topic Re: ipv6 sloooow tonight in IPv6 Trial

ipv6 sloooow tonight

chrcoluk — Thu, 27 Mar 2014 04:35:12 GMT

Noticed youtube videos crawling along (youtube is ipv6 enabled).
Did some speedtests and here is results (note I repeated the ipv6 test multiple times to confirm and its 4.30am).
ipv6

ipv4

The huge gap between x6 and normal is bizarre but the single threaded result is bang on to youtube throughput.

Re: ipv6 sloooow tonight

chrcoluk — Wed, 02 Apr 2014 08:03:56 GMT

So I will continue to update even tho noone has shown interest (testers and staff alike).
TBB single threaded tests continue to max out at around 3mbit./sec.
youtube is not consistent its usually 3mbit/sec throughput but sometimes is line speed. So I am thinking now either plusnet are testing traffic management with some routes rate limited, or there is an issue on some ipv6 routes.
Need others to test and staff to respond really.

Re: ipv6 sloooow tonight

brueton — Wed, 02 Apr 2014 08:22:20 GMT

As requested. Both results were carried out using the ipv6test account. I disabled IPv6 in the network properties of the adapter to get the IPv4 result.
IPv6

IPv4

Re: ipv6 sloooow tonight

dave — Wed, 02 Apr 2014 10:18:21 GMT

Could you do us a Wireshark of the v6 traffic? I need to check something with the network guys but I have a feeling I know what it is, the Wireshark will prove it.

Re: ipv6 sloooow tonight

chrcoluk — Wed, 02 Apr 2014 14:07:18 GMT

ok thanks for both replies, will do a wireshark as soon as possible.

Re: ipv6 sloooow tonight

chrcoluk — Wed, 02 Apr 2014 14:31:09 GMT

not very good with wireshark, I tried to apply a ipv6 only filter but still lots of lan stuff in there.
then I cant figure out how to get the result onto here.
any quick howto anywhere?

Re: ipv6 sloooow tonight

AndyH — Wed, 02 Apr 2014 14:41:25 GMT

If you close any background running programs - that will help.
It's fairly easy to filter out traffic on there (put ipv6 and !(tcp.stream eq 0) in the filter bar and you'll see).

Re: ipv6 sloooow tonight

chrcoluk — Wed, 02 Apr 2014 14:45:59 GMT

ok and then how to paste here? I see no way to select.
seems have to do a screenshot instead?

Re: ipv6 sloooow tonight

chrcoluk — Wed, 02 Apr 2014 14:53:38 GMT

trying to attach screenshot but forum hangs forever. bear with me.

Re: ipv6 sloooow tonight

chrcoluk — Wed, 02 Apr 2014 14:54:53 GMT

trying to attach screenshot but forum hangs forever. bear with me.

Re: ipv6 sloooow tonight

chrcoluk — Wed, 02 Apr 2014 15:00:40 GMT

another, I seem to have small tcp window size.

Re: ipv6 sloooow tonight

AndyH — Wed, 02 Apr 2014 15:08:08 GMT

It's a bit strange how your IPv6 speed test doesn't show up on your IPv6 TBB Ping Monitor like it does on your IPv4 TBB Ping Monitor.
Which router are you using by the way?

Re: ipv6 sloooow tonight

chrcoluk — Wed, 02 Apr 2014 15:27:47 GMT

I am using an asus ac66u
ok so I ran the analyser test here.
http://netalyzr.icsi.berkeley.edu/
something of interest from the results.

Quote
IPv6 Tests + –
DNS support for IPv6 (?): OK +
IPv4, IPv6, and your web browser (?): IPv6 connectivity problem +
IPv6 connectivity (?): OK –
Your host was able to contact our IPv6 test server successfully. The requests originated from 2a02:16c8:2000:1400:c911:xxxx:xxxx:xxxx.
It takes 832 ms for your computer to fetch a response from our test server using IPv6, while it takes 196 ms for the same host to fetch a response using IPv4 from the same server.
IPv6 TCP connectivity (?): OK +
IPv6 Path MTU (?): Warning –
Your system can send fragmented traffic, but can not receive fragmented traffic over IPv6.
The path between your network and our system supports an MTU of at least 1496 bytes. The path between our system and your network has an MTU of 1500 bytes. The path between our system and your network does not appear to handle fragmented IPv6 traffic properly.
IPv6 Traceroute (?): OK

The tests do show and affect ipv6 but the affect is more normal, the affect on my ipv4 traffic I dont consider normal, maxing out the line via a speedtest shouldnt cause packetloss and spike latency so high (which it does on my ipv4), I mentioned this on the tbb forums recently, but I dont think anyone else sees anything wrong with it.

Re: ipv6 sloooow tonight

chrcoluk — Wed, 02 Apr 2014 15:37:26 GMT

due to the fragmentation errors and that I know I am using a mtu of 1500 bytes, I adjusted my ipv6 mtu down to 1400 just to be sure that isnt the cause and can confirm a mtu of 1400bytes on my ipv6 does not change the behaviour.

Re: ipv6 sloooow tonight

dave — Wed, 02 Apr 2014 16:17:55 GMT

Wireshark didn't prove what I thought but has given me another idea, chrcoluk I think you may be on to something with the packet fragmentation.
Is anyone seeing a problem on ADSL? If it's just fibre then it could be something to do with the 1492 packet size on PPPoE whereas most people on ADSL with be on 1500 MTU. Need to do some more digging and testing.

Re: ipv6 sloooow tonight

brueton — Wed, 02 Apr 2014 16:34:45 GMT

On ADSL 21CN, not seeing the problem.
Let me know if you want any tests carried out.

Re: ipv6 sloooow tonight

AndyH — Thu, 03 Apr 2014 08:12:51 GMT

@ chrcoluk
Do you have QoS enabled?
Have you tried changing the MTU of the ethernet port (from telnet ifconfig eth0 mtu 1460)?
What about if you download a single file over IPv6 - http://ipv6.download.thinkbroadband.com/1GB.zip what is your speed like then?
What if you put your router's IPv6 address in here http://www.letmecheck.it/mtu-test.php - do you get 1492 as your max MTU?
Edit: Something else - Asus are apparently aware of further IPv6 issues in both their stock and Merlin's builds. I've asked for clarification on what issues. They've given me a couple of development firmware releases to try, but there is something else wrong with my IPv6 which needs to be found and solved first.

Re: ipv6 sloooow tonight

chrcoluk — Thu, 03 Apr 2014 18:52:57 GMT

2nd site gives The maximum MTU size for xxxxx is: 1500
tbb download url is approx 2mbit/sec.
I dont think its my firmware as I have had this firmware installed for about a month now, was working for weeks before this issue started.
the mtu test was done on my router ip as my pc isnt allowing icmp.
my pc mtu for ipv6 is actually down to 1400 bytes mtu to rule out mtu issues.

Quote
C:\Windows\system32>netsh interface ipv6 show subinterfaces
MTU MediaSenseState Bytes In Bytes Out Interface
------ --------------- --------- --------- -------------
4294967295 1 0 17644 Loopback Pseudo-Interface 1
1280 5 0 0 isatap.MerlinASUS
1400 1 2976619 182173 Local Area Connection

Re: ipv6 sloooow tonight

chrcoluk — Thu, 03 Apr 2014 19:10:18 GMT

this loads and says I have no mtu issues.
http://www.ipv6chicken.com/

Re: ipv6 sloooow tonight

chrcoluk — Thu, 03 Apr 2014 20:24:21 GMT

thanks to andy for his time assisting me.
Still no explanation as to the cause of the problem other than to say starting a new login session has brought ipv6 speeds back to normal.