Mailing List Archive

[nsp] IPv6 in L2TP Virtual-Access interfaces
Dear All,

I'm currently in the process of permitting some test users to obtain
native IPv6 connection over their ADSL lines. The ADSL lines are built
this way :

CPE/PC --[PPPoE/PPPoA]--> DSLAM --[ATM]--> BAS (LAC) --[L2TP]--> LNS

The good news is : IPV6CP is working fine and link-local addresses are
exchanged. For example here is the output of a FreeBSD machine connected
with the "userland" ppp (not the kernel pppd) using PPPoE as transport
protocol :

tun0: flags=8051<UP,POINTOPOINT,RUNNING,MULTICAST> mtu 1492
inet6 fe80::201:3ff:fe41:f096%tun0 -->
fe80::250:bff:fe56:1800%tun0 prefixlen 128 scopeid 0x9
inet 194.158.127.3 --> 194.117.192.173 netmask 0xffffffff
Opened by PID 4199

In this case fe80::250:bff:fe56:1800 is the link-local address of the LNS,
a 7200 running 12.2(11)T. A ping from the client to the LNS' link-local is
ok. The next part is for the LNS to learn the global unicast aggregatable
address of the client using neighbor discovery (and the client to learn
the LNS' one). This is where there is a problem : it seems that the
Virtual-Template interface (and of course the Virtual-Access cloned from
that Virtual-Template) are note joining the neighbor discovery multicast
group :

Virtual-Access3 is up, line protocol is up
IPv6 is enabled, link-local address is FE80::250:BFF:FE56:1800
...
Global unicast address(es):
2001:860:0:1::1, subnet is 2001:860:0:1::/64
Joined group address(es):
FF02::1
FF02::2
MTU is 1480 bytes
ICMP error messages limited to one every 0 milliseconds
...

The interface should be in the FF02::1:FF56:1800 and FF02::1:FF00:1 groups
to learn ND advertisements.

My question is : is ND the right way to do or is there any other machanism
(setting some specific attributes using cisco av-paris in radius for
example) to exchange IPv6 global unicast addresses over a PPP connection ?

Thanks,
Best Regards,
Antoine.

--
Antoine Versini
IP Networks Project Manager / T-Online France - Club-Internet
Re: [nsp] IPv6 in L2TP Virtual-Access interfaces [ In reply to ]
Antoine Versini <vox@t-online.fr> writes:

> This is where there is a problem : it seems that the
> Virtual-Template interface (and of course the Virtual-Access cloned from
> that Virtual-Template) are note joining the neighbor discovery multicast
> group :

Just a wild guess: have you tried "no ipv6 nd suppress-ra"?

Robert
Re: [nsp] IPv6 in L2TP Virtual-Access interfaces [ In reply to ]
On 21 Sep 2002, Robert Kiessling wrote:

> Antoine Versini <vox@t-online.fr> writes:
>
> > This is where there is a problem : it seems that the
> > Virtual-Template interface (and of course the Virtual-Access cloned from
> > that Virtual-Template) are note joining the neighbor discovery multicast
> > group :
>
> Just a wild guess: have you tried "no ipv6 nd suppress-ra"?

My fault, I did not show configuration of the Virtual-Template. That
statement is set and the client station recieve answers to ICMP6 "router
solicitation" queries.

The problem seems to be : neighbor discovery does not operate over
Virtual-Access...

Regards,
Antoine.
Re: [nsp] IPv6 in L2TP Virtual-Access interfaces [ In reply to ]
Hi,

On Sat, Sep 21, 2002 at 07:59:55PM +0200, Antoine Versini wrote:
> My fault, I did not show configuration of the Virtual-Template. That
> statement is set and the client station recieve answers to ICMP6 "router
> solicitation" queries.
>
> The problem seems to be : neighbor discovery does not operate over
> Virtual-Access...

As far as I remember, the whole "IPv6 on dialup/pptp/l2tp interfaces"
stuff is only in early field test so far (but works very nice :) ).

You might want to contact ipv6-support@cisco.com to get access to
the EFT beta images. Right now they all seem to be at IETF, though,
so it might take some time to get a response.

gert

--
USENET is *not* the non-clickable part of WWW!
//www.muc.de/~gert/
Gert Doering - Munich, Germany gert@greenie.muc.de
fax: +49-89-35655025 gert.doering@physik.tu-muenchen.de