[c-nsp] Relaying the ipv6 pd prefix from ADSL to internal routers

Arie Vayner (avayner) avayner at cisco.com
Sun Oct 17 09:28:35 EDT 2010


Yes, you are pefectly right.
I will try to research it a bit later, and maybe run a quick lab test.

Arie

-----Original Message-----
From: George Manousakis [mailto:george at mang.gr] 
Sent: Sunday, October 17, 2010 13:55
To: Arie Vayner (avayner); cisco-nsp at puck.nether.net
Subject: RE: [c-nsp] Relaying the ipv6 pd prefix from ADSL to internal
routers

Arie,

Thanks for your reply.

How could that work? I must assign the /48 prefix on a #2 general-prefix
in
order to be able to assign multiple lans on different interfaces on #2.
This
information exist only in atm/dialer interface dhcp client of #1.

In order to talk about relay (in general) there has to be a configured
server. The only server that gives prefixes is the isp, which of course
will
never answer the same /48 prefix from a relay router (#2). I suppose it
would be more logical not to answer at all to #2.

The best way would be to setup the server on #1. And that server could
serve
the prefix and all other information to the #2 (and not only) router via
client or relay configuration. And that works. But on the #1 router
hosted
server you can import only a few information:

cisco(config-dhcpv6)#import ?
  dns-server   Import DNS address
  domain-name  Import Domain name option
  information  Import information refresh option
  nis          Import NIS options
  nisp         Import NISP options
  sip          Import SIP options
  sntp         Import SNTP option

but NOT the pd prefix !!!!

So in older to have an applicable ipv6 configuration there must be a way
to
relay that /48 prefix from isp to inside routers. Or the isp's should
change
their policy and give static ipv6 prefix per subscriber!

And since the second option will probably be chargeable... I want to
find a
way to do the first one.

George 

> -----Original Message-----
> From: Arie Vayner (avayner) [mailto:avayner at cisco.com]
> Sent: Saturday, October 16, 2010 10:07 PM
> To: George Manousakis; cisco-nsp at puck.nether.net
> Subject: RE: [c-nsp] Relaying the ipv6 pd prefix from ADSL to internal
> routers
> 
> George,
> 
> Did you try to configure router#2 as DHCP relay (on its inside side)
> setting the router#1 link local address as the relay server?
> Never tried it, but this would be my next step...
> 
> Arie
> 
> -----Original Message-----
> From: cisco-nsp-bounces at puck.nether.net
> [mailto:cisco-nsp-bounces at puck.nether.net] On Behalf Of George
> Manousakis
> Sent: Saturday, October 16, 2010 17:31
> To: cisco-nsp at puck.nether.net
> Subject: [c-nsp] Relaying the ipv6 pd prefix from ADSL to internal
> routers
> 
> Let's say that I have an adsl router (#1) connected to an ipv6 isp
> provider.
> 
> 
> 
> Via DHCPv6 I could get a dynamic /48 prefix on my internet router, and
> I
> could use it wherever I want to on #1 since I have the /48 prefix
> matched on
> a general-prefix variable. That way I can have 2^16 /64 lans on router
> #1.
> 
> 
> 
> What if I want is to relay that specific /48 prefix to another router
> (#2)
> that has an Ethernet connection with router #1 in order to serve ipv6
> lans
> on router #2. The interface of #2 that is connected on #1 gets an ipv6
> address with a prefix of /64 and #2 gets ipv6 internet connectivity
but
> no
> other interfaces can be configured because the prefix of the isp is
not
> known to #2.
> 
> 
> 
> Its seems to me to a very common case scenario but I haven't found any
> configuration example.
> 
> You can configure a dhcp server of #1 but you can only announce dns,
> domain
> and STATIC local ipv6 pools. I want to announce the dynamic ipv6 pool
> that
> is stored on #1 and is assigned from the ISP.
> 
> 
> 
> How can I do that???
> 
> 
> 
> Thanks in advance
> 
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