OSPF not working in Cisco Packet Tracer

[Vince Williams]

Hello,

Hope you all can help me understand where I've gone wrong here. I'm using Packet Tracer to study for my ICND2. Practicing ospf virtual links at the moment and things aren't quite working out. I have several routers in area 0 and the link between routers 4 and 5 in area 45. Router 5 has a Loopback in area 5 (5.5.5.5) with no adjacency to area 0. So I created a virtual link across area 45 to give area 5 an adjacency to area 0. The virtual link is up/up and router 5 is now in area 0 as i expected it to be.

The ospf database on Router 4 has the information for 5.5.5.5 in it but it won't add a route to the routing table. 

--------------
I was going to copy and paste some of the show commands I ran for verification but the routers had fallen asleep or something and straight up lost all of their OSPF routes. Reloading all the routers got them to wake back up and now the Router 5 loopback is reachable for all the routers. I suppose Packet Tracer really starves itself for memory, though its using only 50-80 MBs while I've got 4 GBs sitting free. Anyone know how to get Packet Tracer to work better? Or should I just figure out GNS3?

[Edwin Portillo]

Could you share the topology please?

[Vince Williams]

[Edwin Portillo]

Remember that if you are working with multi-area OSPF there should be consistency between the routers that handle the same area, for example:

R1<---->area0<---->R2<---->area1<---->R3

[Martin L]

Where is 4 and 5 ? PT may not support muliti-area ospf setup.
also, VL is not on exam. here is syllabus of ccna

2.4 Configure, verify, and troubleshoot single area and multiarea OSPFv2 for IPv4 (excluding authentication, filtering, manual summarization, redistribution, stub, virtual-link, and LSAs)

2.5 Configure, verify, and troubleshoot single area and multiarea OSPFv3 for IPv6 (excluding authentication, filtering, manual summarization, redistribution, stub, virtual-link, and LSAs)

[Vince Williams]

Thanks for clarifying about VL and stub areas, Those were both in the study guide I'm using, but I think he included extra info he thought would be useful in the real world. Never hurts to know a bit more than needed.

[Giuseppe Larosa]

Hello Vince,

>> Thanks for clarifying about VL and stub areas, Those were both in the study guide I'm using, but I think he included extra info he thought would be useful in the real world. Never hurts to know a bit more than needed.

OSPF stub areas and OSPF NSSA not so stubby areas are commonly used and they are helpful in achieving OSPF scalability by limiting the type of routes sent into each area.

Virtual links are not commonly used, they are used only as a temporary workaround solution to avoid area 0 to become partitioned (as a backup path) or to give an area a logical link to area 0 as in your example.

Virtual links are considered an advanced topic and are often used in CCIE labs combined with other features like OSPF authentication and so on.

But in real world virtual links have to be avoided as much as possible.

Hope to help

Giuseppe

[Martin L]

no problem, have fun labbing!

[Vince Williams]

Edwin,

Right, that's what the virtual link is for, to extend that consistency logically when its not available physically.

[Martin L]

not sure if Virtual link is supported by PT; not likely. is the OSPF Virtual link on exam ? probably not but check syllabus
yes, u should try this in GNS3.

if u doing just routing labs , u should use gns3.