ENARSI_Chapter_10.pdf

Chapter 10: Troubleshooting OSPFv3 Instructor Materials CCNP Enterprise: Advanced Routing Chapter 10 Content This chapter covers the following content: Troubleshooting OSPFv3 for IPv6 - This section examines the various commands you can use to troubleshoot OSPFv3 issues. OSPFv3 Trouble Tic...

Chapter 10: Troubleshooting OSPFv3 Instructor Materials CCNP Enterprise: Advanced Routing Chapter 10 Content This chapter covers the following content: Troubleshooting OSPFv3 for IPv6 - This section examines the various commands you can use to troubleshoot OSPFv3 issues. OSPFv3 Trouble Tickets - This section presents trouble tickets that demonstrate how to use a structured troubleshooting process to solve a reported problem. Troubleshooting OSPFv3 Address Families - This section describes the commands you can use to troubleshoot issues related to OSPFv3 address family configurations. OSPFv3 AF Trouble Tickets - This section presents a trouble ticket that demonstrates how to use a structured troubleshooting process to solve a reported problem. © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 2 Troubleshooting OSPFv3 for IPv6 Because OSPFv3 is based on OSPFv2, it presents similar issues when it comes to troubleshooting, with a few minor differences based on IPv6. This section describes show commands that you can use to troubleshoot OSPFv3 neighbor adjacency issues and route issues. © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 3 Troubleshooting OSPFv3 for IPv6 OSPFv3 Troubleshooting Commands Use the show ipv6 protocols command, as shown in Example 10-1, to verify which IPv6 routing protocols are running on a device. Specifically with OSPFv3, you can verify: the process ID (PID) the router ID (RID) the type of router—area border router (ABR) or autonomous system boundary router (ASBR)—the number of areas the router is a member of whether any of the areas are stub areas or NSSAs (not-so-stubby areas) the interfaces participating in the routing process and the area they belong to whether redistribution is occurring © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 4 Troubleshooting OSPFv3 for IPv6 Show IPv6 OSPF Command Use the show ipv6 ospf command, as shown in Example 10-2, to display global OSPFv3 settings. You can verify: the OSPFv3 PID the RID the type of router—ABR or ASBR—various timers and statistics the number of areas on the router, and the type of area—normal, stub, or NSSA the reference bandwidth the parameters related to the different areas configured on the router (for example, whether area authentication is enabled, whether the area is a stub area, a totally stubby area, an NSSA, or a totally NSSA) © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 5 Troubleshooting OSPFv3 for IPv6 Show IPv6 OSPF Commands (Cont.) The command show ipv6 ospf interface brief, as shown in Example 10-3, enables you to verify which interfaces are participating in the OSPFv3 process. With the show ipv6 ospf interface interface_type interface_number command, you can obtain detailed information about the interfaces participating in the OSPF process, as shown in Example 10-4. The show ipv6 ospf neighbor command enables you to verify what routers successfully formed neighbor adjacencies with the local router, as shown in Example 10-5. © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 6 Troubleshooting OSPFv3 for IPv6 Show IPv6 OSPF Commands (Cont.) To verify the LSAs that were collected and placed in the LSDB, you use the show ipv6 ospf database command, as shown in Example 10-6. In this example, R1 has information for Area 0 and Area 1 because it is an ABR. © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 7 Troubleshooting OSPFv3 for IPv6 Show IPv6 Route OSPF Command Notice in Example 10-6 that there are two new LSA types beyond the types listed in Table 8-4 in Chapter 8: the link (Type 8) LSA and the intra-area prefix (is also known as Type 9) LSA. Table 10-2 defines these two LSAs for OSPFv3. To verify the OSPFv3 routes that have been installed in the routing table, use the show ipv6 route ospf command, as shown in Example 10-7. In this case, R1 only knows about an external OSPFv3 route, which is the default route, and two inter- area routes (routes outside the area but still within the OSPFv3 domain). © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 8 Troubleshooting OSPFv3 for IPv6 Show IPv6 Interface Command Use the show ipv6 interface interface_type interface_id command, as shown in Example 10-8, when troubleshooting OSPFv3 issues to verify whether the interface is listening to the multicast group addresses FF02::5 (all OSPFv3 routers) and FF02::6 (OSPFv3 DR/BDR). You can also verify the MTU and whether there are any IPv6 ACLs applied to the interface that might be blocking OSPFv3 packets or packets sourced from/destined to link-local addresses. © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 9 OSPFv3 Trouble Ticket This section presents two trouble tickets related to the topics discussed so far in this chapter. The purpose of these trouble tickets is to show a process that you can use when troubleshooting in the real world or in an exam environment. Both of the trouble tickets in this section are based on the topology shown in Figure 10-1. © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 10 OSPFv3 Trouble Tickets Trouble Ticket 10-1 Problem: The network was recently updated to reduce the number of LSAs that cross the WAN link from R1 to the Branch site. The only LSA that is supposed to be permitted is a Type 3 LSA about a default route. However, reports indicate that more Type 3 LSAs are being sent from R1 to Branch. Your troubleshooting begins by verifying the problem with the show ipv6 route ospf command on Branch, as shown in Example 10-9. You confirm that there are more interarea routes than just the default interarea route. Refer to your text for next steps and examples to troubleshoot and resolve this trouble ticket. © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 11 OSPFv3 Trouble Tickets Trouble Ticket 10-2 Problem: Branch users are complaining that they are unable to access any resources outside the Branch office. You access Branch and issue the extended ping command, as shown in Example 10-16, to test connectivity. Connectivity fails. Refer to your text for next steps and examples to troubleshoot and resolve this trouble ticket. © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 12 OSPFv3 Trouble Tickets Trouble Ticket 10-3 Problem: Users in Branch have indicated that they are not able to access any IPv6-enabled resources on the internet, but they can access IPv4-enabled resources. An extended ping issued on Branch to the destination 2001:db8:f::f confirms the issue, as shown in Example 10-33. In addition, you ping 192.0.2.1, and it is successful in confirming connectivity to IPv4- enabled resources. Refer to your text for next steps and examples to troubleshoot and resolve this trouble ticket. © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 13 Troubleshooting OSPFv3 Address Families OSPFv3 address families (AFs) enable you to configure a single process to support both IPv4 and IPv6. In addition, a single database is maintained for IPv4 and IPv6. However, adjacencies are established individually for each AF, and settings can be configured on an AF-by-AF basis. This section shows the commands you can use to troubleshoot an OSPFv3 implementation that uses address families. © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 14 Troubleshooting OSPFv3 Address Families AF Verification Example 10-26 shows a sample OSPFv3 configuration with AFs. The OSPFv3 PID is 10 and is locally significant. Therefore, it does not have to match between neighbors. Any parameter configured under the main router OSPFv3 configuration mode applies to all address families. In this example, the area 23 stub command is configured under the main router OSPFv3 configuration mode; therefore, Area 23 is a stub area for both IPv4 and IPv6 address families. Note that if there are conflicts between configurations in router OSPFv3 configuration mode and AF configuration mode, AF configuration mode wins. © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 15 Troubleshooting OSPFv3 Address Families AF Configurations OSPFv3 interface parameters are still configured in interface configuration mode. If you do not specify the AF (IPv4 or IPv6), the configured parameter applies to all address families. If you apply the configuration to the AF, it applies only to that AF. If a conflict exists, the AF configuration wins. In the GigabitEthernet 0/0 configuration in Example 10-26, notice that the hello interval is configured without an AF specified. Therefore, it applies to both IPv4 and IPv6. However, the hello interval is also configured for the IPv6 AF. Therefore, this configuration prevails for IPv6, and a hello interval of 10 is used; IPv4 uses the hello interval 11. © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 16 Troubleshooting OSPFv3 Address Families Show IP Protocols With OSPFv3 AFs, you can use the show ip protocols and show ipv6 protocols commands, as shown in Example 10-27. © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 17 Troubleshooting OSPFv3 Address Families Show OSPFv3 The output of show ospfv3, as shown in Example 10-28, displays the same information you would find with the show ip ospf and show ipv6 ospf commands. Notice that the IPv4 AF is listed first, followed by the IPv6 AF. © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 18 Troubleshooting OSPFv3 Address Families Show OSPFv3 Interface The output command show ospfv3 interface brief command shows the interfaces participating in the OSPFv3 process for each AF (see Example 10-29). Notice the added column that indicates which AF the interface is participating in. The show ospfv3 interface command enables you to review detailed information about the interface configurations. Example 10-30 displays the IPv4 AF information at the top and the IPv6 AF information at the bottom. © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 19 Troubleshooting OSPFv3 Address Families AF Neighbors To verify the neighbor relationships that have been formed for each AF, issue the command show ospfv3 neighbor, as shown in Example 10-31. The output is presenting the same information as discussed earlier, except this time there are different sections for each AF. To verify the information in the LSDB, you issue the command show ospfv3 database. When using AFs, the OSPFv3 database contains LSAs for both IPv4 and IPv6, as shown in Example 10-32. (The rest of the Example 10-32 is on the next slide.) © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 20 Troubleshooting OSPFv3 Address Families AF Neighbors (Cont.) © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 21 Troubleshooting OSPFv3 Address Families OSPFv3 AF Troubleshooting Tips When troubleshooting OSPFv3 AFs that both OSPF for IPv4 and OSPF for IPv6 use IPv6 to exchange routing information. Therefore, IPv6 unicast routing must be enabled on the router. Also, classic OSPFv2 and the OSPFv3 AFs are not compatible. Therefore, a router using OSPFv3 AFs for IPv4 does not peer with a router using the classic OSPFv2 configuration for IPv4 because they are not compatible. To verify the IPv4 OSPFv3 entries in the routing table, use the show ip route ospfv3 command. To verify the IPv6 OSPFv3 entries in the routing table, use the show ipv6 route ospf command. If you need to perform any debugging for OSPFv3, you can issue the debug ospfv3 command followed by what you want to debug, such as events, packets, hellos, or adj. This turns on the debugging for all AFs. If you want to turn it on only for a specific AF, you need to include the AF in the command. For example, in the command debug ospfv3 ipv6 hello, ipv6 refers to the AF. © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 22 OSPFv3 AF Trouble Ticket This section presents a trouble ticket related to the topics discussed in the preceding section. The purpose of this trouble ticket is to show a process that you can use when troubleshooting in the real world or in an exam environment. This trouble ticket is based on the topology shown in Figure 10-2. © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 23 OSPFv3 AF Trouble Ticket Trouble Ticket 10-3 Problem: Users in Branch have indicated that they are not able to access any IPv6-enabled resources on the Internet, but they can access IPv4-enabled resources. An extended ping issued on Branch to the destination 2001:db8:f::f confirms the issue, as shown in Example 10-33. In addition, you ping 192.0.2.1, and it is successful in confirming connectivity to IPv4- enabled resources. Refer to your text for next steps and examples to troubleshoot and resolve this trouble ticket. © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 24 Prepare for the Exam © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 25 Prepare for the Exam Key Topics for Chapter 10 Description Description Identifying What Can Be Verified for OSPFv3 Sample OSPFv3 configuration with AFs with show ipv6 protocols Identifying What Can Be Verified with show Using show ospfv3 to verify general OSPFv3 ipv6 ospf parameters for AFs Verification during the troubleshooting process Using show ospfv3 interface brief to verify with the show ipv6 ospf interface brief OSPFv3 interfaces command Verification during the troubleshooting process Using show ospfv3 interface to verify details with the show ipv6 ospf interface command of OSPFv3 interfaces Additional OSPF LSAs for OSPFv3 © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 26 Prepare for the Exam Key Terms for Chapter 10 Terms OSPFv3 interface table Virtual Link Backup Designated Router OSPFv3 neighbor table OSPFv3 area border router Stub Area (ABR) OSPFv3 link-state OSPFv3 Autonomous System Totally Stubby Area database (LSDB) Boundary Router (ASBR) Linkstate OSPFv3 NSSA Advertisement (LSA) Dijkstra’s Shortest Path Address Family (AF) Totally NSSA First (SPF) Algorithm OSPFv3 area Designated Router © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 27 Prepare for the Exam Command Reference for Chapter 10 Task Command Syntax Display the IPv4 routing protocols enabled on the device; for OSPFv2, display show ip protocols whether any route filters are applied, the RID, the number of areas the router is participating in, the types of areas, the maximum paths for load balancing, the network area command, the interfaces explicitly participating in the routing process, passive interfaces, routing information sources, and the AD Display the IPv6 dynamic routing protocols enabled on the device; for show ipv6 protocols OSPFv3, display the PID, the RID, the number of areas, the type of areas, the interfaces participating in the routing process, and redistribution information Display general OSPF parameters, including the PID, the RID, the reference show ipv6 ospf bandwidth, the areas configured on the router, the types of areas (stub, totally stubby, NSSA, and totally NSSA), and area authentication Display the OSPF routes that have been installed in the IPv4 routing table show ipv6 ospf interface brief Display detailed information about the interfaces participating in the OSPF show ipv6 ospf interface process, including the interface IPv4 address and mask, area ID, PID, RID, network type, cost, DR/BDR, priority, and timers © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 28 Prepare for the Exam Command Reference for Chapter 10 (Cont.) Task Command Syntax Display the OSPF devices that have formed a neighbor adjacency with the show ipv6 ospf neighbor local router Display the OSPF routes that have been installed in the IPv4/IPv6 routing show ipv6 route table Display general OSPFv3 parameters for IPv4 and IPv6 address families, show ospfv3 including the PID, the RID, the reference bandwidth, the areas configured on the router, the types of areas (stub, totally stubby, NSSA, and totally NSSA), and area authentication Display the interfaces that are participating in the OSPFv3 process and the AF show ospfv3 interface brief they are participating in Display detailed information about the interfaces participating in the OSPFv3 show ospfv3 interface address families, including interface IPv4 and IPv6 addresses, area ID, PID, RID, network type, cost, DR/BDR, priority, and timers Display the OSPFv3 neighbor adjacencies that have been formed for each AF show ospfv3 neighbor Display the OSPF link-state database show ipv6 ospf database © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 29 Prepare for the Exam Command Reference for Chapter 10 (Cont.) Task Command Syntax Display the OSPFv3 link-state database show ospfv3 database Display real-time information related to the exchange of OSPF hello packets; debug {ip | ipv6} ospf hello debug useful for identifying mismatched OSPF timers and mismatched OSPF area ospfv3 {ip | ipv6} hello types Display the transmission and reception of OSPF packets in real time debug {ip | ipv6} ospf packet debug ospfv3 {ip | ipv6} packet Display real-time updates about the formation of an OSPF adjacency; useful debug {ip | ipv6} ospf adj debug for identifying mismatched area IDs and authentication information ospfv3 {ip | ipv6} adj Display real-time information about OSPF events, including the transmission debug {ip | ipv6} ospf events and reception of hello messages and LSAs; might be useful on a router that debug ospfv3 {ip | ipv6} events appears to be ignoring hello messages received from a neighboring router © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 30