OSPF Pop Questions II

NetworkVeteran

DanielH wanted more OSPF scenarios for members seeking their CCNP.

Below is a brilliant physical topology utilizing my years of experience and networking prowess!



Q1. R1's configuration is below. What line(s) must you add to R1's configuration to make OSPF fully-operational?

ipv6 unicast-routing
interface Loopback0
 ipv6 address 1::1/128
 ipv6 ospf 1 area 0
interface Serial0/0
 ipv6 enable
 ipv6 ospf 1 area 0

Q2. R1's configuration is corrected and both routers become neighbors. What is the destination address of R1's hellos?

R1#show ipv6 ospf ne

Neighbor ID     Pri   State           Dead Time   Interface ID    Interface
2.2.2.2           1   FULL/  -        00:00:38    6               Serial0/0

Q3. Which LSA below will contain R1's 1::1/128 address?

R1#show ipv6 ospf database

            OSPFv3 Router with ID (1.1.1.1) (Process ID 1)

                Router Link States (Area 0)

ADV Router      Age         Seq#        Fragment ID  Link count  Bits
1.1.1.1         1347        0x8000000B  0            1           None
2.2.2.2         1337        0x80000005  0            1           None

                Link (Type-[IMG]https://us.v-cdn.net/6030959/uploads/images/smilies/icon_cool.gif[/IMG] Link States (Area 0)

ADV Router      Age         Seq#        Link ID    Interface
1.1.1.1         1442        0x80000002  6          Se0/0
2.2.2.2         1467        0x80000001  6          Se0/0

                Intra Area Prefix Link States (Area 0)

ADV Router      Age         Seq#        Link ID    Ref-lstype  Ref-LSID
1.1.1.1         1347        0x80000001  0          0x2001      0
2.2.2.2         1337        0x80000001  0          0x2001      0
R1#

Q4. Can OSPFv3 carry IPv4 prefixes?

Q5. Does OSPFv3 provide authentication services?

NetworkVeteran

iam4eva, good answers! I updated Q4 based on your feedback. I agree, the wording was originally sloppy.

iamme4eva

I actually deleted my post.....I figured it was unfair to post answers so quick. Better to leave the people studying to work it out and test my own knowledge in private.

Don't wanna spoil people's fun!!!

I enjoyed that though, thanks. Maybe I'll have to devise a scenario to throw up for people.

Danielh22185

Good stuff. I have not given it a hard look yet. Just saw the thread and I will work up my answers before looking at others. I'm turning in for the night though so I'll work on this first thing tomorrow!

Danielh22185

NetworkVeteran wrote: »

DanielH wanted more OSPF scenarios for members seeking their CCNP.

Below is a brilliant physical topology utilizing my years of experience and networking prowess!



Q1. R1's configuration is below. What line(s) must you add to R1's configuration to make OSPF fully-operational?

ipv6 unicast-routing
interface Loopback0
 ipv6 address 1::1/128
 ipv6 ospf 1 area 0
interface Serial0/0
 ipv6 enable
 ipv6 ospf 1 area 0

Q2. R1's configuration is corrected and both routers become neighbors. What is the destination address of R1's hellos?

R1#show ipv6 ospf ne

Neighbor ID     Pri   State           Dead Time   Interface ID    Interface
2.2.2.2           1   FULL/  -        00:00:38    6               Serial0/0

Q3. Which LSA below will contain R1's 1::1/128 address?

R1#show ipv6 ospf database

            OSPFv3 Router with ID (1.1.1.1) (Process ID 1)

                Router Link States (Area 0)

ADV Router      Age         Seq#        Fragment ID  Link count  Bits
1.1.1.1         1347        0x8000000B  0            1           None
2.2.2.2         1337        0x80000005  0            1           None

                Link (Type-[IMG]https://us.v-cdn.net/6030959/uploads/images/smilies/icon_cool.gif[/IMG] Link States (Area 0)

ADV Router      Age         Seq#        Link ID    Interface
1.1.1.1         1442        0x80000002  6          Se0/0
2.2.2.2         1467        0x80000001  6          Se0/0

                Intra Area Prefix Link States (Area 0)

ADV Router      Age         Seq#        Link ID    Ref-lstype  Ref-LSID
1.1.1.1         1347        0x80000001  0          0x2001      0
2.2.2.2         1337        0x80000001  0          0x2001      0
R1#

Q4. Can OSPFv3 carry IPv4 prefixes?

Q5. Does OSPFv3 provide authentication services?

Ouch your hitting on my weakest subject but i'll stab at it.

Q1. R1's configuration is below. What line(s) must you add to R1's configuration to make OSPF fully-operational?

In regards to IPv6 implementations, OSPF isn't operational on the interface that connects the routers. Routing protocols must be enabled on interfaces, instead of via network subnets.

Q2. R1's configuration is corrected and both routers become neighbors. What is the destination address of R1's hellos?

If I am not mistaken it should still go to the address of 2.2.2.2, IPV6 RID address are still written in IPv4 format.

Q3. Which LSA below will contain R1's 1::1/128 address?
LSA 8 will contain Router 1's link local address

Q4. Can OSPFv3 carry IPv4 prefixes?

yes via tunneling methods IPv6-IPv4 tunnels

Q5. Does OSPFv3 provide authentication services?

To be honest, not real sure on this one. I would say yes because I don't see a reason why that should change between the two IP protocols


Now curious to see how I did as I answered from memory without looking ahead.

Danielh22185

BTW great quiz NetVet! I'm happy to be challenged by more as are most people I am sure here.

NetworkVeteran

Question 1 - "router-id x.x.x.x" is the missing line! An OSPFv3 router needs a router ID, and no interfaces are assigned IPv4 addresses, which is what IOS relies on to auto-generate one. As side-notes: (a) OSPFv3 was already enabled on all interfaces via the "ipv6 ospf 1 area 0" command, and "no shutdown" was applied although "show run" doesn't show that.

Question 2 - "FF02::5". OSPF generally multicasts its hellos. Note, this is a point-to-point link, so no DR/BDRs. There are no neighbor statements, nor any indications it's a non-broadcast media where multicasts/broadcasts are impossible.

Question 3 - Type-9: Intra-Area Prefix LSA. Type 8 was a great guess. Note, IOS doesn't treat loopback interfaces like a normal OSPF (point-to-point or broadcast) interface, by default. An article describing what's in each LSA type:
A look at the new LSA types in OSPFv3 with Vyatta and Cisco

Question 4 - Yes! Address-family support was recently added. "I want to say yes because the ipv4 router-id shows in hello packets" Clever! While a RouterID is not to be precise an IP address, they follow the same format, and RouterIDs are often based on IPv4 addresses. "yes via tunneling methods IPv6-IPv4 tunnels" While tunneling would allow an IPv4 PDU to (indirectly) carry an OSPFv3 PDU, they would not allow an OSPFv3 PDU to carry an IPv4 PDU.

Question 5 - No. Straight from the RFC: "Authentication has been removed from the OSPF protocol." While OSPF no longer provides authentication, you can still authenticate your OSPF or RIPng messages, using IPv6 IPSec.

Zartanasaurus

I was curious how you were going to handle the answer to question 4.

Danielh22185

If these are the caliber of questions dealing in IPv6 on the route test I have some more studying to do

NetworkVeteran

Questions 1, 2, and 5 are covered in the first three pages of OSPFv3 Route FLG and further reinforced in the chapter.

Questions 3 is not covered by the Route FLG--besides the book noting types 1, 2, 3, 4, and 5 don't provide this information. That's why I said LSA Type 8 was a great guess, even though LSA Type 9 was the answer.

Question 4 is totally outside the scope of the exam.

Danielh22185

Good info to know. I guessed Type 8 because I knew it had something to do with OSPF and IPv6

Its always great to learn more outside the scope of the Cisco exams.