CCNP (642-902) OSPF Simulation

OSPF is configured on routers Indianapolis and Atlanta. Indianapolis’s S0/0 Interface and Atlanta's S0/1 interface are in Area 0. Atlanta’s Loopback0 interface is in Area 2.

ospf

You task is to configure the following:

  • Portland’s S0/0 interface in Area 1
  • Indianapolis’s S0/1 interface in Area 1
  • Use the appropriate mask such that ONLY Portland’s S0/0 and Indianapolis’s S0/1 could be in Area 1.
  • Area 1 should not receive any external or inter-area routes (except the default route).



To download this lab : https://app.box.com/s/izbu1wcbjxdz32hsa1gx

Answer:

Portland Configuration:

Task 1: Portland’s S0/0 interface in Area 1
Task 3: Use the appropriate mask such that ONLY Portland’s S0/0 and Indianapolis’s S0/1 could be in Area 1.


The Portland’s S0/0 IP Address is 192.168.4.5/30. So, we need to find the network address and wildcard mask of 192.168.4.5/30 in order to configure the OSPF.

IP Address : 192.168.4.5 /30
Subnet Mask : 255.255.255.252

Here subtract 252 from 2565, 256-252 = 4, hence the subnets will 4 increment. Like 0, 4, 8, 12, ...

Lets find the 4th octet of Network Address:

Subnet Network Broadcast
0 0 3
1 4 7
2 8 11
3 12 15
4 16 19
5 ... ...


The 4th octet of IP address (192.168.4.5) belongs to subnet 1 ( 4 to 7).

Network Address : 192.168.4.4
Broadcast Address : 192.168.4.7



Lets find the wildcard mask of /30.

Subnet Mask : (Network Bits – 1’s, Host Bits – 0’s)

/30 11111111 11111111 11111111 11111100
  255 255 255 252


Wildcard Mask : (Network Bits – 0’s, Host Bits – 1’s)

/30 00000000 00000000 00000000 00000011
  0 0 0 3



First check your OSPF Process Number by using the command:

Portland>enable
Portland#show run
<output omitted>
!
router ospf 1
!


Portland>enable
Password:
Portland#
conf t
Portland(config)#router ospf 1


Portland(config-router)#network 192.168.4.4 0.0.0.3 area 1

Task 4: Area 1 should not receive any external or inter-area routes (except the default route).

Portland(config-router)#area 1 stub
Portland(config-router)#end
Portland#copy run start



Indianapolis Configuration:

Indianapolis>enable
Password: cisco
Indianapolis#conf t
Indianapolis(config)#router ospf 1

Task 2: Indianapolis’s S0/1 interface in Area 1

Indianapolis(config-router)#network 192.168.4.4 0.0.0.3 area 1

Task 4: Area 1 should not receive any external or inter-area routes (except the default route).
In order to accomplish Task 4, we must stop LSA Type 5 if we don’t want to send external routes. And if we don’t want to send inter-area routes, we have to stop LSA Type 3 and Type 4. Therefore we have to configure area 1 as a totally stubby area.

Indianapolis(config-router)#area 1 stub no-summary

Indianapolis(config-router)#end
Indianapolis#copy run start


2 Responses so far.

  1. Once you have assembled your own required experience data, it is advisable to surrender your own first plan program with your required settlement. Your pmi Initiate will likely then verify you, you should make sure that all the details usually are proper in addition to concluded, and so they might also make contact with your own sources in order to confirm your own specialist experience.

  2. Anonymous says:

    for task 1, we could also configure ospf per interface ?? please advise.

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