12.OSPF Troubleshooting

7/28/2019 12.OSPF Troubleshooting

1/13

Cisco CCNP ROUTE TrainingInstructor: Joe Rinehart, CCIE #14256

OSPFTroubleshooting

Cisco CCNP ROUTE Training

OSPF Troubleshooting

In This Lesson:

Troubleshooting Model

Common Issues and Resolution Steps

Relevant Debug and Show Commands

Dealing with Cisco TAC




1. Define the Problem

2. Gather the Facts

3. Document the Facts

4. Consider the Possibilities

5. Create an Action Plan

6. Implement the Action Plan

7. Repeat Until Resolution

8. Document the Solution


2/13




Problem Resolution Methodology




1. Neighbor Relationship Problems

2. Routes Missing from Table

3. Address Summarization Problems




Neighbor Relationship Problems

Neighbor Not Establishing Relationship

Possible Cause: Desired interfacesconfigured as passive

Alternatively execute the show ipprotocols and look for Passive-Interface(s) entry

Delete the passive-interfacecommand

Possible Cause: Misconfiguredneighbor authentication

Execute the show ip ospfinterface command to ifauthentication is in use

Frame Relay

WAN

607

706

VLAN 79

VLAN 910

R6

R7 R8

R10R9

608

806

708807

OSPF

Area 0

OSPF

Area 79OSPF

Area 8

(Stub)

OSPF

Area 910

Backbone?


3/13






Possible Cause: Misconfiguredneighbor authentication

Execute the show running-config command to verify that

both the ip ospf [key |message-digest-key] and ipospf authentication [message-digest] command are correct andin place and that keys match

Add either or both statements

with correct syntax if missing

Frame Relay

WAN

607

706

VLAN 79

VLAN 910

R6

R7 R8

R10R9

608

806

708807

OSPF

Area 0

OSPF

Area 79OSPF

Area 8

(Stub)

OSPF

Area 910

Backbone?






Possible Cause: Misconfigured MTUvalues on neighbor interfaces

Execute the show interfacecommand and note the MTUoutput on all/both neighbors

Enter interface configuration modeand equalize the MTU settingusing the ip mtu command and/or set to defaults

Frame Relay

WAN

607

706

VLAN 79

VLAN 910

R6

R7 R8

R10R9

608

806

708807

OSPF

Area 0

OSPF

Area 79

OSPFArea 8

(Stub)

OSPF

Area 910

Backbone

?Cisco CCNP ROUTE Training





Possible Cause: Primary subnets notmatching

Execute the show ip interface command to verifythe primary IP address configuredon the interfaces of affecteddevices

Change IP addressing if primarysubnets are not on the samenetwork/subnet

Frame Relay

WAN

607

706

VLAN 79

VLAN 910

R6

R7 R8

R10R9

608

806

708807

OSPF

Area 0

OSPF

Area 79OSPF

Area 8

(Stub)

OSPF

Area 910

Backbone?


4/13






Possible Cause: Multicast traffic beingblocked between devices

Execute the show ip interfaceand show access-list command

to discover if any filtering is beingdone on the affected interfaces

Add statements permitting224.0.0.5/6 is necessary

Execute show interface to

determine if interface is up/up

Replace cable or replaceinterface/device to resolve

Frame Relay

WAN

607

706

VLAN 79

VLAN 910

R6

R7 R8

R10R9

608

806

708807

OSPF

Area 0

OSPF

Area 79OSPF

Area 8

(Stub)

OSPF

Area 910

Backbone?






Possible Cause: Network statementmisconfigured under OSPF

Execute the show ip OSPFinterface to discover if OSPF hascorrectly identified the interfaces

Execute the show running-config to verify that the networkstatements are correctlyconfigured in OSPF

Delete and recreate the networkstatements with the correctsubnet and mask combinations

Frame Relay

WAN

607

706

VLAN 79

VLAN 910

R6

R7 R8

R10R9

608

806

708807

OSPF

Area 0

OSPF

Area 79

OSPFArea 8

(Stub)

OSPF

Area 910

Backbone





Possible Cause: Non-Broadcast Network

Execute the show ip ospf interfaceto discover and note if the network

type under the Network Type entryis identified as NON_BROADCAST

Execute the show running-configcommand and verify if the neighbor command is present

If the statement is missing, add thestatic neighbor command on the DR/BDR routers

Frame Relay

WAN

607

706

VLAN 79

VLAN 910

R6

R7 R8

R10R9

608

806

708807

OSPF

Area 0

OSPF

Area 79OSPF

Area 8

(Stub)

OSPF

Area 910

Backbone?


5/13





Possible Cause: Priority 0 configured

Execute the show ip ospf neighborto verify the configured priority of theneighbor (1 is default)

If all neighbors are showing priority of

0, manually change the priority of thedesired DR/BDR

Possible Cause: Mismatched timers

Execute the show ip ospf interfaceand note the values of the Timer

Intervals entry (Hello XX, Dead XX)

Change values if they do not match

Frame Relay

WAN

607

706

VLAN 79

VLAN 910

R6

R7 R8

R10R9

608

806

708807

OSPF

Area 0

OSPF

Area 79OSPF

Area 8

(Stub)

OSPF

Area 910

Backbone?




Routes Missing from Table

Possible Cause: Network statementmisconfigured under OSPF

Execute the show ip OSPF

interface to discover if OSPF hascorrectly identified the interfaces

Execute the show running-configto verify that the networkstatements are correctly configured inOSPF

Delete and recreate the network

statements with the correct subnetand mask combinations

Frame Relay

WAN

607

706

VLAN 79

VLAN 910

R6

R7 R8

R10R9

608

806

708807

OSPF

Area 0

OSPF

Area 79

OSPFArea 8

(Stub)

OSPF

Area 910

Backbone




Routes Missing from Table

Possible Cause: Default routemisconfigured

Execute the show ip route to

discover if a static route to 0.0.0.0exists

Execute the show running-configto verify that the redistribute staticand default-information originate

statements are correctly configured inOSPF

Add the statements if they aremissing from the configuration

Frame Relay

WAN

607

706

VLAN 79

VLAN 910

R6

R7 R8

R10R9

608

806

708807

OSPF

Area 0

OSPF

Area 79OSPF

Area 8

(Stub)

OSPF

Area 910

Backbone?


6/13




Address Summarization Problems

Possible Cause: No subnets in the routingtable in the range of the summary

address

Execute the show ip routecommand to see if any networks

within the range currently exist

Execute the show running-configto verify that the ip area-rangeand/or summary-addressstatement is correctly configured

Delete and recreate the summary

statement with corrections and/or findthe cause of the missing route

Frame Relay

WAN

607

706

VLAN 79

VLAN 910

R6

R7 R8

R10R9

608

806

708807

OSPF

Area 0

OSPF

Area 79OSPF

Area 8

(Stub)

OSPF

Area 910

Backbone?




Address Summarization Problems

Possible Cause: Routers reside in aStub/NSSA area

Execute the show ip route

command to see if any networkswithin the range currently exist

Execute the ip ospfstatement andlook for the statement It is a stubarea

This is normal behavior for stub areas(i.e., to suppress summary routes)

Either change the area type or verifyreachability of the area range orsummary address

Frame Relay

WAN

607

706

VLAN 79

VLAN 910

R6

R7 R8

R10R9

608

806

708807

OSPF

Area 0

OSPF

Area 79

OSPFArea 8

(Stub)

OSPF

Area 910

Backbone




1. OSPF Show Commands

2. OSPF Debug Commands


7/13




OSPF Show Commands

show ip protocols

Data displayed by the command

OSPF status and process-id

Area types configured

Protocols being redistributed

Networks being advertised

Neighbors/gateways

Helpful in troubleshooting:

Neighbor relationships

Missing routes

Summarization issues

Filtering problems

Frame Relay

WAN

607

706

VLAN 79

VLAN 910

R6

R7 R8

R10R9

608

806

708807

OSPF

Area 0

OSPF

Area 79OSPF

Area 8

(Stub)

OSPF

Area 910

Backbone?




OSPF Show Commands

show ip route ospf


OSPF routes from neighbors

Administrative distance

Cumulative cost metric

Route source/interface


Missing routes

Summarization issues

Filtering problems

General troubleshooting

Frame Relay

WAN

607

706

VLAN 79

VLAN 910

R6

R7 R8

R10R9

608

806

708807

OSPF

Area 0

OSPF

Area 79

OSPFArea 8

(Stub)

OSPF

Area 910

Backbone




OSPF Show Commands

show ip ospf interfaces


Interfaces participating in OSPF

Network type(s)

Neighbor count

Authentication type

Timer values



Local configuration issues

Routing problems

Frame Relay

WAN

607

706

VLAN 79

VLAN 910

R6

R7 R8

R10R9

608

806

708807

OSPF

Area 0

OSPF

Area 79OSPF

Area 8

(Stub)

OSPF

Area 910

Backbone?


8/13




OSPF Show Commands

show ip eigrp neighbors


Active fully adjacent neighbors

Router ID of neighbors

IP address/interface of neighbors

Dead time of neighbors

Neighbor state/DR state



Local configuration issues

Frame Relay

WAN

607

706

VLAN 79

VLAN 910

R6

R7 R8

R10R9

608

806

708807

OSPF

Area 0

OSPF

Area 79OSPF

Area 8

(Stub)

OSPF

Area 910

Backbone?




OSPF Show Commands

show ip ospf database


LSA types per area

Advertising router

Link ID (subnet)

Age


Missing routes

Filtering problems


Frame Relay

WAN

607

706

VLAN 79

VLAN 910

R6

R7 R8

R10R9

608

806

708807

OSPF

Area 0

OSPF

Area 79

OSPFArea 8

(Stub)

OSPF

Area 910

Backbone




OSPF Show Commands

show ip ospf border-routers


Router ID

Advertising router

Area

Whether an ABR or ASBR

Cost to reach


Missing routes

Filtering problems


Frame Relay

WAN

607

706

VLAN 79

VLAN 910

R6

R7 R8

R10R9

608

806

708807

OSPF

Area 0

OSPF

Area 79OSPF

Area 8

(Stub)

OSPF

Area 910

Backbone?


9/13




OSPF Show Commands

show ip ospf


OSPF process ID

Configured areas

Number/types of areas/ranges

Configured area authentication

Times SPF algorithm executed

Interfaces per area on router


Missing routes

Filtering problems


Frame Relay

WAN

607

706

VLAN 79

VLAN 910

R6

R7 R8

R10R9

608

806

708807

OSPF

Area 0

OSPF

Area 79OSPF

Area 8

(Stub)

OSPF

Area 910

Backbone?




OSPF Debug Commands

debug ip ospf adjacency

Debugging neighbor adjacencies



Routing update issues

Stub router problems

debug ip ospf events

Debugging network events


Routing update issues

Convergence issues

Interface flapping

Frame Relay

WAN

607

706

VLAN 79

VLAN 910

R6

R7 R8

R10R9

608

806

708807

OSPF

Area 0

OSPF

Area 79

OSPFArea 8

(Stub)

OSPF

Area 910

Backbone




EIGRP Debug Commands

debug ip spf hello

Debugging neighbor adjacencies



Configuration issues

DR/BDR election problems

Frame Relay

WAN

607

706

VLAN 79

VLAN 910

R6

R7 R8

R10R9

608

806

708807

OSPF

Area 0

OSPF

Area 79OSPF

Area 8

(Stub)

OSPF

Area 910

Backbone?


10/13




1. Understanding TAC

2. Severity Levels

3. Opening a TAC Case

4. Information to Have Ready

5. Working the Case Actively

6. TAC Case Etiquette




Understanding TAC

24x7x365 coverage for all Cisco productlines

Located worldwide (primary sites):

San Jose, CA

Sydney, Australia

Raleigh, NC

Brussels, Belgium

Attachment to open cases

Entitlement tied to valid SMARTNet

service contract




Severity Levels

Severity 1 (S1): Your network orenvironment is down or there is acritical impact to your business

operations. You and Cisco will commit allnecessary resources around the clock toresolve the situation (use care whendesignating a situation as an S1, useescalation if resolution for S2/S3 is notproceeding as you need it to)


11/13




Severity Levels

Severity 2 (S2): Operation of anexisting network or environment is

severely degraded, or significant aspectsof your business operation are negativelyaffected by inadequate performance ofCisco products. You and Cisco will commitfulltime resources during normal businesshours to resolve the situation




Severity Levels

Severity 3 (S3): Operationalperformance of your network orenvironment is impaired while most

business operations remain functional.You and Cisco are willing to commitresources during normal business hoursto restore service to satisfactory levels

Severity 4 (S4):You requireinformation or assistance with Ciscoproduct capabilities, installation, or

configuration. There is little or no effecton your business operations




Opening a TAC Case

By E-mail: [email protected]

On the web:http://www.cisco.com/techsupport/servic

erequest

By Phone:

Asia Pacific +61 2 8446 7411

Australia 1 800 805 227

New Zealand 0800 44 6237

Europe +32 2 704 5555

US/Canada 1 800 553 2447
mailto:[email protected]://www.cisco.com/techsupport/servicerequesthttp://www.cisco.com/techsupport/servicerequesthttp://www.cisco.com/techsupport/servicerequesthttp://www.cisco.com/techsupport/servicerequestmailto:[email protected]


12/13




Information to Have Ready

Must-Have Information

Cisco Service Contract #

Product/Chassis Serial #

Product Model #/HW config

Physical location of the product

Severity Level of the Issue

Very Helpful Information

Accurate description of the issue (andsuccinct case title)

History of the problem

Network topology and explanation




Information to Have Ready

Very Helpful Information

Output from show tech command (ifapplicable) and all other relevant

output

Software versions and types ofequipment

Relevant syslog/TACACS+ logs beforethe issue occurred

Working the Case Actively

Send updates & information as requested Maintain regular communication

Close the case when the issue is resolved




TAC Case Etiquette

Treat the support engineer with courtesyand respect

Realize that TAC is not a substitute for

on-site staff

Create separate TAC cases for each issueunless clearly linked

Realize that you have control over theseverity level

Escalate to the TAC duty manager is youneed to move the case along

Pass along compliments to the supportengineers supervisor


13/13



Key Terms You Should Know

Cisco TAC Cisco Technical Assistance Center, the 24x7x365help desk support system for customers using Cisco products

S1 Severity TAC case severity in which the production

network is down and in a critical state needing immediateresolution

S2 Severity TAC case severity in which the production

network is severely degraded with regards to performance

S3 Severity TAC case severity in which the productionnetwork is impaired but relatively functional

S4 Severity TAC case severity in which the productionnetwork is fully operational but assistance with information,configuration/installation guidance is required



What We Covered





12.OSPF Troubleshooting

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