12-11-2005 08:57 AM - edited 03-03-2019 11:12 AM
Hi,
How are the default routes configured in one internal router transmitted to other internal router in an area ? Is it by Type 5 LSA ? Then it should be transmitted to all through the AS as Type 5.Correct me if I am wrong.
Thanks,
Vijay
Solved! Go to Solution.
12-14-2005 03:03 AM
Hi Vijay,
As soon as an OSPF router originates a type-5 LSA that carries the default route it becomes an ASBR, even if it does not originate any other external routes.
If you try this out on a router, you will see that this router will now set the E-bit in its router-LSA (type-1 LSA), signifying that it considers itself to be an ASBR.
Paresh.
12-12-2005 08:51 PM
Hi,
If you inject a default route by means of default-information originate, this will be carried to all non-stub areas in a type-5 LSA.
Paresh.
12-13-2005 02:48 AM
Hi,
For a router to generate Type 5 LSAs, it should be an ASBR.But, how come an ordinary router generate a Type 5 LSA to carry default route ? or Only ASBR router can advertise default route? Correct me if I am wrong.
Thanks,
Vijay
12-13-2005 03:02 AM
Nopes it is not needed for a Router to be ASBR to generate default. An ABR can generate a NSSA Default ROute ( The route will be N1 and N2 not E1 and E2). A totally stub area would have an IA default Route not an external default route which is genrated with default-information originate
12-14-2005 01:32 AM
Hi,
I am not talking about default route generated by ABR(as Type 3 LSA for Stubby Area and as Type 7 LSA for NSSA).I am just talking about the default route generated by a normal router inside a noram area.
I got the document:
http://cisco.com/en/US/tech/tk365/technologies_configuration_example09186a00801ec9f0.shtml
which says 'Default routes injected into a normal area can be originated by any OSPF router'
Thanks,
Vijay
12-14-2005 03:03 AM
Hi Vijay,
As soon as an OSPF router originates a type-5 LSA that carries the default route it becomes an ASBR, even if it does not originate any other external routes.
If you try this out on a router, you will see that this router will now set the E-bit in its router-LSA (type-1 LSA), signifying that it considers itself to be an ASBR.
Paresh.
12-14-2005 04:11 AM
Hi,
Thanks for your explanation.
Thanks,
Vijay
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