IPv6 tunnel (proto 41) filtered during Peak times

Below are ping graphs and mtr output showing complete loss of IPv6 tunnel connectivity coinciding with consumer ADSL peak filtering times.

:'(

IPv6 tunnel connectivity (Fri 17 Dec)

IPv6 tunnel from Entanet (Cambridge) to HE.net (London)

IPv6 packet loss between my edge router and IPv6 remote endpoint:

                                   My traceroute  [v0.73]
hastur (::)                                                         Thu Dec 16 13:08:37 2010
Keys:  Help   Display mode   Restart statistics   Order of fields   quit 
                                                    Packets               Pings
 Host                                             Loss%   Snt   Last   Avg  Best  Wrst StDev
 1. router.ip6                                     0.0%  1002    0.6   0.6   0.6  27.7   1.0
 2. gnomeza-1.tunnel.tserv5.lon1.ipv6.he.net      98.6%  1002   34.0  34.3  33.6  35.6   0.6
IPv6 tunnel connectivity (Thu 16 Dec 0700 - 1300)

IPv4 from Entanet (Cambridge) to HE.net (London)

Excellent IPv4 connectivity between my edge router and IPv6 tunnel broker:

                                   My traceroute  [v0.73]
hastur (0.0.0.0)                                                    Thu Dec 16 13:25:23 2010
Keys:  Help   Display mode   Restart statistics   Order of fields   quit
                                                    Packets               Pings
 Host                                             Loss%   Snt   Last   Avg  Best  Wrst StDev
 1. router.lan                                     0.0%   112    0.7   0.6   0.6   0.9   0.1
 2. lns14.inx.dsl.enta.net                         0.0%   112   30.2  29.0  28.0  36.6   1.2
 3. gi1-4.inx.dist.dsl.enta.net                    0.0%   111   28.1  28.9  28.0  52.8   2.4
 4. te2-2.interxion.dsl.enta.net                   0.9%   111   28.9  31.2  28.2 125.1  12.6
 5. te2-3.interxion.core.enta.net                  0.9%   111   29.1  30.8  27.9 108.6   9.3
 6. te4-2.telehouse-east.core.enta.net             0.9%   111   29.0  31.2  28.4  67.3   7.6
 7. 10gigabitethernet1-1.core1.lon1.he.net         0.9%   111   28.9  31.9  28.1  59.5   4.5
 8. tserv5.lon1.ipv6.he.net                        0.0%   111   29.1  29.4  28.2  64.4   3.4

IPv4 connectivity (Thu 16 Dec 0700 - 1300)

IPv6 tunnel from HE.net (London) to Entanet (Cambridge)

"???" represents 100% packet loss! Not a single packet got through to the destination so no stats can be displayed.

                                                    Packets               Pings
 Host                                             Loss%   Snt   Last   Avg  Best  Wrst StDev
 1. gige-gbge0.tserv5.lon1.ipv6.he.net             0.0%  2014  148.8 148.4 147.2 155.2   0.6
 2. ???

IPv6 tunnel connectivity

Filtering occurs during peak hours Monday to Friday. Never on the weekend.

It's interesting that the time at which filtering ends seems to be adapting. (3pm, then 6pm, 8pm, 6pm. But always exactly on the hour).

Past 6 months (Working Well!)

Firstly, here is IPv6 working pretty solidly over the past 6 months:

IPv6 tunnel connectivity (past 6 months)

Past 3 days (being filtered at peak times)

IPv6 tunnel connectivity (past 3 days)

Past 2 weeks

IPv6 tunnel connectivity (past 2 weeks)

Fri 10 Dec 0400 - 23:59

IPv6 tunnel connectivity (Fri 10 Dec 0400 - 23:59)

Sun 12 Dec 0400 - 23:59

IPv6 tunnel connectivity (past 2 weeks)

Mon 13 Dec 0400 - 23:59

IPv6 tunnel connectivity (past 2 weeks)

Tue 14 Dec 0400 - 23:59

IPv6 tunnel connectivity (past 2 weeks)

Thu 16 Dec 0700 - 1300

IPv6 tunnel connectivity (Thu 16 Dec 0700 - 1300)