Cisco Confidential 1 © 2010 Cisco and/or its affiliates. All rights reserved. Configure and Troubleshoot IP Routing Protocols - EIGRP & OSPF Manas R Moothedath Sumit Kothiyal Process Technology Cisco Support Community
Feb 06, 2016
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Configure and Troubleshoot IP Routing Protocols - EIGRP & OSPF
Manas R MoothedathSumit Kothiyal
Process
Technology
CiscoSupport Community
IP Routing Protocols – Part 2
Manas Moothedath and Sumit Kothiyal
Cisco Systems (India) Pvt Limited
26th Mar 2014
EIGRP
EIGRP
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EIGRP packets – a quick recap
Basic troubleshooting of EIGRP issues.
A closer look at typical EIGRP error messages
Practical view of EIGRP failure scenarios
Best practices in EIGRP
AGENDA
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EIGRP Packets – A Quick Recap
- The Hello
R1 R2
Hello
Hello
Network command ENABLES EIGRP.
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EIGRP Packets – A Quick Recap
- The Update
R1 R2
Update
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EIGRP Packets – A Quick Recap
- The Query
- The ReplyR1 R2
R3
X
Query
Reply
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Troubleshooting EIGRP – Effect to cause…
Typical EIGRP error messages – neighborship flapping continuously: a) EIGRP Hold time expired
b) Retry Limit Exceeded
c) Peer restarted
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The EIGRP – STUCK IN ACTIVE
Revisiting the EIGRP Query
“show ip eigrp topology active”
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Understanding the ‘EIGRP Topology’
router B# show ip eigrp topology 170.16.0.0 255.255.0.0
IP-EIGRP topology entry for 172.16.0.0/16State is Passive, Query origin flag is 1, 1 Successor(s), FD is 3757056Routing Descriptor Blocks:12.1.2.2 (Serial1), from 12.1.2.2, Send flag is 0x0Composite metric is (3757056/3245056), Route is External Vector metric: Minimum bandwidth is 1544 Kbit Total delay is 82000 microseconds Reliability is 255/255 Load is 1/255 Minimum MTU is 1500 Hop count is 7 External data: Originating router is 192.168.1.1 AS number of routes is 0 External protocol is OSPF, external metric is 64 Administrator tag is 0
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Typical EIGRP Failures scenarios:
1. One way link
2. Mismatched Parameters
3. Query boundary too large
4. Duplicate router-idHello
ping 224.0.0.10
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EIGRP Caveats:
1. auto-summary • Enabled/Disabled?
2. Redistribution metric into EIGRP• MUST be specified
3. Routes advertised to a neighbor1. Only if EIGRP in Routing Table2. Only the best routes
172.16.1.0/24
172.16.2.0/24
192.168.1.0/24
172.16.3.0/24
Discontiguous
Classful Boundary
OSPF
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OSPF Hello
OSPF Neighborship States
Troubleshooting Neighborship Issues
Common Misconceptions
Common Issues.
AGENDA
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OSPF Hello
• Hello Interval
• Dead Interval
• Subnet Mask
• Area ID
• Authentication
• Optional Capabilities - eg. Stub
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Neighborship states
• Down
• INIT - Initiated (Multicast)
• 2-WAY - See ourself in the neighbor Hello (Multicast)
• Exstart - Master/Slave (Unicast)
• Exchange - Exchanging DBD (Unicast)
• Loading - LSR - LSU - Exchange LSA’s (Unicast)
• Full
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Lab Topology:
R1R2
R3
R4
R5
R6 R7
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Neighborship Issue
Neighbor not seen –• Hello Parameters mismatch.• Multicast Issues.
Neighbor stuck in Exstart –• MTU mismatch.• Unicast Issue.
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Common Caveats:
• Summary LSA is not summarisation.
• Distribute-list out doesn’t work.
• Checking the LSA in the wrong database (checking intra-area route in show ip ospf database)
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Other issues:
• 2-way with all the neighbors (no DR)
• Not full will all the neighbors• expected, DR-BDR are full with all the neighbors. • DROthers are only full with DR-BDR
• Advertising router is not reachable (not pingable)could be expected if RID is not advertised.
- RID is just a name.
Thank you.