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Umar heard a scientist who claimed that only 2% of the live v6 space is pingable today. He will followup with him to decipher what this statement means.
The more important ( in terms of being closer to the behavior of applications and data transfer) item would be to measure tcp rtts (using nping —tcp). Also it appears tcp should work to a larger set of ipv6 hosts than complete thus making it easier to get a larger measurement population