TrainSignal Chapter 5, Lecture 6 - OSPF Neighbour Authentication

TrainSignal Chapter 5, Lecture 5 cont... - Route Summarisation

Right, so although we can see the routes, we are unable to reach/talk/ping the routers;

So if we hope over to R1;

Notice, we are only doing 1-WAY route redistribution .... so although the connected routes are being redistributed into the OSPF domain, we are NOT doing this with RIP

TrainSignal Chapter 5, Lecture 5 - Area Summarisation

Here we can see E2 and E1 (non default) routes being redistributed, along with the inter-area routes
notice the below config:

NOTICE, here we specify the area we want to summarise, not what we want to summarise into

neighbourship does not drop

the new routing table:

show ip ospf now shows us:

Right, now next we need to check connectivity :0)

TrainSignal Chapter 5, Lecture 3 - Total Stub Areas and NSSA

Just alittle quick extra carry over thang, from the last lab, notice the default route we have for Area34 has a cost of 11, 10 being the cost of the ethernet segment and 1 the default for the default route, well you can change that my friends:

So we should now see a cost of 30, 10 for the ethernet segment and the default cost of 20 that we specified above:

yeah boi! that works a treat, right ... lets get to work:

Lets jump on R3 and make area 34 a totally stub area (we dont need it on R4)

The no-summary option added to the ABR of the stub area will make this a total stub area, which prevents LSA types 3,4 and 5 flooding into the area.

The ABR is the only router that needs the no-summary option enabled. no-summary doesnt have to be added to the other routers in the area but they still have to be configured as a stub.

awesome, check out that routing table now, lets test connectivity to them loopbacks etc:

all good still :0)

REMEMBER

The stub bit flag ahas to match for the adjacency to form/stay up, so it is fine to have one end configured as a stub and one a total stub as the bit is set, HOWEVER if the routers in the area all did not agree on this then we would have problems.

 

HINT: you need to fully remove the stub configuration not just the stub area no summary!

 pretty kool huh, but krazy name "not-so-stubby total stub" - not as common as the other stubs though, but they are out there!