OSPF packets

Intra-area - O
Inter-area - O IA (Summary routes)
External - O E2 or O E1

Preference order for destinations with multiple routes:

1. Intra-area 
2. Inter-area
3. External E1 (external+internal cost)
4. External E2 (only external cost)

LSA Types:

Type 1 (RL): Router Links.
Type 2 (NL): Network Links.
Type 3 (SL): Summary Links.
Type 4 : ASBR Summary Links.
Type 5 (EL): External Links.

Collection of OSPF Labs

Here are some of the labs I've created when studying for the CCNP Exams:

1. OSPF Network w/ two areas connected to the Backbone Area 0. One of the networks being a Totally Stub Area w/ redundant connections to the backbone. Download Project Files



2. Based on project above, with an extra Area 99 added via a Virtual-Link. Download Project Files



3. Backbone Area on a Point to Multipoint Frame-Relay network. A chance to observe different ospf area types. And also the DR/BDR relations and configurations in two different areas. Download

OSPF Network Types

OSPF Communication:
Multicast 224.0.0.5: All OSPF Neighbors listen
224.0.0.6: Only DR and BDR listen

OSPF Network Types: