[161755] in North American Network Operators' Group
Re: Question on Ipv6 address
daemon@ATHENA.MIT.EDU (Owen DeLong)
Tue Mar 26 12:56:43 2013
From: Owen DeLong <owen@delong.com>
In-Reply-To: <BAY170-W1380767C68F8B59D0C8BC3798D00@phx.gbl>
Date: Tue, 26 Mar 2013 09:52:00 -0700
To: Joe <sj_hznm@hotmail.com>
Cc: NANOG <nanog@nanog.org>
Errors-To: nanog-bounces+nanog.discuss=bloom-picayune.mit.edu@nanog.org
On Mar 26, 2013, at 8:39 AM, Joe <sj_hznm@hotmail.com> wrote:
> I'm new to Ipv6 and trying to understanding something about IPv6 in =
service provider network.
> I've got the following questions , could anybody do some helps?
> 1. In a dial-up network (Q-in-Q for each customer who dials in ) =
Should each customer be assigned to ipv6 subnet prefix like /64 unique =
universily? I've read a rfc which stated point-to-point like should =
be assigned /64. But to my
> understanding, in dial-up network , each user should only needed to =
be assigned a single ipv4 address, with wich customer could used in =
his PC or his home router.=20
IPv6 is very different from IPv4.
In IPv6, there should be a /64 assigned to the point to point link over =
which a /48 should be delegated to the customer.
If the customer doesn't have a router and is just attaching a single PC, =
he will not make the Prefix Delegation request and just the =
point-to-point /64 will be adequate.
> 2. In dial-up network, could each vlan's ipv6 link-id be planned =
with its vlan number? if so, IP v6 address confliction could be =
avoided when BAS is assigned a /64 or longer prefix.
Why would you ever assign a longer prefix?
I'm not sure what you mean by "link-id", so I'm not sure what you are =
attempting to resolve here.
> 3. we are testing some BAS with IPv6 accessing, in radius accouting =
packets, there is IP-v6-prefix, Ip-v6-link-id, =
Ip-v6-delegated-prefix. how could dial-up PC's IPv6 address be =
calculated with above information?
It probably can't. Why do you need to?
> 4. should it be necessary to plan different =
IP-v6-prefix(IP-v6-delegated-prefix) for each dial-up customers in BAS?
There are multiple ways to structure this.
If you put all of the customers into a common NBMA network, then you can =
use a single /64 prefix to number all of the link addresses from a given =
BAS to the customer sites. All of the CPE routers will use the same =
address on the BAS as their default gateway.
If you put the customers into individual VLANs, then each VLAN should =
have a /64 prefix assigned to it.
Beyond that, if the customer has a router, you should plan on having a =
/48 delegated prefix for each customer.
> 5. How could delegated IPv6 prefix be used in service provider's =
network? is this useful in dial-up access network?
The delegated prefix isn't used in the service provider's network. It is =
delegated to the customer for them to number their network. It can be =
used by the customer regardless of attachment method, though the low =
speeds of dialup make a complex topology on the far side less likely.
Owen
