comments inline: At 09:28 PM 8/3/2002 +0000, bergenpeak wrote: >I'd like to setup a group of routers to be in an OSPF sub-area. >The sub-area will connect to the backbone via one or two >ABRs. All other routers in the sub-area will be ASBRs. >The ABRs will not be ASBRs. > > >From a design perspective, I want to put these routers into >a sub-area so that I can limit the amount of routing information >they need to be aware of. Further, I'd like to limit what >information the backbone routers see regarding these ASBRs. > >Stub and Totally Stubby areas are not an option since the sub- >areas contains ASBRs. > >Configuring the sub-area as an NSSA would help limit the number >of routes in the sub-area (via the ABR nssa no-summary command) >as the sub-area will have just a default, intra-area, and type 7 >routes from the redist process. This is good. > >When the ABR gets the Type 7 LSAs from the ASBRs, it will translate >them into type 5s and flood them throughout the backbone. While it >appears that the backbone routers don't see the ASBRs (via type 4 >LSAs from the ABR), I'd like to determine if it's possible to configure >the ABR to take the type 7s and include these routes instead in the >ABR's type 3 LSA? This would prevent the backbone routers from seeing >the type 5s. Is this possible?
Native to OSPF, you have the ability to translate these LSA's from 7 to 5 or not to. This allows you a small amount of control. You cannot redefine external information as internal on an ABR. You could position a loopback interface in the NSSA area and configured aggregate addresses on it along with the "ip ospf network point-to-point" to enable this network to be advertised as a type 3 toward the backbone. In the real world, I would tend against this. If your intent is to shield non backbone routers from external information, make all areas NSSA and keep your backbone small and capable. >Or, is it possible to perform redist from RIP into OSPF, but >to configure this router to put the routes learned via RIP into it's >type 1 LSA (ie do a redist but prevent the router from being an >ASBR) No. >Thanks for any info. Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=50616&t=50608 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
