Different routing paths between IPv4 and IPv6

[fcz]

Hello HE,

Can someone please explain why IPv4 routing takes a longer path in this case?

IPv6 (Milan-Frankfurt)

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1 13 ms 2 ms <1 ms 10ge12-1.core1.mil2.he.net (2001:470:0:145::1)
2 7 ms 10 ms 13 ms 10ge7-2.core1.zrh1.he.net (2001:470:0:c8::2)
3 21 ms 20 ms 12 ms 10ge10-7.core1.fra1.he.net (2001:470:0:21c::1)
4 12 ms 10 ms 13 ms tserv1.fra1.he.net (2001:470:0:69::2)


IPv4 (Milan-Frankfurt)

Code Select Expand


1 16 ms 25 ms 24 ms 10ge1-1.core1.vie1.he.net (184.105.222.134)
2 28 ms 27 ms 27 ms 100ge14-2.core1.prg1.he.net (72.52.92.185)
3 27 ms 41 ms 27 ms 100ge8-1.core1.fra1.he.net (184.105.213.233)
4 27 ms 27 ms 27 ms tserv1.fra1.he.net (216.66.80.30)


There's a difference of 17ms...  do you know why IPv4 packets from Milan to Frankfurt are routed through Vienna(!!!) when there's a shorter path available? (Zurich->Frankfurt)


Thanks!