[c-nsp] Problem with IPv6 ND over ATM

[Bas Roos]

Dear All,

I am trying to implement IPv6 in our network, which was going pretty 
well untill I ran into a little problem when trying to get IPv6 to work 
natively for our DSL customers.

We have a 7206VXR NPE-G2 on our network side, and for testing purposes a 
877-W on the customer side. They have been configured as followed (note 
that these routers do not exchange IPv6 routing information with the 
rest of the network or the internet yet, so I just used two IPv6 
addresses I found in an example configuration):

7206:
interface ATM2/0.756 point-to-point
  description Test line
  ! Removed IP address because i don't believe it is needed for solving 
this problem
  ip address x.x.x.x x.x.x.x
  ip access-group ACL-VPI2-VCI756 in
  atm route-bridged ip
  atm route-bridged ipv6
  no atm enable-ilmi-trap
  ipv6 address 3FFE:1111:2222:1003::72/64
  snmp trap link-status
  pvc 2/756
   vbr-nrt 8000 8000
   encapsulation aal5snap

877:
interface ATM0.35 point-to-point
  description WAN
  ! Removed IP address because i don't believe it is needed for solving 
this problem
  ip address x.x.x.x x.x.x.x
  ip nat outside
  ip virtual-reassembly
  atm route-bridged ip
  atm route-bridged ipv6
  pvc 0/35
   encapsulation aal5snap
  !
  ipv6 address 3FFE:1111:2222:1003::45/64

The problem is: we can't ping from each router to the other using it's 
IPv6 address (IPv4 works fine).

When doing a little debugging, I noticed the following logs on the 877 
using 'debug ipv6 nd':

*Apr  6 16:09:30.071: ICMPv6-ND: DELETE -> INCMP: 3FFE:1111:2222:1003::72
*Apr  6 16:09:30.071: ICMPv6-ND: Sending NS for 3FFE:1111:2222:1003::72 
on ATM0.35
*Apr  6 16:09:30.083: ICMPv6-ND: Received NA for 3FFE:1111:2222:1003::72 
on ATM0.35 from 3FFE:1111:2222:1003::72
*Apr  6 16:09:30.083: ICMPv6-ND: NA has no link-layer option
*Apr  6 16:09:31.071: ICMPv6-ND: Sending NS for 3FFE:1111:2222:1003::72 
on ATM0.35.
*Apr  6 16:09:31.083: ICMPv6-ND: Received NA for 3FFE:1111:2222:1003::72 
on ATM0.35 from 3FFE:1111:2222:1003::72
*Apr  6 16:09:31.083: ICMPv6-ND: NA has no link-layer option
*Apr  6 16:09:32.071: ICMPv6-ND: Sending NS for 3FFE:1111:2222:1003::72 
on ATM0.35
*Apr  6 16:09:32.083: ICMPv6-ND: Received NA for 3FFE:1111:2222:1003::72 
on ATM0.35 from 3FFE:1111:2222:1003::72
*Apr  6 16:09:32.083: ICMPv6-ND: NA has no link-layer option.
*Apr  6 16:09:33.071: ICMPv6-ND: INCMP deleted: 3FFE:1111:2222:1003::72
*Apr  6 16:09:33.071: ICMPv6-ND: INCMP -> DELETE: 3FFE:1111:2222:1003::72

(this sequence repeats a couple of times, depending on the amount of 
pings I send).

The problem seems to get fixed (I can ping) when I put a static ipv6 
neighbor entry in the 877:

ipv6 neighbor 3FFE:1111:2222:1003::72 atm0.35 0018.b987.4b38

I have done some searching on google for the problem I noted in the log 
'NA has no link-layer option', which I think is the cause of this 
problem (I don't get this log line on the 7206), but haven't found any 
answers that solve my problem. I have also been trying to find some 
example configurations for IPv6 using ATM interfaces, but besides the 
most examples being about PPPoA, the examples that do fit my situation, 
don't show any configuration settings I am missing or did wrong.

I hope there is someone here who can give me a push in the right 
direction (either with my problem, or with the best location to find a 
good solution).

Please excuse me if I made a huge configurtion error in my IPv6 
configuration, or with my mail to this list, because both is quite new 
to me, still ;)

Thanks in advance!

Bas Roos