CCNP Route Lab 8-5, IPv6 Troubleshooting Lab

CCNP Route Lab 8-5, IPv6 Troubleshooting Lab

Topology

ccnp-route-lab-ipv6-troubleshooting-lab

Objective

  • Troubleshoot and correct issues in an IPv6 topology.

Background
In this lab, you troubleshoot existing configurations to get a working topology. Copy and paste the initial configurations from this lab into the routers. Some of these configurations have intentional errors introduced. Your goal is to troubleshoot and correct any problems in the scenario that prevent full IPv6 connectivity. Full IPv6 connectivity means every address in the scenario is reachable from every router. If you do not know where to start, try pinging remote addresses and see which ones are reachable by either manually performing pings or using a Tcl script.

Note: This lab uses Cisco 1841 routers with Cisco IOS Release 12.4(24)T1 and the Advanced IP Services image c1841 -advipservicesk9-mz.124-24.T1 .bin. You can use other routers (such as a 2801 or 2811) and Cisco IOS Software versions if they have comparable capabilities and features. Depending on the router model and Cisco IOS Software version, the commands available and output produced might vary from what is shown in this lab.

Required Resources

  • 4 routers (Cisco 1841 with Cisco IOS Release 12.4(24)T1 Advanced IP Services or comparable)
  • Serial and console cables

Requirements

  1. Use the IPv6 addressing scheme shown in the diagram.
  2. All interfaces must be in OSPFv3 area 0.
  3. The router IDs are manually configured with the initial configurations.
  4. Do not use static routes, default routes, or routing protocols other than OSPFv3.
  5. All IPv6 addresses in the topology must be reachable from all routers.

Notes: ______________________________________________________________________________
____________________________________________________________________________________

Initial Configurations

Router R1

Router R2

Router R3

Router R4

Router Interface Summary Table

Router Interface Summary
Router Model Ethernet Interface
#1
Ethernet Interface
#2
Serial Interface
#1
Serial Interface
#2
1700 Fast Ethernet 0
(Fa0)
Fast Ethernet 1
(Fa1)
Serial 0 (S0) Serial 0/0/1
(S0/0/1)
1800 Fast Ethernet 0/0
(Fa0/0)
Fast Ethernet 0/1
(Fa0/1)
Serial 0/0/0
(S0/0/0)
Serial 0/0/1
(S0/0/1)
2600 Fast Ethernet 0/0
(Fa0/0)
Fast Ethernet 0/1
(Fa0/1)
Serial 0/0 (S0/0) Serial 0/1 (S0/1)
2800 Fast Ethernet 0/0
(Fa0/0)
Fast Ethernet 0/1
(Fa0/1)
Serial 0/0/0
(S0/0/0)
Serial 0/0/1
(S0/0/1)
Note: To find out how the router is configured, look at the interfaces to identify the type of router and how many interfaces the router has. Rather than list all combinations of configurations for each router class, this table includes identifiers for the possible combinations of Ethernet and serial interfaces in the device. The table does not include any other type of interface, even though a specific router might contain one. For example, for an ISDN BRI interface, the string in parenthesis is the legal abbreviation that can be used in Cisco IOS commands to represent the interface.

IPv6 Troubleshooting Lab – Answer Key (Instructor Version)

Getting Started
This answer key goes over how to troubleshoot the various problems in the lab. One logical place to start is to make sure that all adjacencies are up and all remote addresses are reachable.

Problem 1: R3–R4 adjacency is not forming.
When you start troubleshooting this lab, one place to start is to use the show ipv6 ospf neighbor command to see which adjacencies have formed. The adjacencies between R1 and R2 and between R2 and R3 have formed, but the adjacency between R3 and R4 has not.

Neighbor ID 172.16.4.1 is missing.

You can start by looking into this adjacency. To look at which interfaces OSPFv3 is running on and how they are configured, use the show ipv6 ospf interface command.

The R3 interface serial0/1/0 is configured properly for OSPFv3. However, R4 only shows the loopback interface running OSPFv3. This indicates that there is something wrong with the configuration for the interface or its OSPF configuration. A warning message also appears in the R4 output, which is odd because you should be running OSPFv3 with process number 1 only (as is shown for the loopback interface). However, ignore that for now and look at the interface configuration for R4 serial interface 0/0/0. Remember that OSPFv3 is configured on an interface level.

The IPv6 address looks correct, but there is no ipv6 ospf command to associate this interface with OSPF process ID 1 and Area 0. In the show ipv6 ospf interface command output, the error message refers to router process 100.

A check of the initial configuration shows that it specified process ID 100, instead of the correct process ID 1 for this interface. In addition, the router ID was added for OSPF process 1, so process 100 does not have a router ID and is inactive. Because router process 100 is inactive, it cannot run on interface s0/0/0. That is why it does not display with the show run interface command.

Correct the problem using the following commands. You also have the option of removing the extra OSPF process to “clean up” this inconsistency.

After this, you should see the adjacency form. Optionally, you also could have moved the loopback interface to this process and configured the router ID, but that would have been more work.

Problem 2: R1 loopback interface is unreachable.
Pings from R2 to the R1 loopback interface at IPv6 address FEC0::1:1 fail.

When you run into this issue, a good place to start is to make sure that the adjacency between R1 and R2 is the way it should be.

The above output looks correct. Issue the show ipv6 route command on R2 to view the routing table.

The R2 routing table has no route to the FEC0::1:1/112 network, so it is likely that the problem is on R1. Make sure that OSPFv3 is running on the proper interfaces.

The serial interface appears to be participating in OSPF correctly, but there is nothing listed for the loopback 0 interface. Examine the interface configuration.

The IPv6 address looks correct, but there is no ipv6 ospf statement. Add it, and the address should become reachable.

Tcl Verification Script

Device Configurations (Instructor version)

Router R1

Router R2

Router R3

Router R4

More Resources

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