa local-user huawei password simple huawei#return

– If the authenticator adopts CHAP authentication but is not configured with a username, do as follows to check the user name and password:Check the user name and password of the authenticatee in the interface view.[HUAWEI-Pos1/0/0] display this#interface Pos1/0/0 link-protocol ppp ppp chap user huawei ppp chap password simple huawei undo shutdown#returnCheck the user name and password of the authenticator in the AAA view.[HUAWEI] aaa[HUAWEI-aaa] display this#aaa local-user huawei password simple huawei#return

l If the preceding configurations are correct but the fault persists, go to Step 2.

Step 2 Check that the physical status of the interface is Up.

Run the display interface interface-type interface-number command to check the physical statusof the interface.

l If the physical status of the interface is Down, you need to rectify the physical fault of theinterface. For detailed troubleshooting procedures, see "Physical InterconnectionTroubleshooting".

l If the physical status of the interface is Up but the fault persists, go to Step 3.

Step 3 Check that the interface can sent and receive protocol packets.

Run the display interface interface-type interface-number command to check the number ofsent packets and received packets to determine whether the interface sends and receives protocolpackets.

[HUAWEI] display interface Pos 1/0/0Pos1/0/0 current state : UPLine protocol current state : UPLast line protocol up time : 2010-02-05 06:35:43Description:HUAWEI, Pos1/0/0 InterfaceRoute Port,The Maximum Transmit Unit is 4470, Hold timer is 10(sec)Internet Address is 108.108.1.1/24Link layer protocol is PPPLCP opened, IPCP openedThe Vendor PN is HFBR-57E0PThe Vendor Name is AVAGOPort BW: 155M, Transceiver max BW: 155M, Transceiver Mode: MultiModeWaveLength: 1310nm, Transmission Distance: 2000mPhysical layer is Packet Over SDHScramble enabled, clock master, CRC-32, loopback: noneFlag J0 "NetEngine "Flag J1 "NetEngine "Flag C2 22(0x16) SDH alarm: section layer: none line layer: none



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path layer: none SDH error: section layer: B1 0 line layer: B2 0 REI 44 path layer: B3 0 REI 23Statistics last cleared:never Last 300 seconds input rate 24 bits/sec, 0 packets/sec Last 300 seconds output rate 24 bits/sec, 0 packets/sec Input: 70945 packets, 1135144 bytes Input error: 0 shortpacket, 0 longpacket, 0 CRC, 0 lostpacket Output: 70945 packets, 1135140 bytes Output error: 0 lostpackets Output error: 0 overrunpackets, 0 underrunpackets l If the number of received or sent packets is 0, or the number does not increase, it indicates

that packets are discarded during transmission. Check whether the physical connection iscorrect. For detailed information, see "Physical Interface Cannot Go Up".

l If the physical connection is correct, you need to locate the cause of packet loss. For detailedtroubleshooting procedures, see "Packet Loss Troubleshooting".

l If packets can be received and sent but the fault persists, go to Step 4.

CAUTIONDebugging affects the system performance. Therefore, after debugging, run the undo debuggingall command to disable it immediately.

In addition, you can run the debugging ppp all interface interface-type interface-numbercommand to check the number of sent and received protocol packets and the status changes ofthe PPP state machine.

Jun 2 2010 17:19:41.310.1 HUAWEI PPP/7/debug2:Slot=1; PPP Event: Pos1/0/0 LCP TO+(Timeout with counter > 0) Event state acksent , Retransmit = 4Jun 2 2010 17:19:41.310.2 HUAWEI PPP/7/debug2:Slot=1; PPP Packet: Pos1/0/0 Output LCP(c021) Pkt, Len 18 State acksent, code ConfReq(01), id 3, len 14 MRU(1), len 4, val 1176 MagicNumber(5), len 6, val 00abb891Jun 2 2010 17:19:41.310.1 HUAWEI PPP/7/debug2:Slot=1; PPP Packet: Pos1/0/0 Input LCP(c021) Pkt, Len 18 State acksent, code ConfAck(02), id 3, len 14 MRU(1), len 4, val 1176 MagicNumber(5), len 6, val 00abb891Jun 2 2010 17:19:41.310.2 HUAWEI PPP/7/debug2:Slot=1; PPP Event: Pos1/0/0 LCP RCA(Receive Config Ack) Event state acksent

Step 4 Check that the link is loop-free.

Run the display interface interface-type interface-number command to check the physical statusof the interface.

[HUAWEI] display interface Pos 1/0/2Pos1/0/2 current state : UPLine protocol current state : DOWNDescription:HUAWEI, Pos1/0/2 InterfaceRoute Port,The Maximum Transmit Unit is 4470, Hold timer is 10(sec)Internet protocol processing : disabled



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Link layer protocol is PPP, loopback is detectedLCP closedThe Vendor PN is HFBR-57E0PThe Vendor Name is AVAGOPort BW: 155M, Transceiver max BW: 155M, Transceiver Mode: MultiModeWaveLength: 1310nm, Transmission Distance: 2000mPhysical layer is Packet Over SDHScramble enabled, clock master, CRC-32, loopback: localFlag J0 "NetEngine "Flag J1 "NetEngine "Flag C2 22(0x16) SDH alarm: section layer: none line layer: none path layer: none SDH error: section layer: B1 22 line layer: B2 94 REI 145 path layer: B3 44 REI 86Statistics last cleared:never Last 300 seconds input rate 56 bits/sec, 0 packets/sec Last 300 seconds output rate 56 bits/sec, 0 packets/sec Input: 40530 packets, 890400 bytes Input error: 0 shortpacket, 0 longpacket, 2 CRC, 0 lostpacket Output: 36512 packets, 946612 bytes Output error: 0 lostpackets Output error: 0 overrunpackets, 0 underrunpackets

l If loopback is detected is displayed, it indicates that a loop occurs on the link. You needto locate the cause of the loop and eliminate the loop.

l If no loop occurs but the fault persists, go to Step 5.

Step 5 Check that the link delay is tolerant.Use a tester to test the link delay. On a Huawei router, the transmission of a PPP packet timesout in 3 seconds, and the timeout period is configurable. The link delay must be smaller than thetimeout period.l If the link delay is too long, replace or maintain the relevant device.l If the link delay is tolerant but the fault persists, go to Step 6.

Step 6 Collect the following information and contact Huawei technical support personnel.l Results of the preceding troubleshooting procedurel Configuration files, log files, and alarm files of the devices

----End


Relevant AlarmsNone.

Relevant LogsNone.




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6.2.1 Half of Packets Are Discarded the First Minute After an MP-Group Link Fails

Fault SymptomRouter A and Router B are connected by using an MP-group interface consisting of two CE1interfaces. All timeslots of each CE1 interface are bundled into a synchronous serial interfaceto transmit services.

Figure 6-2 Networking for half of packets discarded the first minute after an MP-Group linkfails

RouterA RouterB

MP-GroupCE1 1/0/0

CE1 1/0/1

CE1 1/0/0

CE1 1/0/1

After the link of CE1 1/0/0 fails, 50% packets are dropped in the first minute, and the linkrecovers and no packet is dropped in two minutes.

Fault AnalysisAfter an MP-group member link becomes unavailable, the traffic transmitted over this linkautomatically switches to the other available link.

In addition, a PPP-enabled router sets the PPP status of the link to Down after failing to receive10 consecutive Hold time messages.

A Hold time message is sent every 10 seconds by default, and it takes 100s to send 10 Hold timepackets. This is why the peer router can detect that the link is Down about two minutes (100s)after the PPP status is set down.

Router B continues to send messages along the failed link 100s after the failure occurs. As aresult, half of packets are dropped during this period of time. After Router A sets the PPP statusto Down, Router B detects that the link goes Down and no longer sends messages along thefailed link, and thus no message is dropped.

You can set a shorter interval at which a Hold time message is sent to rectify the fault.

Run the following commands on two routers on the two ends of the PPP link:

Procedure


Step 2 Run the interface serial 1/0/0:0 command to enter the view of the synchronous serial interfacecomposed of CE1 interfaces.

Step 3 Run the timer hold 1 command to set the interval at which a Hold time message is sent to 1second.

Step 4 Run the shutdown and undo shutdown commands to restart the CE1 interface.



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After the configurations, run the ping command on Router A or Router B to ping the peer. Nopacket is dropped. The fault is then rectified.

----End

SummarySet a smaller interval at which a Hold time message is sent on both ends of a PPP link, enablinga rapid response to the link status change on an unstable network.

6.2.2 Incorrect Configurations of Member Interfaces Cause the MP-group Link to Work Unstably

Fault SymptomRouterA functions as the egress of the network and accesses the Internet through RouterB.RouterA and RouterB intercommunicate through an MP-group link on which there is atransmission device. An MP-group link is formed by bundling eight CE1 links.

Figure 6-3 Networking diagram of MP-Group

RouterA RouterB

MP-Group

InternetUsersMP-Group

TransmissionDevice

When a user attached to RouterA accesses the Internet, the DNS server sometimes cannot bepinged successfully; the long delay of packets and packet loss may frequently occur; the webpagesometimes cannot be accessed.

Fault Analysis1. On the transmission device, check the status of the physical interface and optical fiber. The

physical interface and optical fiber are detected normal.2. On RouterA and RouterB, run the display interface command to view information about

the MP-group interface and its member interfaces.Check the following information:l Whether the interface becomes Upl Whether the clock mode is correctl Whether the line coding/decoding formats on both ends are consistentl Whether loopback is configuredl Whether alarms are generated[RouterA] display controller e1 1/0/0E1 1/0/0 current state : UPDescription : E1 1/0/0 InterfacePhysical layer is Packet Over NO-CRC4clock slave, linecode hdb3 , loopback nonesection layer: alarm: LOS



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line layer: alarm: nonepath layer: alarm: none [RouterB] display controller e1 1/0/0E1 1/0/0 current state : UPDescription : E1 1/0/0 InterfacePhysical layer is Packet Over NO-CRC4clock master, linecode hdb3 , loopback nonesection layer: alarm: LOSline layer: alarm: nonepath layer: alarm: none When a transmission device is on the link, the router needs to obtain clock signals from thetransmission device, which requires the router to work in slave clock mode.The CE1 interface on RouterA is configured to work in slave clock mode, whereas the CE1interface on RouterB is configured to work in master clock mode. Therefore, the link isunstable due to incorrect clock configuration.

Procedure

Step 1 Run the system-view command on RouterB to enter the system view.

Step 2 Run the controller e1 1/0/0 command to enter the CE 1 interface view.

Step 3 Run the clock slave command to change the clock mode of the CE1 interface to the slave clockmode.

Step 4 Configure the same on each member interface of the MP-group interface.Check the status of the CE1 interfaces on the routers on both ends. You can find that the link isstable and packets can be transmitted and received normally. The fault is rectified.

----End

SummaryFunctioning as the synchronous interface, the CE1 interface can work in data terminal equipment(DTE) mode and data circuit-terminating equipment (DCE) mode. In addition, the interfacerequires a clock mode.

On the CE1 interface, you can select one of the following clock modes:l Master clock mode: uses the internal clock signal.l Slave clock mode: uses the line clock signal.

When the CE1 interfaces of two devices are directly connected, one interface should beconfigured to work in master clock mode and the other interface should be configured to workin slave clock mode.

When the CE1 interface of a device is connected to a transmission device, the CE1 interfacemust be configured to work in salve clock mode and obtains clock signals from the transmissiondevice.



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6.3 ATM TroubleshootingThis chapter describes common causes of Asynchronous Transfer Mode (ATM) faults, andprovides the corresponding troubleshooting flowcharts, troubleshooting procedures, alarms,logs, and commands.

6.4 The Ping Fails on Both Ends of an ATM NetworkThis section describes the troubleshooting flowchart and provides a step-by-step troubleshootingprocedure for the fault that the ping fails on both ends of an ATM network.

6.4.1 Common CausesThis fault is commonly caused by one of the following:l The physical link goes Down.l The protocol goes Down.

6.4.2 Troubleshooting FlowchartFigure 6-4 shows the troubleshooting flowchart.



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Figure 6-4 Troubleshooting flowchart for a ping failure on both ends of an ATM network

End

Yes

Yes

Yes

Yes

No

No

No

No

Connect the optical fiber correctly

No

No

No

NoSet the same bandwidth

and service type

Set the same VPI/VCI values

Set the same protocol type and encapsulation

type

Two ends of the ATM network cannot

access each other

Ask for technical support

Yes

Yes

Yes

Yes

Is the fault rectified?




Check that the optical fiber is

correctly connected

Check that the VPI/VCI values on both ends are the

same?

Check that the protocol types and

encapsulation types are the same

Check that the bandwidths and service

types are the same



Procedure

Step 1 Check that the optical fiber is properly installed.l If the optical fiber is not properly installed, see "Physical Interconnection Troubleshooting."l If the optical fiber is properly installed, see Step 2.

Step 2 Check that PVCs on the interfaces on both ends are the same.

The PVCs on the interfaces on both ends must be the same because the ATM interfaces use thePVCs for communication. If the PVCs are configured with IPoA, check whether the protocoladdress mapping is correctly configured. If two devices are directly connected, the PVC mapped



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from the local to the peer IP address on the local end must be the same as the PVC mapped fromthe peer to the local IP address on the peer end.

l If the PVCs on both ends are different, change them to be the same. If the fault persists, goto Step 3.

l If the PVC values on both ends are the same, go to Step 3.

Step 3 Check that the configurations and protocol types on the ATM interfaces on the two ends are thesame.

Check that the protocols configured for the PVCs on the ATM interfaces on the two ends arethe same. If the routing protocol over ATM is Open Shortest Path First (OSPF), the mappingentry configured on the ATM interfaces must contain broadcast. If the ATM interfaces on thetwo ends can use small packets, but not big packets, to ping each other, check that the MTUs onthe ATM interfaces are the same. If the MTUs on the ATM interfaces are different, go to Step4.

Step 4 Collect the following information and contact Huawei technical support personnel:l Results of the preceding troubleshooting procedurel Configuration, log, and alarm files

----End

6.4.4 Relevant Alarms and LogsNone.

6.5 Troubleshooting Cases6.5.1 OSPF Neighbor Relationship Cannot Be Set Up Between P2PATM Sub-interfaces

Fault SymptomAs shown in Figure 6-5, two P2P ATM sub-interfaces are directly connected. The P2P ATMsub-interfaces can ping each other successfully, but the OSPF neighbor relationship cannot beset up between them.



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Figure 6-5 Networking diagram for a fault that the OSPF neighbor relationship cannot be setup between two P2P ATM sub-interfaces

ATM3/0/0.1 ATM3/0/0.1

RouterA RouterB

Area 0

Fault Analysis

On a P2P network, OSPF packets are broadcast.

The PVC configurations on both ATM interfaces show that broadcast is configured not for IPoAbut for OSPF. As a result, the OSPF neighbor relationship cannot be set up between the twoATM interfaces.

Procedure


Step 2 Run the interface atm interface-number.sub-number command to enter the ATM sub-interfaceview.

Step 3 Run the pvc vpi/vci command to enter the PVC view.

Step 4 Run the map ip ip-address broadcast command to allow packets to be broadcast over the PVC.

After the preceding configuration is complete, the OSPF neighbor relationship is set upsuccessfully.

----End

Summary

Note the following points when configuring ATM:

l The encapsulation types and protocol types must be the same on both ends of the ATMPVC.

l The PVC types are determined by the upper layer protocols.



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troubleshooting - layer 2 network(v600r003c00_02)

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