[c-nsp] Problem with IPv6 ND over ATM

[Phil Bedard]

ATM does not use link-layer addressing persay, and has no multicast  
support, so in RFC2492 (IPv6 over ATM) the NA does not include a "link- 
layer" option, which is what you are seeing in the debug messages.   
That would normally carry the link layer address for the lower layer  
protocol to use to reach that node, but the IPV6 over LLC/SNAP doesn't  
have support for it.  Since you are using RBE I would think it would  
be something like IPv6 over 802.3 over ATM, and it would work but  
maybe the Cisco doesn't create/process the IPv6 messages that way on  
the interface... My guess at this point is you may be left with manual  
configuration...

Phil


On Jun 11, 2008, at 6:42 AM, Bas Roos wrote:

> 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
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