For the first problem, I can see in routing table the concept of Forward metric, if bandwidth are unequal, first route has :
IR_AS200_AREA1#sh ip route 0.0.0.0 Routing entry for 0.0.0.0/0, supernet Known via "ospf 1", distance 110, metric 100, candidate default path, type NSS A extern 2, forward metric 10 Redistributing via ospf 1 Last update from 193.0.0.2 on Ethernet0, 00:00:00 ago Routing Descriptor Blocks: * 193.0.0.2, from 192.168.108.2, 00:00:00 ago, via Ethernet0 Route metric is 100, traffic share count is 1 If I shut down the ethernet link, the second route goes up : IR_AS200_AREA1#sh ip route 0.0.0.0 Routing entry for 0.0.0.0/0, supernet Known via "ospf 1", distance 110, metric 100, candidate default path, type NSS A extern 2, forward metric 64 Redistributing via ospf 1 Last update from 2.0.0.1 on Serial0, 00:00:00 ago Routing Descriptor Blocks: * 2.0.0.1, from 192.168.108.4, 00:00:00 ago, via Serial0 Route metric is 100, traffic share count is 1 Does the concept of forward metric influence the choose of routes for NSSA ? ""Stephane LITKOWSKI"" a icrit dans le message de news: [EMAIL PROTECTED] > Hi all, > > I have some questions about Type 7 LSA default-routes propagated by ABRs. > Consider a NSSA with two ABRs. Each ABR propagate a default route with a > cost of 100 (commands are : area 1 nssa default-originate & area 1 > default-cost 100). > On a Internal router directly connected to each ABR, I can see that only one > default route is in the routing table : > > O*N2 0.0.0.0/0 [110/100] via 193.0.0.2, Ethernet0 > > But the two LSA are in the database : > > IR_AS200_AREA1#sh ip ospf database nssa-external > > OSPF Router with ID (192.168.108.3) (Process ID 1) > > > Type-7 AS External Link States (Area 1) > > Routing Bit Set on this LSA > LS age: 1702 > Options: (No TOS-capability, No Type 7/5 translation, DC) > LS Type: AS External Link > Link State ID: 0.0.0.0 (External Network Number ) > Advertising Router: 192.168.108.2 > LS Seq Number: 80000001 > Checksum: 0x4F63 > Length: 36 > Network Mask: /0 > Metric Type: 2 (Larger than any link state path) > TOS: 0 > Metric: 100 > Forward Address: 193.0.0.2 > External Route Tag: 0 > > LS age: 318 > Options: (No TOS-capability, No Type 7/5 translation, DC) > LS Type: AS External Link > Link State ID: 0.0.0.0 (External Network Number ) > Advertising Router: 192.168.108.4 > LS Seq Number: 80000003 > Checksum: 0xF37B > Length: 36 > Network Mask: /0 > Metric Type: 2 (Larger than any link state path) > TOS: 0 > Metric: 100 > Forward Address: 2.0.0.1 > External Route Tag: 0 > > My first question is, why does the IR choose one default route and not the > both ? With more investigation, I can see that it prefer the link with the > highest bandwidth. If I increase the bandwidth of the other link, the > nexthop change : > > O*N2 0.0.0.0/0 [110/100] via 2.0.0.1, Serial0 > > if bandwidth are equal, the both routes are introduced : > > O*N2 0.0.0.0/0 [110/100] via 193.0.0.2, Ethernet0 > [110/100] via 2.0.0.1, Serial0 > > Why does it consider cost of the link ? > > My other question is, on the ABR. I can see that the 0.0.0.0 LSA are in the > database. The First one is not computed because selforiginated but why the > other is not computed ? (It's a type 7 LSA , not type 3). > > > Thanks for help. > > -- > Stephane LITKOWSKI > Student in a French computer science school > EPITA Telecom & Network specialization (Paris, FRANCE) > CCNA + CCNP > EMail : [EMAIL PROTECTED] Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=52123&t=52122 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]