[v6ops] Re: I-D Action: draft-ietf-v6ops-cpe-lan-pd-03.txt

[Ted Lemon <[e-mail]>]

It would also make sense to send a new IAID whenever we get a new pd
request and have no remaining prefixes to provide.

Op vr 9 aug 2024 om 08:53 schreef Timothy Winters <[e-mail]>

> Hi Mark and Ted,
>
> I'll add a line asking for a second IA_PD with a unique IAID when sending
> Renew/Rebind messages.
>
> ~Tim
>
> On Fri, Aug 9, 2024 at 7:33 AM Ted Lemon <[e-mail]> wrote:
>
>> The point of always asking for a /48 isn’t to signal something to the isp
>> other than “give me the biggest prefix you are willing to provide.”  If we
>> don’t ask for a /48, we won’t get one.
>>
>> If we ask for additional prefixes, the customer may just never see a
>> problem, so I’m not sure how useful a signal this is, but certainly it will
>> tell the isp if there is demand for narrower prefixes, and that isn’t a bad
>> thing.
>>
>> Op vr 9 aug 2024 om 03:30 schreef Mark Smith <[e-mail]>
>>
>>> Hi,
>>>
>>> On Fri, 9 Aug 2024, 12:20 Ted Lemon, <[e-mail]> wrote:
>>>
>>>> What’s the downside?  :)
>>>>
>>>
>>> The concern I have is that I've seen obscure individual customer faults
>>> float around inside residential help desks for a number of weeks being
>>> looked at by different people, rather than being escalated to network
>>> engineering as soon as they should be. Eventually it might get escalated,
>>> or the customer leaves through frustration.
>>>
>>> For ISPs that aren't willing to give out large prefixes e.g., /60s,
>>> having the CPE ask for additional PD space when it runs out would at least
>>> show up in DHCPv6 PD server logs. That network engineering can directly
>>> look for that, and it would be absolute evidence of what problem the
>>> individual customer is suffering from. It would also be direct evidence to
>>> the ISP that they're not handing out big enough prefixes to customers.
>>>
>>> If an ISP isn't going to honor an IA_PD request for a /48, which I think
>>> would be unlikely for ISPs who aren't already handing out /48s, then I
>>> don't think this ID specifying to always ask for /48s is going to achieve
>>> anything. It won't signal to network engineering that customers are running
>>> out of address space because it will hide that customers are running out.
>>>
>>> Regards,
>>> Mark.
>>>
>>>
>>>
>>>> Op do 8 aug 2024 om 14:36 schreef Timothy Winters <[e-mail]>
>>>>
>>>>> Ted,
>>>>>
>>>>> On Thu, Aug 8, 2024 at 2:28 PM Ted Lemon <[e-mail]> wrote:
>>>>>
>>>>>> I think it's fine to try to get more prefixes if you don't get the
>>>>>> amount you asked for the first time, by adding IA_PDs with different IAIDs
>>>>>> to subsequent requests. However, we should always ask for a /48. How does
>>>>>> the CPE router know how many prefixes it will be asked to provide? If the
>>>>>> ISP doesn't want to provide a /48, it will provide a smaller allocation,
>>>>>> and that's perfectly fine.
>>>>>>
>>>>> I was toying with that idea as well.  Just asking for /48.
>>>>>
>>>>>>
>>>>>> On Thu, Aug 8, 2024 at 2:23 PM Timothy Winters <[e-mail]>
>>>>>> wrote:
>>>>>>
>>>>>>> Hi Mark,
>>>>>>>
>>>>>>> On Wed, Aug 7, 2024 at 7:06 PM Mark Smith <[e-mail]>
>>>>>>> wrote:
>>>>>>>
>>>>>>>> Hi,
>>>>>>>>
>>>>>>>> Apologies for the late comments, I seem to be missing IETF ID
>>>>>>>> announcements and WGLCs (I think trying to read everything out of my
>>>>>>>> Inbox might not be working).
>>>>>>>>
>>>>>>>> I don't think logging a system management error for the below
>>>>>>>> situation is good enough in a residential environment:
>>>>>>>>
>>>>>>>> "LPD-2:
>>>>>>>> The IPv6 CE Router MUST assign a prefix from the delegated prefix as
>>>>>>>> specified by L-2 [RFC7084]. If not enough addresses are available
>>>>>>>> the
>>>>>>>> IPv6 CE Router SHOULD log a system management error."
>>>>>>>>
>>>>>>>> Non-technical residential end-users are very unlikely to look up
>>>>>>>> system error logs if they have a fault, they'll call their ISP's
>>>>>>>> help
>>>>>>>> desk straight away - their ISP is their first port of call for any
>>>>>>>> and
>>>>>>>> all faults that look to be Internet faults.
>>>>>>>>
>>>>>>> In this case I was thinking for the ISP to know that they have
>>>>>>> routers that want to give out IA_PD
>>>>>>> on the LAN and they aren't giving a prefix large enough.
>>>>>>>
>>>>>>> In my experience of residential help desk staff looking up or asking
>>>>>>>> customers to look up system logs for error messages isn't a practice
>>>>>>>> either - and if you look at logs of some of these devices they're
>>>>>>>> very
>>>>>>>> chatty so spotting error messages is time consuming, which is
>>>>>>>> counter
>>>>>>>> to a common helpdesk KPI of customer calls answered per hour.
>>>>>>>>
>>>>>>>> I also think in some cases CPE don't expose system logs - from
>>>>>>>> memory,
>>>>>>>> Google's Nest CE routers don't have a system log available.
>>>>>>>>
>>>>>>> I was thinking about getting system logs from CWMP/USP/NETCONF from
>>>>>>> the ISP.
>>>>>>>
>>>>>>>>
>>>>>>>> It would be better if engineering were somehow directly notified of
>>>>>>>> a
>>>>>>>> customer running out of prefixes and ideally could provide more
>>>>>>>> prefixes automatically. The IA_PD Prefix-Length Hint mechanism would
>>>>>>>> do that.
>>>>>>>>
>>>>>>> I'd had discussions with many ISPs, and only a handful of
>>>>>>> environments with the DHCPv6 server
>>>>>>> honor prefix hints.  Most ISPs for planning purposes have a number
>>>>>>> and that's what they send.
>>>>>>>
>>>>>>>>
>>>>>>>> So I'd suggest updating LPD-2 to:
>>>>>>>>
>>>>>>>> "LPD-2:
>>>>>>>> The IPv6 CE Router MUST assign a prefix from the delegated prefix as
>>>>>>>> specified by L-2 [RFC7084]. If not enough prefixes are available the
>>>>>>>> IPv6 CE Router MUST request the number of required additional
>>>>>>>> prefixes, rounded up to the next shortest prefix length bit
>>>>>>>> boundary,
>>>>>>>> via an additional IA_PD option through the Prefix-Length Hint
>>>>>>>> mechanism [RFC8168]. The second or subsequent IA_PD options are used
>>>>>>>> to avoid a renumbering event where the initial and now too-small
>>>>>>>> Prefix-Delegation prefix would be entirely replaced with a new and
>>>>>>>> single larger Prefix-Delegation prefix. The IPv6 CE Router SHOULD
>>>>>>>> log
>>>>>>>> a system management error."
>>>>>>>>
>>>>>>> For this solution, I have some questions.
>>>>>>>
>>>>>>> Are you proposing that subsequent DHCPv6 messages (Renew, Rebind)
>>>>>>> ask
>>>>>>> for additional IA_PDs, beyond what is currently leased?
>>>>>>>
>>>>>>> OR are you proposing that the CE Router change what it's asking
>>>>>>> DHCPv6 Solicit or Request?
>>>>>>>
>>>>>>>>
>>>>>>>> I'm not entirely convinced that "request the number of required
>>>>>>>> additional prefixes, rounded up to the next shortest prefix length
>>>>>>>> bit
>>>>>>>> boundary" is the right amount of address space the CE should
>>>>>>>> request.
>>>>>>>> Perhaps a simpler mechanism would be to request an additional PD
>>>>>>>> Prefix that is the same size as the initial PD prefix provided by
>>>>>>>> the
>>>>>>>> ISP.
>>>>>>>>
>>>>>>> I like this idea the best.  I think this has the highest chance of
>>>>>>> success, that the DHCPv6 Server is
>>>>>>> configured to give out one size.
>>>>>>>
>>>>>>>>
>>>>>>>> (I understand above is complex to provision and manage on the DHCPv6
>>>>>>>> server side and IPv6 addressing side, however that's the price of
>>>>>>>> treating IPv6 address space as if it was scarce rather than
>>>>>>>> abundant.
>>>>>>>> My advice to residential ISPs is to give out /48s. APNIC had no
>>>>>>>> issues
>>>>>>>> with giving an ISP I worked for a few years ago enough address space
>>>>>>>> for us to give all of our 500K residential customers /48s.)
>>>>>>>>
>>>>>>>> Regards,
>>>>>>>> Mark.
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> On Thu, 8 Aug 2024 at 06:39, <[e-mail]> wrote:
>>>>>>>> >
>>>>>>>> > Internet-Draft draft-ietf-v6ops-cpe-lan-pd-03.txt is now
>>>>>>>> available. It is a
>>>>>>>> > work item of the IPv6 Operations (V6OPS) WG of the IETF.
>>>>>>>> >
>>>>>>>> >    Title:   IPv6 CE Routers LAN Prefix Delegation
>>>>>>>> >    Author:  Timothy Winters
>>>>>>>> >    Name:    draft-ietf-v6ops-cpe-lan-pd-03.txt
>>>>>>>> >    Pages:   7
>>>>>>>> >    Dates:   2024-08-07
>>>>>>>> >
>>>>>>>> > Abstract:
>>>>>>>> >
>>>>>>>> >    This document defines requirements for IPv6 CE Routers to
>>>>>>>> support
>>>>>>>> >    DHCPv6 Prefix Delegation for redistributing any unused
>>>>>>>> prefix(es)
>>>>>>>> >    that were delegated to the IPv6 CE Router.  This document
>>>>>>>> updates RFC
>>>>>>>> >    7084.
>>>>>>>> >
>>>>>>>> > The IETF datatracker status page for this Internet-Draft is:
>>>>>>>> > https://datatracker.ietf.org/doc/draft-ietf-v6ops-cpe-lan-pd/
>>>>>>>> >
>>>>>>>> > There is also an HTMLized version available at:
>>>>>>>> >
>>>>>>>> https://datatracker.ietf.org/doc/html/draft-ietf-v6ops-cpe-lan-pd-03
>>>>>>>> >
>>>>>>>> > A diff from the previous version is available at:
>>>>>>>> >
>>>>>>>> https://author-tools.ietf.org/iddiff?url2=draft-ietf-v6ops-cpe-lan-pd-03
>>>>>>>> >
>>>>>>>> > Internet-Drafts are also available by rsync at:
>>>>>>>> > rsync.ietf.org::internet-drafts
>>>>>>>> >
>>>>>>>> >
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