+- How2pass.com Forums (https://www.how2pass.com/forum)
+-- Forum: CCNA (https://www.how2pass.com/forum/forum-4.html)
+--- Forum: Answer this question (https://www.how2pass.com/forum/forum-11.html)
+--- Thread: QID:NA354 - Incorrect answer & explaination in H2P? (/thread-498.html)
QID:NA354 - Incorrect answer & explaination in H2P? - vtnl241 - 10-26-2010
Hi all,
This question has already been posted but it's not discussed thoroughly, so I re-post it
It seems to me that the correct answer will be "RT2 will obtain a full routing table, including a default route, from RT1".
I've already simulated the question on the lab and the correct one is as above.
Extract configuration on RT1:
router ospf 1
log-adjacency-changes
network 172.16.100.0 0.0.0.3 area 0
network 172.16.100.64 0.0.0.63 area 0
default-information originate
!
ip route 0.0.0.0 0.0.0.0 Serial0/0
!
------------
routing table on RT2
RT2#sh ip route
172.16.0.0/16 is variably subnetted, 3 subnets, 3 masks
O 172.16.100.64/26 [110/65] via 172.16.100.1, 00:02:13, Serial0/0
C 172.16.32.0/22 is directly connected, FastEthernet1/0
C 172.16.100.0/30 is directly connected, Serial0/0
O*E2 0.0.0.0/0 [110/1] via 172.16.100.1, 00:02:13, Serial0/0
RT2#
-------------------
Routing table in RT2 includes default route advertised from RT1 through OSPF.
Looking further into the OSPF database table on RT2 for default route:
RT2#sh ip ospf database external
OSPF Router with ID (3.3.3.3) (Process ID 1)
Type-5 AS External Link States
Routing Bit Set on this LSA
LS age: 497
Options: (No TOS-capability, DC)
LS Type: AS External Link
Link State ID: 0.0.0.0 (External Network Number )
Advertising Router: 2.2.2.2
LS Seq Number: 80000001
Checksum: 0xFEAB
Length: 36
Network Mask: /0
Metric Type: 2 (Larger than any link state path)
TOS: 0
Metric: 1
Forward Address: 0.0.0.
External Route Tag: 1
Which means the default route from RT1 didn't include next hop in its LSA, thus RT2 has no idea
if there will be a loop if it put default route in its routing table.
Would anybody advice?
Thanks,
Peter
Re: QID:NA354 - Incorrect answer & explaination in H2P? - jumbobob - 01-24-2013
I don't know the answer, but this question is very much like (identical to?) NA12 except that NA12 has a very different answer. I'm not sure which one to believe.