OSPF Areas, Part 2, Normal and Stub Areas

Welcome back to our series on OSPF areas. Click here for Part 1 of the series. It is time to focus on normal areas and stub areas in this post. Recall our topology:

We have gone to R1 and created a prefix ( using a loopback interface. We run RIP version 2 on this interface and redistribute this into OSPF Area 0. What should this create on R3 in Area 11 (a normal OSPF area)? That’s right  – a Type 5 LSA for an External prefix. Let us examine the OSPF database on R3 now and the accompanying IP routing table:
R3#show ip ospf database

            OSPF Router with ID ( (Process ID 1)

  Router Link States (Area 11)

Link ID         ADV Router      Age         Seq#       Checksum Link count         1216        0x80000002 0x00023C 1         1215        0x80000002 0x00C075 1

  Net Link States (Area 11)

Link ID         ADV Router      Age         Seq#       Checksum         1215        0x80000001 0x003577

  Summary Net Link States (Area 11)

Link ID         ADV Router      Age         Seq#       Checksum         1281        0x80000001 0x0048C4         1241        0x80000001 0x00C79B

  Summary ASB Link States (Area 11)

Link ID         ADV Router      Age         Seq#       Checksum         449         0x80000001 0x0075B0

  Type-5 AS External Link States

Link ID         ADV Router      Age         Seq#       Checksum Tag         456         0x80000001 0x0075AB 0

R3#show ip route

Gateway of last resort is not set is subnetted, 1 subnets
O IA [110/21] via, 00:24:41, FastEthernet0/0 is subnetted, 1 subnets
O IA [110/20] via, 00:24:41, FastEthernet0/0 is subnetted, 1 subnets
O E2 [110/20000] via, 00:11:53, FastEthernet0/0
C is directly connected, FastEthernet0/0
Sure enough, there is the Type 5 prefix in the normal area. And we cannot forget about the LSA Type 4 (Summary ASB Link State). This informs the OSPF domain of the location of the Autonomous System Boundary Router (ASBR). I am sure you have been noticing how some of the LSAs in the database do not translate directly into routing table entries. For example, the LSA Type 4. This is reminiscent of the EIGRP topology table. That protocol sure tries to act link state as well!
OK, well let us see what happens when we convert Area 11 into a STUB AREA. Remember, this is a simple configuration. All we need to do is go to ALL of the routers in the stub area (there can be many), and issue the router configuration command area 11 stub. Now that we have done that, let us examine the databases on R3.
R3#show ip ospf database

            OSPF Router with ID ( (Process ID 1)

  Router Link States (Area 11)

Link ID         ADV Router      Age         Seq#       Checksum Link count         7           0x80000005 0x001A23 1         6           0x80000005 0x00D85C 1

  Net Link States (Area 11)

Link ID         ADV Router      Age         Seq#       Checksum         6           0x80000004 0x004D5E

  Summary Net Link States (Area 11)

Link ID         ADV Router      Age         Seq#       Checksum         33          0x80000001 0x0075C0         33          0x80000003 0x0062AA         33          0x80000003 0x00E181

R3#show ip route

Gateway of last resort is to network is subnetted, 1 subnets
O IA [110/21] via, 00:01:23, FastEthernet0/0 is subnetted, 1 subnets
O IA [110/20] via, 00:01:23, FastEthernet0/0
C is directly connected, FastEthernet0/0
O*IA [110/11] via, 00:01:23, FastEthernet0/0
Wow, things really changed here. Notice the Stub Area effect worked just as advertised in our Core Knowledge studies. The Type 4 and 5 LSAs were removed from the OSPF database! They were replaced with a “special” LSA Type 3. It is special because it is an automatically generated default route by the Area Border Router (ABR).
Join us in the next part of this blog series where we examine the next OSPF area type, the Totally Stubby Area.


About US

Network Bulls is Best Institute for Cisco CCNA, CCNA Security, CCNA Voice, CCNP, CCNP Security, CCNP Voice, CCIP, CCIE RS, CCIE Security Version 4 and CCIE Voice Certification courses in India. Network Bulls is a complete Cisco Certification Training and Course Coaching Institute in Gurgaon/Delhi NCR region in India. Network Bulls has Biggest Cisco Training labs in India. Network Bulls offers all Cisco courses on Real Cisco Devices. Network Bulls has Biggest Team of CCIE Trainers in North India, with more than 90% of passing rate in First Attempt for CCIE Security Version 4 candidates.
  • Biggest Cisco Training Labs in India
  • More than 90% Passing Rate in First Attempt
  • CCIE Certified Trainers for All courses
  • 24x7 Lab Facility
  • 100% Job Guaranteed Courses
  • Awarded as Best Network Security Institute in 2011 by Times
  • Only Institute in India, to provide CCIE Security Version 4.0 Training
  • CCIE Security Version 4 Training available
  • Latest equipments available for CCIE Security Version 4

Network Bulls Institute Gurgaon

Network Bulls Institute in Gurgaon is one of the best Cisco Certifications Training Centers in India. Network Bulls has Biggest Networking Training and Networking courses labs in North India. Network Bulls is offering Cisco Training courses on real Cisco Routers and Switches. Labs of Network Bulls Institute are 24x7 Available. There are many coaching Centers in Delhi, Gurgaon, Chandigarh, Jaipur, Surat, Mumbai, Bangalore, Hyderabad and Chennai, who are offering Cisco courses, but very few institutes out of that big list are offering Cisco Networking Training on real Cisco devices, with Live Projects. Network Bulls is not just an institute. Network Bulls is a Networking and Network Security Training and consultancy company, which is offering Cisco certifications Training as well support too. NB is awarded in January 2012, by Times, as Best Network Security and Cisco Training Institute for the year 2011. Network Bulls is also offering Summer Training in Gurgaon and Delhi. Network Bulls has collaboration with IT companies, from which Network Bulls is offering Networking courses in Summer Training and Industrial Training of Btech BE BCA MCA students on real Live projects. Job Oriented Training and Industrial Training on Live projects is also offered by network bulls in Gurgaon and Delhi NCR region. Network Bulls is also providing Cisco Networking Trainings to Corporates of Delhi, Gurgaon, bangalore, Jaipur, Nigeria, Chandigarh, Mohali, Haryana, Punjab, Bhiwani, Ambala, Chennai, Hyderabad.
Cisco Certification Exams are also conducted by Network Bulls in its Gurgaon Branch.
Network Bulls don't provide any Cisco CCNA, CCNP simulations for practice. They Provide High End Trainings on Real topologies for high tech troubleshooting on real Networks. There is a list of Top and best Training Institutes in India, which are providing CCNA and CCNP courses, but NB has a different image from market. Many students has given me their feedbacks and reviews about Network bulls Institute, but there were no complaints about any fraud from this institute. Network Bulls is such a wonderful place to get trained from Industry expert Trainers, under guidance of CCIE Certified Engineers.

About Blog

This Blog Contains Links shared by sites: Cisco Guides, Dumps collection, Exam collection, Career Cert, Ketam Mehta, GodsComp.co.cc.


Cisco Networking Certifications Training

Cisco Training in Delhi

ccna training in gurgaon. ccnp course institute in gurgaon, ccie coaching and bootcamp training near gurgaon and delhi. best institute of ccna course in delhi gurgaon india. network bulls provides ccna,ccnp,ccsp,ccie course training in gurgaon, new delhi and india. ccsp training new delhi, ccie security bootcamp in delhi.

Testimonials : Network Bulls

My Name is Rohit Sharma and i Have done CCNA and CCNP Training in Gurgaon Center of Network Bulls and it was a great experience for me to study in Network Bulls.

Cisco Networking Certifications

Myself Komal Verma and i took CCSP Training from Network Bulls in Gurgaon. The day i joined Network Bulls, the day i get addicted with Networking Technologies and I thank Mr. Vikas Sheokand for this wonderful session of Networking. :)
I must say that Network Bulls is Best Institute of CCNA CCNP CCSP CCIE Course Training in Gurgaon, New Delhi and in India too.
Komal Verma

About a wonderfull CCIE Training Institute in Gurgaon

I am Kiran shah from New Delhi. I have recently completed my CCNA CCNP & CCIE Training in Gurgaon from Network Bulls and i recommend Network Bulls for Cisco Training in India.

Kiran Shah

Cisco Coaching and Learning Center

Disclaimer: This site does not store any files on its server. I only index and link to content provided by other sites. If you see any file on server that is against copy right you can inform me at (sidd12341 [at] gmail.com). I will delete that materials within two days. This Website is not official Website of any Institute like INE, Network Bulls, IP Expert. Thanks

CCIE Security Version 4

Cisco Finally updated CCIE Security Lab exam blueprint. WSA Ironport and ISE devices are added in CCIE Security Version 4 Lab Exam Syllabus Blueprint. In Updated CCIE Security Version 4 Syllabus blueprint, new technologies like Mobile Security, VoIP Security and IPV6 Security along with Network Security, are added. As in CCIE Security Version 3 blueprint, Cisco had focused on Network Security only, but now as per market demand, Cisco is looking forward to produce Internet gear Security Engineer, not only Network Security engineers.
In CCIE Security Version 4 Bluerpint, Lab Exam is going to be more interested than before. What is Difference in CCIE Security Version 3 and Version 4? Just go through the CCIE Security Version 4 Lab Equipment and Lab Exam Syllabus Blueprints and find out!