Hi,

This text talks about filtering.

I was looking for any text which would indicate that UPA can be a prefix
with any mask.

Thx
R.

On Wed, Sep 24, 2025, 06:44 Ketan Talaulikar <[email protected]> wrote:

> Robert, I didn't see anything in the document that restricts the UPA to a
> /32 or a /128. However, you will find the text below in
> https://www.ietf.org/archive/id/draft-ietf-lsr-igp-ureach-prefix-announce-09.html#section-2
> that may be somewhat related to what you are looking for ?
>
> Implementations MAY limit the UPA generation to specific prefixes, e.g.
> host prefixes, SRv6 locators, or similar. Such filtering is optional and
> MAY be controlled via configuration.
>
> Thanks,
> Ketan
>
>
> On Wed, Sep 24, 2025 at 4:07 AM Robert Raszuk <[email protected]> wrote:
>
>> All,
>>
>> Reading the below I have a tiny question -
>>
>> Can UPA be a (sub)summary route covering in one shot more than one
>> address which went down ? Or is there any mandate in the draft that UPA
>> MUST ALWAYS be /32 or /128 only ?
>>
>> Apologies if I missed an answer to it in the text of the draft.
>>
>> Thx,
>> R.
>>
>>
>>
>>> KT> Section 2 has the following text:
>>>
>>> Implementations MAY limit the UPA generation to specific prefixes, e.g.
>>> host prefixes, SRv6 locators, or similar. Such filtering is optional and
>>> MAY be controlled via configuration.
>>>
>>> It is also RECOMMENDED that implementations limit the number of UPA
>>> advertisements which can be originated at a given time.
>>>
>>> I assume the reason for this is to ensure that in some pathological
>>> cases, there is not a storm of UPAs or a large number of UPAs being
>>> generated. If we consider access, aggregation, and core layers, then at
>>> each progressive level the propagation involves the UPAs of the lower level
>>> of hierarchy being sent towards the core. In this case, the propagating
>>> ABR/ASBRs are also kind of originating from the UPAs from the lower layer
>>> in its LSAs/LSPs. So, shouldn't the same controls/limits apply at those
>>> routers as well? Perhaps consider tweaking the language in the above text
>>> to cover both origination and propagation? I am not looking for mention of
>>> specific knobs.
>>>
>>
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