As World IPv6 Day (W6D) is approaching, IT people in this city start to think how many users will not be able to access Facebook, Google and Yahoo and what is the overall impact to Hong Kong. If we look at the nature of IPv6 brokenness, it is the behavior of dual-stack clients wrongly select the 6to4 tunnels instead of the native IPv4 path to reach a destination website that is running both native IPv4 and IPv6. Hong Kong is quite lucky as Hurricane Electric (HE) has provided a 6to4 gateway with ample bandwidth. The clients will use 6to4 tunnels to reach HE’s 6to4 gateway and then access Facebook, Yahoo or Google on IPv6 without break. This works on the condition the serving ISPs do not block protocol 41 in their firewalls and access to the anycast addresss 192.88.99.1 is also not restricted. Specifically, any intentional blocking of the anycast network 192.88.99.0/24 in the ISP side should not exist. In other words, the impact to Hong Kong is quite minimal if ISPs are willing to let protocol 41 to pass through.
On checking the number of ASNs advertising 192.88.99.0/24, I notice that there are 33 6to4 gateways in the world. In some other countries where there is no 6to4 gateway, users will experience brokenness on W6D.
In case of complete breakdown of HE’s 6to4 gateway in Hong Kong, there will be about 2500 users with broken access. The figure is based on 0.05 % brokenness estimated by ISOC multiplied by 5 million PC users in Hong Kong. I must say this is an unfounded worry.
How about congestion in 6to4 gateway. This should not be a problem since HE’s 6to4 gateway has a bandwidth of 1 Gbps and if 2500 users access the gateway at the same time, each user can have 400 kbps connection speed.
I think I am the first IT people to analyze the impact of W6D to Hong Kong. I hope my analysis is sound and justifiable.
3 comments:
I think it will impact a lot of people in Australia as well.
When I suggest that we should plan for IPv6 for the next network design, my manager said, not another 2 years until the major telco in Australia support IPv6 in their networks......
How about the users using Teredo ?
No impact for Teredo.
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