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IPv6 Loopback Best Practices / Routing Issues

Unanswered Question
Sep 13th, 2013
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I have been doing some reading on IPv6 and have read a few different best practices guides and all of them seem to have conflicting information on the best way to assign loopback addresses.


In the end I essentially decided to use /128 on loopback interfaces using globally unique IPv6 space out of a /64 reserved for loopback numbering across our entire network.


The issue I am having now is attempting to get the loopback addresses to route between routers.  I was hoping that I would be able to use the link local IPv6 addresses of the port channel between the routers to route the loopback address information, however, this does not seem to be working in Cisco IOS.  Is this not supported?  Am I doing something wrong?


Relevant Config:


R1:


interface Loopback0

ip address 192.168.32.1 255.255.255.255

ipv6 address yyyy:yyyy:100::10:0:1/128


interface Vlan10

  ip address x.x.x.x x.x.x.x

  ipv6 enable


ipv6 route yyyy:yyyy:100::10:0:2/128 Vlan10 FE80::21D:71FF:FE53:6C00


sh ipv6 int brief outputs: FE80::219:7FF:FEFE:FC00 for Vlan10 interface IP


R2:


interface Loopback0

ip address 192.168.32.2 255.255.255.255

ipv6 address yyyy:yyyy:100::10:0:2/128


interface Vlan10

  ip address x.x.x.x x.x.x.x

  ipv6 enable


ipv6 route yyyy:yyyy:100::10:0:1/128 Vlan10 FE80::219:7FF:FEFE:FC00                   


sh ipv6 int brief outputs: FE80::21D:71FF:FE53:6C00 for Vlan10 interface IP


I can ping the link local ips from each respective router to the other but I cannot ping the loopback interface IPs from the either router to the other.  I can ping the loopback IPs locally on each respective router.


Is this setup not supported?  Is it a bug in our IOS version?  Is this a horrible practice?


Last note:


The routes do appear in the routing tables for each respective router:


sho ipv6 route output:


R1:


LC  yyyy:yyyy:100::10:0:1/128 [0/0]

     via ::, Loopback0

S   yyyy:yyyy:100::10:0:2/128 [1/0]

     via FE80::21D:71FF:FE53:6C00, Vlan10


R2:


S   yyyy:yyyy:100::10:0:1/128 [1/0]

     via FE80::219:7FF:FEFE:FC00, Vlan10

LC  yyyy:yyyy:100::10:0:2/128 [0/0]

     via ::, Loopback0


Any help would be appreciated.

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