Laurent - assuming you want aggregation for routing, the ISP DHCPv6 server would have to be configured to recognize that A and B are downstream from the CPE, and therefor should be assigned /64s that somehow aggregate under the /48 assigned to the CPE.
Pushing the responsibility to a DHCPv6 server in the CPE allows the CPE to assign prefixes from its /48 to the links between A and B, and other prefixes to the DHCPv6 server for delegation to A and B.
In the picture below, the CPE would be reponsible for assigning a /64 from its /48 to the links between the CPE and A and B. A and B would request prefix(es) for their downstream links. A might request a /64 if it has only one downstream link, or a shorter prefix if it has more than one downstream link.
A and B could be part of the same organization as the CPE, or part of different organizations. It's not clear whether a link between A and B would be useful or sensible.
If ythere is a link between A and B, there's an issue about whether A or B (or both?) should assign a prefix to that link.
- Ralph
At 10:52 AM 6/2/2004 +0200, [EMAIL PROTECTED] wrote:
Thank you Tony and Christian for your answers.
In my question, I missed the point that the ISP and CPE are in different domain,
so the distribution of the /48 to the CPE is supposed to follow a different policy
than how the /64 are distributed.
And having 2 levels of DHCPv6 PD servers is scalable.
Yes, of course A and B are DHCPv6 clients, and the CPE (in my initial question) was supposed to be a working DHCP relay.
I have other questions based on the same (theorical) network:
ISP (ISP DHCPv6 PD server, gives /48 to the CPE) | | CPE (Customer DHCPv6 PD server, gives /64 prefixes) / \ / \ ---B----A--- | |
How many /64 prefixes A and B are supposed to request (to the CPE), and for what usage ? Only for connectivity with the CPE ?
Does the link between A and B have any sense or are A and B part of different clients / organisations ?
Is there any (private?) network connected to A and B ?
=> In others words, what kind of networks/links are supposed to be connected this CPE when using DHCPv6 PD ?
And now the CPE is a DHCPv6 PD server, it should be able to delegate not only /64 prefixes, right ?
Regards,
Laurent
Tony Hain wrote:
You are asking a question which mixes technology with policy. The simple answer to your question is YES. The complex answer is a function of the policy at the ISP DHCP server. Will it accept requests from A & B? Are you expecting the set of /64's allocated to A & B to be contained within the /48 at the CPE? If so what mechanism enforces that at the DHCP server? (IE: how does the DHCP server associate A or B with the CPE?) What is the point of such a broken deployment model? If the expectation is to allocate a /48 to the CPE using DHCP-PD (which it should be), then put a DHCP server in the CPE and have it delegate /64's from that space. This ensures that A & B get their space from the appropriate point in the hierarchy, as well as distributes the load. Consider that it will not be long before A & B have expanded to ~10^3 devices behind that CPE, multiple the number of CPE by that and figure out how to scale the authentication & association logic for a central DHCP server to ensure everything works as expected. Then reconsider the simplicity of distributing that function to the CPE.
Tony
-----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of [EMAIL PROTECTED] Sent: Tuesday, June 01, 2004 7:12 AM To: [EMAIL PROTECTED]; Ralph Droms Subject: question about DHCPv6 prefix delegation
Hi All,
I have a question about DHCPv6 prefix delegation (RFC 3633).
Given the following network:
ISP (Location of DHCPv6 server) | | CPE /48 / \ / \ ---B----A--- | |
Is it possible to configure the DHCP server to allocate : - a /48 prefix to the CPE node - and several /64 prefixes to the nodes A and B ?
Thank you for any help,
Regards,
Laurent
-- Laurent Cl�vy Alcatel CIT, R&I Voice: +33 (0)1 69 63 18 34 Route de Nozay Fax : +33 (0)1 69 63 13 59 91460 Marcoussis mailto:[EMAIL PROTECTED]
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-- Laurent Cl�vy Alcatel CIT, R&I Voice: +33 (0)1 69 63 18 34 Route de Nozay Fax : +33 (0)1 69 63 13 59 91460 Marcoussis mailto:[EMAIL PROTECTED]
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