Hi Rene,
This lab is fun
. However, i have two questions, what feature make loopback interfaces appear /32 in the routing table and does this have any benefits?
regards,
michael
OSPF Single Area
Scenario:
AsianFish inc. is expanding their business towards Europe so they need to expand their network as well. You are responsible for the performance of the network and decided that OSPF would be a suitable candidate for a routing protocol. Because the network at this moment is still small, you decided a single area OSPF should be enough. It's up to you to make it work!
Goal:
- All IP addresses have been preconfigured for you.
- The following loopback interfaces have been configured:
HongKong: 1.1.1.1 /24
Amsterdam: 2.2.2.2 /24
Barcelona: 3.3.3.3 /24 - HongKong: Configure OSPF (process-id 1) and advertise all networks by using a single network statement. Use area0
- Amsterdam: Configure OSPF (process-id 1) and advertise all networks by using 2 network statements, area0.
- Barcelona: Configure OSPF (process-id 1) and advertise all networks by using 3 network statements, area0.
- Optional: the loopback interfaces appear as /32's in the routing table, make sure they appear as /24's just as you configured them.
- Amsterdam: change the router-id to 22.22.22.22, make sure you see this change from Barcelona by using show commands.
- Traffic from Barcelona to HongKong should use the link between Amsterdam-Barcelona, use the cost command to achieve this.
- Remove the previous change with the cost-command, achieve the same goal by using the bandwidth command.
- Enable clear-text authentication between Amsterdam and HongKong. Use "vault" as a password.
- Enable MD5 authentication between Barcelona and HongKong. Use "Safe" as a password.
- Change the OSPF timers on the link between Amsterdam and Barcelona so hello packets are being sent every 5 seconds.
- The HongKong router will have access to the Internet in the future, you need to advertise a default route in OSPF so Amsterdam and Barcelona will send traffic for unknown networks to HongKong.
It took me 1000s of hours reading books and doing labs, making mistakes over and over again until I mastered all the protocols for CCNA.
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Comments (24)
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mikodongo 2011-09-22 13:06:52
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ReneMolenaar 2011-09-22 15:54:57Hi Michael,
If you are working on this lab I'm guessing you are studying for CCNA?
OSPF uses multiple "network types". You will learn about those in CCNP. One of them is "loopback" and OSPF will always advertise a loopback as /32. Type the show ip ospf interface loopback0 command and it will show you the OSPF network type.
In a way it makes sense because there is nothing more than a single IP address on a loopback interface. Even though you configure a /24 you won't find 200+ IP addresses there.
It will save you some address space (we don't care about that all that much with private IP address space) but it could be useful when you play with most specific routing.
Good luck!
Rene
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oaljohi 2011-12-31 14:19:56I want to thank you to give us small review in OSPF. I have forgot the LOOPBACK and Authentication and how to control them.
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ReneMolenaar 2012-01-02 12:00:35
Thanks Omar!
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Affy888 2012-04-07 13:00:46Hi Rene . Earlier there was an option to download the PDF. Its no longer available. Have you removed all the PDFs?
thanks
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ReneMolenaar 2012-06-18 12:24:44
Hi Affy,
The PDF plugin that generates PDF files from articles was/is really buggy. I would like to add the feature but it's a pain to implement it
Rene
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chihtai 2012-06-15 04:36:17Bought one of your books and found reading and practicing the labs on this website to be a great help!
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ReneMolenaar 2012-06-18 12:25:02
Thanks for sharing this message and good to hear that it's useful to you
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boubou2012 2012-06-25 14:52:32Hello Rene
Nice Lab
But I came across a small problem I wonder if you can help
when I do a
R2#sh ip ospf neighbor
Nothing appear
Did you came across this problem before?
Thanks for your reply
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ReneMolenaar 2012-06-27 08:28:03
There are many things that could go wrong so OSPF doesn't establish the "neighbor adjacency". On a fastethernet network it's probably because you don't have the correct network commands.
Do a "show ip protocols" to see which networks are enabled for OSPF. Also use a "show ip ospf interface fastethernet" to check if it's enabled for the particular interface.
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boubou2012 2012-06-28 12:08:25
Thanks for you reply Rene
The probleme is solved
I had to restart the program (GNS3)thanks again
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BilalBhatti 2012-07-11 09:21:08
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jack3 2012-08-16 07:35:45Hi Rene,
thanks for the great labs
regards,
Jack
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ReneMolenaar 2012-08-24 16:08:41
You are welcome Jack.
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veeroshj 2012-08-29 09:23:04awesome work with the labs
just wanted to check why my outputs differ from yours...
[youtube vid 13
3]
Barcelona#sh ip ospf
Routing Process "ospf 1" with ID 3.3.3.3
Start time: 004:38.244, Time elapsed: 00:53:23.192
Supports only single TOS(TOS0) routes
Supports opaque LSA
Supports Link-local Signaling (LLS)
Supports area transit capability
Router is not originating router-LSAs with maximum metric
Initial SPF schedule delay 5000 msecs
Minimum hold time between two consecutive SPFs 10000 msecs
Maximum wait time between two consecutive SPFs 10000 msecs
Incremental-SPF disabled
Minimum LSA interval 5 secs
Minimum LSA arrival 1000 msecs
LSA group pacing timer 240 secs
Interface flood pacing timer 33 msecs
Retransmission pacing timer 66 msecs
Number of external LSA 0. Checksum Sum 0x000000
Number of opaque AS LSA 0. Checksum Sum 0x000000
Number of DCbitless external and opaque AS LSA 0
Number of DoNotAge external and opaque AS LSA 0
Number of areas in this router is 1. 1 normal 0 stub 0 nssa
Number of areas transit capable is 0
External flood list length 0
Area BACKBONE(0)
Number of interfaces in this area is 3 (1 loopback)
Area has no authentication
SPF algorithm last executed 000:55.988 ago
SPF algorithm executed 24 times
Area ranges are
Number of LSA 6. Checksum Sum 0x03BDD8
Number of opaque link LSA 0. Checksum Sum 0x000000
Number of DCbitless LSA 0
Number of indication LSA 0
Number of DoNotAge LSA 0
Flood list length 0I went through each step but the show output still differs..
apart from the above everything works fine, just confused with show ip ospf command
V
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ReneMolenaar 2012-09-09 10:39:09
The minimum LSA interval is nothing to worry about, it's probably different for some IOS versions. Normally it's not something we tinker with.
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grengo 2012-09-05 19:20:50what is meant by these..?? plz help
advertise all networks by using a single network statementadvertise all networks by using 2 network statements
advertise all networks by using 3 network statements
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ReneMolenaar 2012-09-09 10:39:28
I explain it in the video, you'll see how and why I implement this.
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grengo 2012-09-14 13:36:41
ok i got it ....thanxxx
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mattlove 2012-10-22 12:29:04i am not sure what i am missing, but i am getting two DR's in this topology. Should you not only have one DR in an area?
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mattlove 2012-10-23 10:20:32
I think i worked this out, you can only have one DR and BDR per shared segment not area. So i have on Barcelona i have fa1/0 as BDR for the 192.168.23.0 network and fa0/0 as DR for the 192.168.13.0 network.
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ReneMolenaar 2012-11-07 13:25:09
The DR/BDR election is PER multi-access segment and not for each area.
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sherief 2012-11-10 12:20:25So wonderful, i completed it successfully
Thanks Rene, you are magician.
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anil2007 2013-05-04 06:47:28Hi Rene,
Thanks a lot, this is wonderful