Hi, Peter:

Here I want to ask you one question:
If the specified detailed prefix doesn’t exist in the receiver’s route table, 
what the receiver will do when it receives the UPA information of this 
specified prefix?

Aijun Wang
China Telecom

> On Jun 10, 2022, at 23:16, Peter Psenak <[email protected]> wrote:
> 
> Aijun,
> 
>> On 08/06/2022 13:22, Aijun Wang wrote:
>> Hi, Peter:
>> “MAX-Value” metric just indicates the associated prefix will be removed if 
>> it is installed previously, as the same function of premature aging.
>> If the prefix doesn’t exist previously on the receiving router, it will do 
>> nothing when it receives such “MAX-Value” metric advertisements.
>> Thus, it can avoid the misbehavior when receiving the unrecognized TLV that 
>> indicates explicitly the unreachable information, but itself only can’t be 
>> used to trigger the switchover of overlay service on the mentioned 
>> prefix(such LSA will be passed immediately, as described in RFC2328).
> 
> sorry, I don't understand the above. Advertising a prefix with LSInfinity 
> will cause the prefix to become unreachable.
> 
> 
>> In summary, UPA just told the receiver the detailed prefix is missed(but may 
>> still be reached via the summary address),but not the prefix is unreachable.
> 
> and why is that a problem?
> 
>> Combine current two information together can declare clearly the detailed 
>> prefix is unreachable and unsupported router will not have any misbehavior 
>> when they don’t understand the PUA information.
> 
> things as described in UPA draft are sufficient to make prefix unreachable. 
> There will be no misbehavior, as we are using existing mechanism to do so.
> 
> thanks,
> Peter
> 
>> And, when all the routers be upgraded(which are all necessary for both 
>> proposals) to support the PUA information , the UPA information can be 
>> omitted.
>> Aijun Wang
>> China Telecom
>>>> On Jun 7, 2022, at 23:59, Peter Psenak <[email protected]> wrote:
>>> 
>>> Aijun,
>>> 
>>>> On 07/06/2022 17:31, Aijun Wang wrote:
>>>> Hi, Peter:
>>>> The differences between our proposals are just how to indicate the PUA/UPA 
>>>> information along with the advertised prefixes. All other 
>>>> mechanisms/procedures are the same, right?
>>>> Then one simple way for the convergence is just the encoding: Let the 
>>>> unreachable prefixes associated with “prefix originator”(with the value 
>>>> set to NULL”) and also set its metrics to MAX-Value.
>>> 
>>> there is no need to introduce any new encoding. That the whole point of the 
>>> UPA draft. We use existing mechanism.
>>> 
>>> thanks,
>>> Peter
>>> 
>>> 
>>>> Other parts can follow the current PUA drafts, which we have discussed 
>>>> intensively in the list and I think you have no any objections.
>>>> Anyway, to make the UPA mechanism take effect, you will also require the 
>>>> router be upgraded. And the “Max-Value” solution doesn’t necessarily 
>>>> indicate the prefix is lost. We should announce such information 
>>>> explicitly.
>>>> We can also discuss other convergence solutions.
>>>> Aijun Wang
>>>> China Telecom
>>>>>> On Jun 7, 2022, at 20:34, Peter Psenak <[email protected]> wrote:
>>>>> 
>>>>> Hi Aijun,
>>>>> 
>>>>> thanks for your interest in the UPA draft.
>>>>> 
>>>>> I'm not sure what exactly is there in your draft that you would like to 
>>>>> merge. The mechanism that we use in the UPA draft is an existing 
>>>>> mechanism and it avoids the the problems that have been discussed in 
>>>>> context of your draft in the past completely.
>>>>> 
>>>>> thanks,
>>>>> Peter
>>>>> 
>>>>> 
>>>>> 
>>>>>> On 07/06/2022 08:59, Aijun Wang wrote:
>>>>>> Hi, Authors of UPA(Unreachable Prefixes Announcement) draft:
>>>>>> After reading your newly proposed draft 
>>>>>> https://datatracker.ietf.org/doc/draft-ppsenak-lsr-igp-ureach-prefix-announce/
>>>>>>  
>>>>>> <https://datatracker.ietf.org/doc/draft-ppsenak-lsr-igp-ureach-prefix-announce/>,
>>>>>>  we found that the overall aim and procedures in your draft are getting 
>>>>>> closer again to the already intensely discussed PUA/PUAM 
>>>>>> solutions(https://datatracker.ietf.org/doc/html/draft-wang-lsr-prefix-unreachable-annoucement-09
>>>>>>  
>>>>>> <https://datatracker.ietf.org/doc/html/draft-wang-lsr-prefix-unreachable-annoucement-09>).
>>>>>> Regardless to the difference of the two proposals, here we propose to 
>>>>>> converge the solutions, based on the PUA/PUAM draft, as we all know the 
>>>>>> WG has discussed PUA/PUAM draft about two years, there is no reason to 
>>>>>> discuss again the similar procedures and the later work should respect 
>>>>>> the former’s efforts.
>>>>>> If you agree, we can discuss the details of  convergence offline. If you 
>>>>>> don’t agree, we can discuss these solutions openly within the WG list.
>>>>>> Aijun Wang
>>>>>> China Telecom
>>>>> 
>>> 
>>> 
> 
> 

_______________________________________________
Lsr mailing list
[email protected]
https://www.ietf.org/mailman/listinfo/lsr

Reply via email to