1. CCNP 1: Advanced Routing
Multiarea OSPF
Welcome to chapter 6 of the Academy Orientation. This course introduces key components, which include the Academy Community.
CCNP 1: Advanced Routing
Chapter 5

2. Overview OSPF Review Multiarea OSPF Operation and Configuration
Area Types: Stub, Totally Stub, and NSSA
Virtual Links
Monitoring and Verifying Multiarea OSPF
OSPF Pitfalls: “What could possibly go wrong?”
This presentation will address how the Academy Connection cultivates a sense of community.
The Academy Connection fosters an awareness of partnership and teamwork.
New features are addressed to strengthen instructor and student communication.
Communication for instructors, students and administrators is addressed in this section.

3. Open Shortest Path First
OSPF is a scalable link-state protocol that determines the best path between two networks by comparing the aggregate costs of all possible paths.
Extremely scalable
Sends incremental updates
Establishes a relationship between neighbor routers
Hierarchical
Supports VLSM
Local academies will be responsible for deciding whether students may participate in community features.
Students will provide first and last name and address if they are permitted to participate.
An important community feature is the participation in discussion boards.
Please complete the Interactive Activity in target indicator: 6.1.1

4. The OSPF Database Each OSPF-enabled interface is considered a “link”.
All links are assimilated into the SPF database.
show ip ospf database
You too will be assimilated into the collective.
Resistance is futile.

5. OSPF Features Scalability Incremental Updates
OSPF is considered by most to be the 2nd most scalable IP IGP
OSPF is used in both Service Provider and Enterprise networks
Incremental Updates
Fast convergence time
Light on bandwidth
Heavy on router CPU cycles
Local academies will be responsible for deciding whether students may participate in community features.
Students will provide first and last name and address if they are permitted to participate.
An important community feature is the participation in discussion boards.
Please complete the Interactive Activity in target indicator: 6.1.1

6. OSPF Neighbor Relationships
Point-to-point links: OSPF detects and connects to neighboring OSPF routers, and the routers exchange link state databases.
Multiaccess links: OSPF detects and connects to neighboring OSPF routers. A designated Router (DR) and Backup Designated Router (BDR) are elected. The routers exchange link state databases with the DR, and their tables are also sent to the BDR.
Verification/Troubleshooting:
Router#show ip ospf neighbors
If you don’t see a DR, guess what?
For added fun:
Router(config)#alias exec sion show ip ospf neighbors
Local academies will be responsible for deciding whether students may participate in community features.
Students will provide first and last name and address if they are permitted to participate.
An important community feature is the participation in discussion boards.
Please complete the Interactive Activity in target indicator: 6.1.1

7. Hierarchy OSPF is based on a 2-layer hierarchy
Backbone and Non-backbone
An OSPF domain can be divided in areas
Each area has its own link state database
Why?
A user’s name will be displayed with their post as a link to the user’s profile.
Discussion Boards will be displayed on the user’s Home Page

8. What problem are you trying to solve?
5.1.1
What problem are you trying to solve?
Additional community tools include: chats, calendars and polls
Chats are both moderated and unmoderated.
Calendars can be created for events of interest to the community.
Polls can be used for surveys. This might relate to certification materials or a question by individuals.

9. What problem are you trying to solve?
5.1.1
What problem are you trying to solve?
Additional community tools include: chats, calendars and polls
Chats are both moderated and unmoderated.
Calendars can be created for events of interest to the community.
Polls can be used for surveys. This might relate to certification materials or a question by individuals.

10. OSPF Areas An area can contain as many as “50ish” routers
This number varies, based on the number and stability of links and the resources on the routers
Backbone area should be relatively small
Backbone area should consist of stable links
Backbone Area = Area 0 = Teh Princess
Communicating success stories can lend itself for a great experience when sharing with others. This is a new feature. Anytime one shares success, the experience for striving for more becomes exciting.

11. OSPF Areas
Backbone Router: Router with at least one interface in Area 0
Internal Router: Router with all interfaces in the same area
Area Border Router (ABR): Router with interfaces in two or more different areas
Autonomous System Boundary Router (ASBR): Router with at least one interface connected to a non-OSPF domain
Communicating success stories can lend itself for a great experience when sharing with others. This is a new feature. Anytime one shares success, the experience for striving for more becomes exciting.

12. Configuration Area 1 Area 10 Area 0 R1(config)#router ospf 1
R1(config-router)#network area 0
R1(config-router)#network area 10
R1(config-router)#network area 1
What kind of router is R1?
Internal Backbone ABR ASBR
Communicating success stories can lend itself for a great experience when sharing with others. This is a new feature. Anytime one shares success, the experience for striving for more becomes exciting.

13. Configuration Area 1 Area 10 Area 0 R1(config)#router ospf 1
R1(config-router)#network area 0
R1(config-router)#network area 10
R1(config-router)#network area 1
What kind of router is R1?
Backbone ABR
Communicating success stories can lend itself for a great experience when sharing with others. This is a new feature. Anytime one shares success, the experience for striving for more becomes exciting.

14. Configuration R2(config)#router ospf 1
R2(config-router)#network area 0
R2(config-router)#network area 0
R2(config-router)#network area 0
What kind of router is R2?
Internal Backbone ABR ASBR
Communicating success stories can lend itself for a great experience when sharing with others. This is a new feature. Anytime one shares success, the experience for striving for more becomes exciting.

15. Configuration R2(config)#router ospf 1
R2(config-router)#network area 0
R2(config-router)#network area 0
R2(config-router)#network area 0
What kind of router is R2?
Internal Backbone
Look Ma, no diagram!
Communicating success stories can lend itself for a great experience when sharing with others. This is a new feature. Anytime one shares success, the experience for striving for more becomes exciting.

16. Configuration R3(config)#router ospf 1
R3(config-router)#network area 10
R3(config-router)#network area 10
R3(config-router)#network area 10
What kind of router is R3?
Internal Backbone ABR ASBR
Communicating success stories can lend itself for a great experience when sharing with others. This is a new feature. Anytime one shares success, the experience for striving for more becomes exciting.

17. Configuration R3(config)#router ospf 1
R3(config-router)#network area 10
R3(config-router)#network area 10
R3(config-router)#network area 10
What kind of router is R3?
Internal
Communicating success stories can lend itself for a great experience when sharing with others. This is a new feature. Anytime one shares success, the experience for striving for more becomes exciting.

18. Configuration R4(config)#ip route 10.4.0.0 255.255.0.0 serial 0/0
R4(config)#router ospf 1
R4(config-router)#network area 0
R4(config-router)#network area 10
R4(config-router)#network area 10
R4(config-router)#redistribute static
What kind of router is R4?
Internal Backbone ABR ASBR
Communicating success stories can lend itself for a great experience when sharing with others. This is a new feature. Anytime one shares success, the experience for striving for more becomes exciting.

19. Configuration R4(config)#ip route 10.4.0.0 255.255.0.0 serial 0/0
R4(config)#router ospf 1
R4(config-router)#network area 0
R4(config-router)#network area 10
R4(config-router)#network area 10
R4(config-router)#redistribute static
What kind of router is R4?
Backbone ABR ASBR
Communicating success stories can lend itself for a great experience when sharing with others. This is a new feature. Anytime one shares success, the experience for striving for more becomes exciting.

20. Configuration R5(config)#router ospf 1
R5(config-router)#network area 1
R5(config-router)#network area 10
R5(config-router)#network area 10
What kind of router is R5?
Internal Backbone ABR ASBR
Communicating success stories can lend itself for a great experience when sharing with others. This is a new feature. Anytime one shares success, the experience for striving for more becomes exciting.

21. Configuration Every area MUST have at least one link in Area 0.
R5(config)#router ospf 1
R5(config-router)#network area 1
R5(config-router)#network area 10
R5(config-router)#network area 10
What kind of router is R5?
Internal Backbone ABR ASBR
Every area MUST have at least one link in Area 0.
Communicating success stories can lend itself for a great experience when sharing with others. This is a new feature. Anytime one shares success, the experience for striving for more becomes exciting.
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22. OSPF LSA Types
Communicating success stories can lend itself for a great experience when sharing with others. This is a new feature. Anytime one shares success, the experience for striving for more becomes exciting.

23. LSA Types and Routing tables
R1#show ip route ospf
O /8 [110/65] via , 00:04:23, Serial 0/0
O IA /8 [110/65] via , 00:04:23, Serial 0/0
O E /8 [110/65] via , 00:04:23, Serial 0/0
Type 2: O
Type 3: O IA (How to reach ABRs)
Type 4: O IA (How to reach ASBRs)
Type 5: O E1 or O E2

24. OSPF Stub Areas A stub area has only one entry and exit point.
Communicating success stories can lend itself for a great experience when sharing with others. This is a new feature. Anytime one shares success, the experience for striving for more becomes exciting.
A stub area has only one entry and exit point.
Topology changes in other areas do not affect stub areas. The ABR is still the only way out.

25. Stub Areas and LSAs
5.2.2
Communicating success stories can lend itself for a great experience when sharing with others. This is a new feature. Anytime one shares success, the experience for striving for more becomes exciting.

26. Stub vs. Totally Stub Similarities Differences
ABR does not advertise Type 4 or 5 LSAs into the area
There should be no OE1 or OE2 routes in the area
ABR advertises a default route to the internal routers
Neither area can have an ASBR in it
Neither area can be the backbone
Differences
Totally stub does not advertise Type 3 LSAs either
Stub routing table: O, O IA, and default route
Totally stub routing table: O and default route

27. Stub and Totally Stub Configuration
5.4.3
Stub and Totally Stub Configuration
Stub Area
R1(config-router)#area 1 stub
R2(config-router)#area 1 stub
Command must be entered on all routers in the area
Totally Stubby Area
R1(config-router)#area 1 stub no-summary
ABR is configured with stub no-summary
Internal routers are configured with stub
Communicating success stories can lend itself for a great experience when sharing with others. This is a new feature. Anytime one shares success, the experience for striving for more becomes exciting.

28. Solution: Not-So-Stubby Areas (NSSAs) The ASBR originates a Type 7 LSA
Many service providers have OSPF areas that have only one exit point, but the areas contain an ASBR
Solution: Not-So-Stubby Areas (NSSAs)
The ASBR originates a Type 7 LSA
The ABR converts from Type 7 to Type 5
Communicating success stories can lend itself for a great experience when sharing with others. This is a new feature. Anytime one shares success, the experience for striving for more becomes exciting.

29. NSSA Configuration Not-So-Stubby Area Totally Not-So-Stubby Area
R1(config-router)#area 1 nssa
R2(config-router)#area 1 nssa
R2(config-router)#redistribute static
Command must be entered on all routers in the area
ASBR must be configured to inject non-OSPF routes
Totally Not-So-Stubby Area
R1(config-router)#area 1 nssa no-summary
R2(config-router)#area 1 stub
ABR is configured with nssa no-summary
Internal routers are configured with nssa
Communicating success stories can lend itself for a great experience when sharing with others. This is a new feature. Anytime one shares success, the experience for striving for more becomes exciting.

30. Stub and NSSA By default, stub ABRs advertise a default route.
5.6.3
Stub and NSSA
By default, stub ABRs advertise a default route.
By default, NSSA ABRs do not.
To force an NSSA to advertise a default route:
R1(config-router)#area 1 nssa default-information-originate
Communicating success stories can lend itself for a great experience when sharing with others. This is a new feature. Anytime one shares success, the experience for striving for more becomes exciting.

31. Summarizing with OSPF Only ABRs and ASBRs can summarize
5.3.2
Summarizing with OSPF
Only ABRs and ASBRs can summarize
Routes should be summarized as/before they are advertised to Area 0
ABR:
R1(config-router)#area 1 range
ASBR:
R1(config-router)#summary-address
Communicating success stories can lend itself for a great experience when sharing with others. This is a new feature. Anytime one shares success, the experience for striving for more becomes exciting.

32. 5.5.1
Breaking the Area 0 Rule
Every area must have at least one interface on at least one router in Area 0.
Area 0 must be contiguous.
Problem: Mergers
Problem: ExtraNets
Communicating success stories can lend itself for a great experience when sharing with others. This is a new feature. Anytime one shares success, the experience for striving for more becomes exciting.

33. OSPF Virtual Links Virtual links are established by router IDs
R1(config-router)#area 1 virtual-link
R3(config-router)#area 1 virtual-link
Virtual links are established by router IDs
Can be used to join a discontiguous Area 0
Can be used to “tunnel” a remote area to Area 0
Note: YOU SHOULD NOT FIND YOURSELF IN THIS SITUATION.
Communicating success stories can lend itself for a great experience when sharing with others. This is a new feature. Anytime one shares success, the experience for striving for more becomes exciting.

34. OSPF Pitfalls OSPF Path Selection OSPF over NBMA OSPF over DDR
Communicating success stories can lend itself for a great experience when sharing with others. This is a new feature. Anytime one shares success, the experience for striving for more becomes exciting.

35. CCNP 1: Advanced Routing
Multiarea OSPF
Welcome to chapter 6 of the Academy Orientation. This course introduces key components, which include the Academy Community.
CCNP 1: Advanced Routing
Chapter 5