Missing OSPF route

[lordnikec]

Hello people, I am configuring a dynamic route using OSPF for the topology in the zip file. I have done it, but Router 3, 4, 5, and 6 can't seem to be able to ping Router 1's Eth1/0. Is this normal for OSPF configuration? Or did I do something wrong? I have been debugging all day and I need help.

[Flavio Miranda]

@lordnikec 

 Are you sure? I am able to ping just fine.

[lordnikec]

Hello there, thanks for helping! But can you ping both 2000:102:2010::1/64 and 2000:103:2010::1/64 at the same time? Are both of these routes shown in Router 3 to 6?

My issue is Router 3 to 6 only show either one of the routes everytime.

[Flavio Miranda]

@lordnikec 

 Yes, I can ping both interfaces from R6.

[lordnikec]

Somehow the issue is gone when I reopened the pka file, but sometimes the issue occurs again, I do not know why is this happening but I guess it is solved...? Anyway thank you for your help, I really appreciate you spending your time for this.

[Flavio Miranda]

It could be some issue/bug with the Packet Tracer but the most important is that your configuration is right. I dont see anything missing.

[Harold Ritter]

Hi @lordnikec ,

I have seen this issue before, where some of the ospf routers are missing some ospf routes. This seems to be related to Packet Tracer as @Flavio Miranda mentioned.

One way I found to make sure this issue doesn't not happen is to configure the transit interfaces (interfaces on which an ospf neighborship is established) as ospf point to point link using the following command.

interface <interface-name>

ipv6 ospf network point-to-point

You will need to restart the packet tracer simulation after configuring that change.

Regards,

[Joseph W. Doherty]

---

@Harold Ritter wrote:

I have seen this issue before, where some of the ospf routers are missing some ospf routes. This seems to be related to Packet Tracer as @Flavio Miranda mentioned.

@Harold Ritter, out of curiosity, for OSPFv2 or OSPFv3 or both?

BTW, I also recommend OSPF p2p when you just have two neighbors on an Ethernet segment.

As anyone who has used PT over the years, which very possibly isn't true for @lordnikec (and that's not meant as a critique), "knows" PT may operate incorrectly (and/or is "missing" features commonly found for in the IOS for the device).

PT is a quite impressive software for its price!  However, if software fidelity is crucially important, you'll need to consider packages like Cisco's CML, or some emulators that run actual IOS binaries.

That said, Cisco, I believe, has improved PT over the years, so it doesn't hurt to try using its latest version (v8.2.2), if not already doing so.

[Joseph W. Doherty]

BTW, when I download an open the PT file in my v8.2.2.0400 I get:

That doesn't provide me a warm and fuzzy feeling.  ; )

[Harold Ritter]

Hi @Joseph W. Doherty ,

> out of curiosity, for OSPFv2 or OSPFv3 or both?

I observed this behaviour specifically for ospfv3.

> BTW, I also recommend OSPF p2p when you just have two neighbors on an Ethernet segment.

This is indeed best practice. The DR election is unnecessary when there is only two neighbors on a given link and the adjacency will form quicker.

Regards,

[Joseph W. Doherty]

---

@Harold Ritter wrote:

> out of curiosity, for OSPFv2 or OSPFv3 or both?

I observed this behaviour specifically for ospfv3.

Thanks.  If I were going to give odds on one of them having issues, it would have been OSPFv3.

---

@Harold Ritter wrote:

> BTW, I also recommend OSPF p2p when you just have two neighbors on an Ethernet segment.

This is indeed best practice. The DR election is unnecessary when there is only two neighbors on a given link and the adjacency will form quicker.

---

Ditto.

[lordnikec]

PC1:
IPV6 Address: 2000:1001:2010:0000::100/64
Gateway: 2000:1001:2010::1

PC2:
IPV6 Address: 2000:2001:2010:0000::100/64
Gateway: 2000:2001:2010::2

PC3:
IPV6 Address: 2000:3001:2010:0000::100/64
Gateway: 2000:3001:2010::3

PC4:
IPV6 Address: 2000:4001:2010:0000::100/64
Gateway: 2000:4001:2010::4

PC5:
IPV6 Address: 2000:5001:2010:0000::100/64
Gateway: 2000:5001:2010::5

PC6:
IPV6 Address: 2000:6001:2010:0000::100/64
Gateway: 2000:6001:2010::6

Router 1:
enable
ipv6 unicast-routing
int f0/0
ipv6 en
ipv6 add 2000:1001:2010:0000::1/64
no sh
int e1/0
ipv6 en
ipv6 add 2000:0102:2010:0000::1/64
no sh
int e1/1
ipv6 en
ipv6 add 2000:0103:2010:0000::1/64
no sh

router 2:
enable
ipv6 unicast-routing
int e1/0
ipv6 en
ipv6 add 2000:0102:2010:0000::2/64
no sh
int f0/0
ipv6 en
ipv6 add 2000:2001:2010:0000::2/64
no sh
int f0/1
ipv6 en
ipv6 add 2000:0203:2010:0000::2/64
no sh

router 3:
enable
ipv6 unicast-routing
int e1/1
ipv6 en
ipv6 add 2000:0103:2010:0000::3/64
no sh
int f0/1
ipv6 en
ipv6 add 2000:0203:2010:0000::3/64
no sh
int f0/0
ipv6 en
ipv6 add 2000:3001:2010:0000::3/64
no sh
int e1/0
ipv6 en
ipv6 add 2000:0304:2010:0000::3/64
no sh

router 4:
enable
ipv6 unicast-routing
int e1/0
ipv6 en
ipv6 add 2000:0304:2010:0000::4/64
no sh
int f0/0
ipv6 en
ipv6 add 2000:4001:2010:0000::4/64
no sh
int f0/1
ipv6 en
ipv6 add 2000:0405:2010:0000::4/64
no sh

router 5:
enable
ipv6 unicast-routing
int f0/1
ipv6 en
ipv6 add 2000:0405:2010:0000::5/64
no sh
int f0/0
ipv6 en
ipv6 add 2000:5001:2010:0000::5/64
no sh
int e1/0
ipv6 en
ipv6 add 2000:0506:2010:0000::5/64
no sh

router 6:
enable
ipv6 unicast-routing
int e1/0
ipv6 en
ipv6 add 2000:0506:2010:0000::6/64
no sh
int f0/0
ipv6 en
ipv6 add 2000:6001:2010:0000::6/64
no sh

OSPF Configuration:
Router 1:
enable
conf te
ipv6 unicast-routing
ipv6 router ospf 1
router-id 1.1.1.1
int f0/0
ipv6 ospf 1 area 0
int e1/0
ipv6 ospf 1 area 0
int e1/1
ipv6 ospf 1 area 0

Router 2:
enable
conf te
ipv6 unicast-routing
ipv6 router ospf 1
router-id 2.2.2.2
int e1/0
ipv6 ospf 1 area 0
int f0/1
ipv6 ospf 1 area 0
int f0/0
ipv6 ospf 1 area 0

Router 3:
enable
conf te
ipv6 unicast-routing
ipv6 router ospf 1
router-id 3.3.3.3
int e1/1
ipv6 ospf 1 area 0
int f0/1
ipv6 ospf 1 area 0
int f0/0
ipv6 ospf 1 area 0
int e1/0
ipv6 ospf 1 area 0

Router 4:
enable
conf te
ipv6 unicast-routing
ipv6 router ospf 1
router-id 4.4.4.4
int e1/0
ipv6 ospf 1 area 0
int f0/0
ipv6 ospf 1 area 0
int f0/1
ipv6 ospf 1 area 0

Router 5:
enable
conf te
ipv6 unicast-routing
ipv6 router ospf 1
router-id 5.5.5.5
int f0/1
ipv6 ospf 1 area 0
int f0/0
ipv6 ospf 1 area 0
int e1/0
ipv6 ospf 1 area 0

Router 6:
enable
conf te
ipv6 unicast-routing
ipv6 router ospf 1
router-id 6.6.6.6
int e1/0
ipv6 ospf 1 area 0
int f0/0
ipv6 ospf 1 area 0

Here are my configurations if needed as reference.