I have decided to document my notes as I study on my blog. I take in information better when I watch the training video/s and take notes. Hope this helps anyone else studying as well. I need to re-certify all my Cisco Certifications so I have picked CCNP Route because its good to refresh this when not doing a lot of routing at work and also the exam will change in Feb 2020. I will have another 3 years to try and figure out how to attempt the CCIE or maybe move to a different specialisation.
The fundamentals of networking are still very important, even as we begin to automate tasks you still need to understand how a routing protocol works inside and out.
I am already halfway through Chris Bryants CCNP OSPF Fundamentals Route Videos, so will kick off now with his OSPF Stub Areas. Stub Areas in OSPF are useful when having routers that don’t need an entire OSPF database or they don’t have the resource capacity for a full table due to the amount of external LSAs in the network.
LSA Types –
LSA 1 – Router Link States – Each Interface attached to the router for every area
LSA 2 – Sent by DRs Only
LSA 3 – Summary LSA – Generated by ABRs only – Describe Inter Area Routes
LSA 4 – Describe Path to ASBR – Generated by ABRs only
LSA 5- External to OSPF (Redistribution) – Only Generated by ASBR
LSA 7 – Only seen in NSSA
Redistribution –
Command – redistribute connected subnets
- Metric 20
- E2 by Default
- DOES NOT INCLUDE LOCAL METRIC TO ASBR
Stub Areas –
Stub – No Type 5 LSA
Total Stub – No Type 3,4 & 5 – Applied on ABR (no-summary command)
NSSA – No type 5 allowed. LSA Type 7 only from an ASBR, converted to LSA type 5 towards backbone. No default route.
Totally NSSA – Default injected via Type 3.
~Brad.
The Cisco Worker Bee 