OSPFv3 for IPv4 Configuration

Lessons Discussion
1

This topic is to discuss the following lesson:

2

Hello Rene,

Thanks for the good work here.
Hope you will cover some of v5 written topics for OSPF (3.6 f&g) soon.

3

Thanks Leo, if there’s anything you’d like to see just let me know or add your ideas here:

networklessons.com/member-ideas

4

Rene
Great explanation but I have question about ipv6. I am new to ipv6. Since we are dealing with ipv6 and ospfv3.what I understand from the lesson ospf v3 deals with ipv6. Don’t we need to configure ipv6 address on the interfaces. You have configured ipv4 address
Please let me know.

Thanks
Hamood

5

Hamood,
It used to be the case that OSPFv3 dealt exclusively with IPv6. The point of the lesson, however, is to show that this is no longer the case. OSPFv3 (via RFC 5838) now allows you to use it with both IPv4 and IPv6 via the concept of “address families.”

6

Hello
Could you help me know what exactly this command do ?

(config-if)#ospfv3 1 ipv4 area 0

Thank
Sovandara

7

Hello Heng

This command enables OSPFv3 on the interface. Specifically:

* 1 is the process ID
* IPv4 is the version of IP that you want to enable OSPF for. In this case it’s IPv4
* area 0 states that this interface is in area 0.

Note that OSPFv3 is configured on a port by port basis unlike OSPFv2 which is configured by stating the networks that will participate in OSPF with the network commands.

Remember that OSPFv3 supports IPv6 but it is also compatible with IPv4. The above command implement OSPFv3 on an IPv4 network segment.

You can find out more about this command at this Cisco command reference document.

I hope this has been helpful!

Laz

8

There is a typo on the topology diagram. Both interfaces have IP addresses of 192.168.12.2. It leads to this error message on both routers:

*Nov 9 17:15:19.472: %OSPFv3-4-DUP_RTRID_NBR: OSPFv3-1-IPv4 detected duplicate router-id 192.168.12.2 from FE80::5200:FF:FE02:3 on interface GigabitEthernet0/3

Changing the IP address of R1 to be .1 then doing a:

R1#clear ospfv3 process

fixed it.

Michael

11

Hello Michael

Thanks for pointing that out, you are correct, the address of Gi3 of R1 should be 192.168.12.1. I will let Rene know to make the correction.

Thanks again!

Laz

1 Like
12

Hello @michael1,

I just fixed this typo, thanks for letting us know.

Rene

1 Like
13

Hi Rene,

I have a question about the output of the command. In which type of LSA are the ipv4 prefixes announced?. I noticed that in the output that we saw in this lesson the 1.1.1.1/24 prefix doesn’t appear anywhere.

Thanks!

14

Hello Daniel

The output of the show ospfv3 database will not show the actual prefixes being advertised by each LSA. Only the router IDs will appear as shown in the lesson. However, you can use the show ospfv3 database prefix to be shown the LSAs for each specific prefix. There, you will see the IP addresses of the prefixes advertised.

Now it’s also interesting to note that since loopbacks have been created on the routers, you should see those loopbacks being used as the router IDs of the OSPF routers. However, because OSPF was already running when the loopbacks were created, the OSPF process retains the IP addresses of the interfaces as the router IDs. The only way to change this is to clear the OSPF process on both devices.

I hope this has been helpful!

Laz

1 Like
16

any other major and high level changes in OSPFv3 compare to OSPFv2??

Another thing is that , In EIGRP which version support both IPv4 and IPv6 routing ??

17

Hello Narad

Take a look at this note from our new notes repository. There you will find a table that compares the two versions of OSPF.
https://notes.networklessons.com/ospfv2-and-ospfv3-comparison

You can also take a look at this lesson which sheds more light on the subject.

For EIGRP, the designation EIGRPv4 refers to the protocol that supports IPv4, while EIGRPv6 refers to the protocol that supports IPv6. Which one is being run on a Cisco IOS device depends upon the IOS version and the platform. When EIGRP was published in RFC7868 it already included IPv6 support.

I hope this has been helpful!

Laz

18

Hello Laz ,

If we want to configure Ospfv3 for Ipv6 also in the same Topology can we use the same Ospf Process Number “1” for that or we have to use another process Number for Ipv6 ?

19

Hello Mohammad

When using OSPFv3 with both IPv4 and IPv6, you must use the concept of address families. You can configure which address family each OSPFv3 process is to use (IPv4 or IPv6). Note that you can have only one process per address family.

You can find out more information on how to set up an OSPFv3 router to use both IPv4 and IPv6 addresses simultaneously at the following Cisco documentation:

I hope this has been helpful!

Laz

20

Hello again,

I just wanted a little clarification. What is the point of router ospfv3 [proccesid] command? Is it needed to enable ospfv3?

I was playing around in CML with this today and since i cant use a network command here how am I supposed form OSPFv3 adjacencies? I understand if I go into interface config mode and use the ospfv3 1 ipv4 area 0 command on all of them after it would work but then couldn’t I just go straight to using that without doing router ospfv3 [processid]. Or is that required before I can use OSPFv3 interface configuration to start assigning areas.

Is there some command I am forgetting where I can just enable it globally. Once in address-family configuration mode I dont see anything where I could do something similarly to what a network statement would do. I see that with area I can configure stubs or authentication, etc.

Sorry if this is confusing.

21

Hello Cameron

The router ospfv3 [processID] command is necessary simply to initiate the OSPF process on the router. Even if you don’t configure anything under the OSPFv3 configuration mode, it still enables the process. There are many features and mechanisms that are enabled under that configuration mode, but by default, if you just want to enable OSPFv3 adjacencies, then no additional configs are necessary.

Network statements are not used in OSPFv3. If you enable OSPFv3 on an interface, you are essentially saying that the subnet associated with that interface should participate in OSPF.

I hope this has been helpful!

Laz

22

Hi team,
R1 & R2

(config)#interface GigabitEthernet 3
(config-if)#ipv6 enable
(config-if)#ospfv3 1 ipv4 area 0

Is it g3 or g0/2?

23

Hi Vanilson

Yep, that’s a typo, thanks for pointing that out! I’ll let Rene know to make the change…

Laz