NSSA Default-Information-Originate
NSSA Default-Information-Origin
I would like to know the OSPF area type where we use the command NSS Default-Information-Origin
---On Stub area : we configure all routers inside the are with : Area X Stub
--- On Totally Stub : we configure all routers inside the area with :Area X Stub, and the ABR with Area X Stub Non-Summary
---On NSSA area : We configure all routers inside the are with : Area X NSSA
--- On Totally NSSA: We configure all router inside the are with : Area X NSSA and the ABR with Area X NSSA Non-Summary
However I am not sure how we call the area type where we configure :NSS Default-Information-Origin
Thank you
I would like to know the OSPF area type where we use the command NSS Default-Information-Origin
---On Stub area : we configure all routers inside the are with : Area X Stub
--- On Totally Stub : we configure all routers inside the area with :Area X Stub, and the ABR with Area X Stub Non-Summary
---On NSSA area : We configure all routers inside the are with : Area X NSSA
--- On Totally NSSA: We configure all router inside the are with : Area X NSSA and the ABR with Area X NSSA Non-Summary
However I am not sure how we call the area type where we configure :NSS Default-Information-Origin
Thank you
ASKER
how do you call the Stuby Area where this commane is used :
area X nssa default-information-origin
is it NSSA ot Totally NSSA or it has another name ?
area X nssa default-information-origin
is it NSSA ot Totally NSSA or it has another name ?
It is NSSA.
area X nssa
Totally NSSA is configure with:
area X nssa no-summary
area X nssa
Totally NSSA is configure with:
area X nssa no-summary
ASKER
Because there is another area where you configure all its routers with only : Area X NSSA
I mean you do not configure the ABR with Area X NSSA Deafult-Information-Orgina
I mean you do not configure the ABR with Area X NSSA Deafult-Information-Orgina
ASKER
So there is :
1 - Area X NSSA
Not So Stubby Area
2 - Area X NSSA No-Summary
Totally Not So Stubby Area
3 - Area X NSSA Default-Information-Origin
Not Sure ???
1 - Area X NSSA
Not So Stubby Area
2 - Area X NSSA No-Summary
Totally Not So Stubby Area
3 - Area X NSSA Default-Information-Origin
Not Sure ???
ASKER CERTIFIED SOLUTION
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DEAR,
To understand why we use this command when we configure NSSA in ABR on OSPF configuration " area X nssa default-information originate"
you have to know the types of link state advertisement (LSA) that generated by OSPF routers and exchanged between them to update, the optimum path to the destination.
A quick example
R1 is NSSA ABR
R3 is NSSA ASBR connected to IGRP
Now the IGRP routes will be redistributed to OSPF area 1, then readvertise them with default route Via R3 to all routers in area 1 as LSA type 7 which is called NSSA external and it appears on R3 route table as EX
when the LSA type 7 reached the ABR, R1 will not allow it to pass through by using this command on OSPF process " NSSA default information originated" translates LSA Type 7 into an LSA Type 5 and floods it into the OSPF network and can be seen in the routeing table as OE1 or OE2.
for more information about OSPF LSA see the link below
http://www.firewall.cx/networking-topics/routing/ospf-routing-protocol/1178-ospf-lsa-types-explained.html
or
https://www.cisco.com/c/en/us/support/docs/ip/open-shortest-path-first-ospf/6208-nssa.html
To understand why we use this command when we configure NSSA in ABR on OSPF configuration " area X nssa default-information originate"
you have to know the types of link state advertisement (LSA) that generated by OSPF routers and exchanged between them to update, the optimum path to the destination.
A quick example
R1 is NSSA ABR
R3 is NSSA ASBR connected to IGRP
Now the IGRP routes will be redistributed to OSPF area 1, then readvertise them with default route Via R3 to all routers in area 1 as LSA type 7 which is called NSSA external and it appears on R3 route table as EX
when the LSA type 7 reached the ABR, R1 will not allow it to pass through by using this command on OSPF process " NSSA default information originated" translates LSA Type 7 into an LSA Type 5 and floods it into the OSPF network and can be seen in the routeing table as OE1 or OE2.
for more information about OSPF LSA see the link below
http://www.firewall.cx/networking-topics/routing/ospf-routing-protocol/1178-ospf-lsa-types-explained.html
or
https://www.cisco.com/c/en/us/support/docs/ip/open-shortest-path-first-ospf/6208-nssa.html
ASKER
Thank you Guys
NSSA ASBRs - default-Information originate is added, but ASBR needs to have default route in routing table to be able to advertise default route
NSSA - ABR need command to advertise default route into NSSA (area X nssa default-information-origin
I am not sure that all cases are covered here.