Thank you.

Might another option be something in the RFC 9602 space?  Or a new space
from 5f00::/8 (minus the 9602 prefix)?

On Sat, Oct 18, 2025 at 5:19 PM Rishabh Parekh <[email protected]> wrote:

> Erik,
> Yes, the discard prefix 0100:64 from RFC 6666 can be used. My only
> concerns are in practice Locator prefixes are assigned from /32 or /48
> prefix blocks, and I know some implementations may assume these prefix
> blocks for the LOC portion of SRv6 SIDs. The /64 discard prefix LOC will
> push the FUNCT further in SRv6 SID.
>
> That said, I can certainly add it as an option in addition to ULA.
>
> Rishabh.
>
> On Sat, Oct 18, 2025 at 3:28 PM Erik Kline <[email protected]> wrote:
>
>> This helps, thank you.
>>
>> A ULA is not necessarily non-routable, though.  Would it be possible to
>> use the RFC 6666 discard prefix?
>>
>> On Thu, Oct 16, 2025 at 9:48 PM Rishabh Parekh <[email protected]>
>> wrote:
>>
>>> Erik,
>>>
>>> Reply inline @ [RP]
>>>
>>> On Thu, Oct 16, 2025 at 8:55 PM Erik Kline via Datatracker <
>>> [email protected]> wrote:
>>>
>>>> Erik Kline has entered the following ballot position for
>>>> draft-ietf-bess-mvpn-evpn-sr-p2mp-15: Discuss
>>>>
>>>> When responding, please keep the subject line intact and reply to all
>>>> email addresses included in the To and CC lines. (Feel free to cut this
>>>> introductory paragraph, however.)
>>>>
>>>>
>>>> Please refer to
>>>> https://www.ietf.org/about/groups/iesg/statements/handling-ballot-positions/
>>>> for more information about how to handle DISCUSS and COMMENT positions.
>>>>
>>>>
>>>> The document, along with other ballot positions, can be found here:
>>>> https://datatracker.ietf.org/doc/draft-ietf-bess-mvpn-evpn-sr-p2mp/
>>>>
>>>>
>>>>
>>>> ----------------------------------------------------------------------
>>>> DISCUSS:
>>>> ----------------------------------------------------------------------
>>>>
>>>> # Internet AD comments for draft-ietf-bess-mvpn-evpn-sr-p2mp-15
>>>> CC @ekline
>>>>
>>>> * comment syntax:
>>>>   - https://github.com/mnot/ietf-comments/blob/main/format.md
>>>>
>>>> * "Handling Ballot Positions":
>>>>   -
>>>> https://ietf.org/about/groups/iesg/statements/handling-ballot-positions/
>>>>
>>>> ## Discuss
>>>>
>>>> ### S3.1.2
>>>>
>>>> * "The advertising ingress PE MAY
>>>>    use a non-routable prefix as LOC of the SRv6 Multicast Service SID to
>>>>    prevent packets being routed to it based on the SID."
>>>>
>>>>   Can you clarify what is intended here?  I'm afraid I couldn't figure
>>>> out
>>>>   what is meant by a non-routable prefix to prevent packets being routed
>>>>   to the advertising router.
>>>>
>>>>   Possibly I just don't have the right mental model yet.  Is this for
>>>> some
>>>>   scenario where discarding traffic is desired?
>>>>
>>>>
>>>>
>>> [RP] The use-case is when an SRv6 P2MP tree is shared across two or more
>>> MVPN contexts. In this case, the ingress PE advertises an upstream-assigned
>>> SID (one of End.DTMC4/6 specified in Section 5.21) to identify specific
>>> MVPN context for payload processing at an egress PE (which receives MVPN
>>> customer payload on the shared SRv6 P2MP tree). This upstream assigned SID
>>> is carried in SRH of an IPv6 encapsulated packet from the ingress PE. On
>>> the egress PE, this SID (or specifically FUNCT portion of the SID) should
>>> just be used to derive the MVPN context. If an egress PE mistakenly uses
>>> this SID to forward the packet (by setting it in the IPv6 DA header), the
>>> packet will incorrectly routed back to the ingress PE if the LOC portion of
>>> the SID identifies the ingress PE. To prevent incorrect re-routing using
>>> the SID, the ingress PE may use a non-routable IPv6 prefix (such as Unique
>>> Local Address prefix) as the LOC portion of End.DTMC4/6 SID.
>>>
>>> I hope this answers your question.
>>>
>>>
>>>>
>>>>
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