ipv6, ospfv3 virtual-link

Answered Question
Feb 17th, 2012

Hi  everybody.

I am trying to establish a virtual link between R3 and R2 so area 2 can connect to area 0 and R1 will learn R4's loopback prefix 2000::4/128.

Detail is given below:

R1--s0/0---area 0---s0/0-R2--s0/1--area 1---s0/1-R3--s0/0---area 2-----s0/0--R4

All the above routers's serial interfaces are configured with " ipv6 address autoconfig".

R1's id 1.1.1.1, R2's id 2.2.2.2, R3's id 3.3.3.3,R4's id 4.4.4.4

R4 has loopback address 2000::4/64.

R3 is learning 2000::4/128 from R4.

As expected, R1 is not learning this route because  area 2 is not yet connected to it.

Now if we configure a virtual-link between R3 and R2 ,  R1 should know 2000::4

But for some reasons, R1 is not learning this route.

R3#show ipv6 route

IPv6 Routing Table - 4 entries

Codes: C - Connected, L - Local, S - Static, R - RIP, B - BGP

       U - Per-user Static route, M - MIPv6

       I1 - ISIS L1, I2 - ISIS L2, IA - ISIS interarea, IS - ISIS summary

       O - OSPF intra, OI - OSPF inter, OE1 - OSPF ext 1, OE2 - OSPF ext 2

       ON1 - OSPF NSSA ext 1, ON2 - OSPF NSSA ext 2

       D - EIGRP, EX - EIGRP external

C   2000::/64 [0/0]

     via ::, Loopback3

L   2000::3/128 [0/0]

     via ::, Loopback3

O   2000::4/128 [110/64]

     via FE80::C203:12FF:FEC0:0, Serial0/1

L   FF00::/8 [0/0]

     via ::, Null0

==============================

Below is the virtual-link configured at R3:

pv6 router ospf 1

router-id 3.3.3.3

log-adjacency-changes

area 1 virtual-link 2.2.2.2

!

Virtual-link configuration at R2:

ipv6 router ospf 1

router-id 2.2.2.2

log-adjacency-changes

area 1 virtual-link 3.3.3.3

!

Routing table  at R1 is shown below:

R1#show ipv6 route

OI  2000::3/128 [110/128]

     via FE80::C201:12FF:FEC0:0, Serial0/0

L   FF00::/8 [0/0]

     via ::, Null0

The prefix 2000::4/128 is missing even though virtual-link is configured between R2 and R3.

=======================================================================

Below   I have pasted the configurations:

R1#show running-config

Building configuration.

ipv6 unicast-routing

multilink bundle-name authenticated

interface Serial0/0

no ip address

ipv6 address autoconfig

ipv6 ospf 1 area 0

clock rate 200000

!

ipv6 router ospf 1

router-id 1.1.1.1

log-adjacency-changes

===================================================

R2's config

R2#show running-config

Building configuration...

Current configuration : 1113 bytes

!

version 12.4

!

hostname R2

!

ipv6 unicast-routing

multilink bundle-name authenticated

!

interface Serial0/0

no ip address

ipv6 address autoconfig

ipv6 ospf 1 area 0

clock rate 2000000

interface Serial0/1

no ip address

ipv6 address autoconfig

ipv6 ospf 1 area 1

clock rate 2000000

ipv6 router ospf 1

router-id 2.2.2.2

log-adjacency-changes

area 1 virtual-link 3.3.3.3

================================================

R3's config:

R3#show running-config

Building configuration...

Current configuration : 1195 bytes

!

version 12.4

ipv6 unicast-routing

multilink bundle-name authenticated

!

interface Loopback3

no ip address

ipv6 address 2000::3/64

ipv6 ospf 1 area 1

!

!

interface Serial0/0

no ip address

ipv6 address autoconfig

ipv6 ospf 1 area 1

clock rate 2000000

!

interface Serial0/1

no ip address

ipv6 address autoconfig

ipv6 ospf 1 area 2

clock rate 2000000

!

ipv6 router ospf 1

router-id 3.3.3.3

log-adjacency-changes

area 1 virtual-link 2.2.2.2

==================================================================

R4's config:

R4#show running-config

Building configuration...

Current configuration : 1132 bytes

!

version 12.4

!

ipv6 unicast-routing

multilink bundle-name authenticated

interface Loopback14

no ip address

ipv6 address 2000::4/64

ipv6 ospf 1 area 2

!

interface Serial0/0

no ip address

ipv6 address autoconfig

ipv6 ospf 1 area 2

clock rate 2000000

!

!

ipv6 router ospf 1

router-id 4.4.4.4

log-adjacency-changes

=======================================================================================================

thanks  and have a nice weekend.

I have this problem too.
0 votes
Correct Answer by lgijssel about 2 years 2 months ago

Hi Sarahr,

I have tested your case on GNS3. This provided an intersting result.

On the 3640 with IOS c3640-jk9s-mz.124-16 it did not work, I could not even establish ospf neighbors.

Then I decided to move the lab to a 3745 using IOS Version 12.4(15)T6.

To my surprise it worked almost at once, for some reason the new R1 did not take the modified config but after correcting this GNS-related problem, everthing was ok. This is some output from R1:

R1#sh ipv6 ro

IPv6 Routing Table - 7 entries

Codes: C - Connected, L - Local, S - Static, R - RIP, B - BGP

       U - Per-user Static route, M - MIPv6

       I1 - ISIS L1, I2 - ISIS L2, IA - ISIS interarea, IS - ISIS summary

       O - OSPF intra, OI - OSPF inter, OE1 - OSPF ext 1, OE2 - OSPF ext 2

       ON1 - OSPF NSSA ext 1, ON2 - OSPF NSSA ext 2

       D - EIGRP, EX - EIGRP external

LC  2000::1/128 [0/0]

     via ::, Loopback0

OI  2000::2/128 [110/64]

     via FE80::C201:12FF:FEC0:0, Serial1/0

OI  2000::3/128 [110/128]

     via FE80::C201:12FF:FEC0:0, Serial1/0

OI  2000::4/128 [110/192]

     via FE80::C201:12FF:FEC0:0, Serial1/0

C   2001:2::/64 [0/0]

     via ::, Serial1/0

L   2001:2::2/128 [0/0]

     via ::, Serial1/0

L   FF00::/8 [0/0]

     via ::, Null0

R1#

This implies your config is correct and the problem is with the IOS version or so.

Are you using GNS as well?

I can send the lab via email if you want.

regards,

Leo

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Correct Answer
lgijssel Sat, 02/18/2012 - 02:17

Hi Sarahr,

I have tested your case on GNS3. This provided an intersting result.

On the 3640 with IOS c3640-jk9s-mz.124-16 it did not work, I could not even establish ospf neighbors.

Then I decided to move the lab to a 3745 using IOS Version 12.4(15)T6.

To my surprise it worked almost at once, for some reason the new R1 did not take the modified config but after correcting this GNS-related problem, everthing was ok. This is some output from R1:

R1#sh ipv6 ro

IPv6 Routing Table - 7 entries

Codes: C - Connected, L - Local, S - Static, R - RIP, B - BGP

       U - Per-user Static route, M - MIPv6

       I1 - ISIS L1, I2 - ISIS L2, IA - ISIS interarea, IS - ISIS summary

       O - OSPF intra, OI - OSPF inter, OE1 - OSPF ext 1, OE2 - OSPF ext 2

       ON1 - OSPF NSSA ext 1, ON2 - OSPF NSSA ext 2

       D - EIGRP, EX - EIGRP external

LC  2000::1/128 [0/0]

     via ::, Loopback0

OI  2000::2/128 [110/64]

     via FE80::C201:12FF:FEC0:0, Serial1/0

OI  2000::3/128 [110/128]

     via FE80::C201:12FF:FEC0:0, Serial1/0

OI  2000::4/128 [110/192]

     via FE80::C201:12FF:FEC0:0, Serial1/0

C   2001:2::/64 [0/0]

     via ::, Serial1/0

L   2001:2::2/128 [0/0]

     via ::, Serial1/0

L   FF00::/8 [0/0]

     via ::, Null0

R1#

This implies your config is correct and the problem is with the IOS version or so.

Are you using GNS as well?

I can send the lab via email if you want.

regards,

Leo

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Posted February 17, 2012 at 8:18 PM
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