[Lsr] Questions about draft-ietf-lsr-dynamic-flooding-04

"Gengxuesong (Geng Xuesong)" <gengxuesong@huawei.com> Sat, 09 May 2020 06:25 UTC

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From: "Gengxuesong (Geng Xuesong)" <gengxuesong@huawei.com>
To: "tony.li@tony.li" <tony.li@tony.li>, "sarahchen@arista.com" <sarahchen@arista.com>
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Thread-Topic: [Lsr] Questions about draft-ietf-lsr-dynamic-flooding-04
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Date: Sat, 9 May 2020 06:25:08 +0000
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Subject: [Lsr] Questions about draft-ietf-lsr-dynamic-flooding-04
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Hi Tony, Sarah

Thank you for your work about Flooding Reduction mechanism. I think it is very useful for IGP scalability.
When Sarah giving presentation for draft-chen-lsr-dynamic-flooding-algorithm-00 in LSR interim meeting, I raised a question about how to handle multipoint failure in the flooding topology. I remembered that draft-ietf-lsr-dynamic-flooding-04 was mentioned. I have read this draft, especially section 6.8.11 and temporary flooding relevant content. I think it is a valid method logically. (We have tried to raise some examples to challenge this method, but in all these cases, this method works) Considering that reliability of IGP is crucial for deployment, we are still wondering whether some mathematical proof is necessary (or possible) to guarantee that, in all the possible scenarios, proper convergence could be achieved when using flooding reduction algorithm, just as traditional IGP mechanism. The proof may be case by case depending on the flooding reduction algorithm, but we think even some example or clue about how to do this will be very helpful.

Best Regards
Xuesong