IPv6 support on Virgin media

[dgcarter]

Does anyone know whether (and if so when) Virgin plan to implement IPv6 on its network?

[aleksmariusz]

fair point about the tunnels meant for diff locations.. and as mentioned by others, speed is not going to be anywhere native unfortunately.

[jamesmacwhite]

It isn't the HE side. 6in4 is bottlenecked on Virgin Media, lots of other reports about it from people here and other threads. I've personally tested it on a Linode VPS with a tunnel endpoint terminated there, it can sustain speeds much greater than 20 Mbps. The tunnel may have performance drops at times as there is no SLA or minimum guaranteed speeds with the tunnelbroker service but on Virgiin Media there seems to be a cap at around 15/20 Mbps, no matter what package you are on. 

Interesting you are the Gigabit package, meaning you have Hub 4 and seeing the same performance issues, it rules out this being Super Hub 3 related, given the issues with latency/performance the SH3 has.

[aleksmariusz]

No i don't have the gigabit package on virgin media.. I have a server colocated that has gigabit interconnectivity (i mentioned it to indicate the bottleneck would not be my server, the other end of the speedtest connection)

[jamesmacwhite]

Sorry, I didn't fully read that properly. Yeah 6in4 is unlikely performance to saturate something like gigabit, but it can sustain must faster speeds than the speed test from IPv6 test is showing, but it is accurate, because there is some form of bottleneck or speed cap on 6in4 on the Virgin Media side. Virgin Media deny any throttling but considering the cap is always around 15/20Mbps something in their network is doing something.

[DarkArc]

I don't know if this will be useful but I used to use 6in4 between two virgin media addresses, a server co-located in London and a TunnelBroker account and it was pretty good, I'd just get an overheads based drop.  About 98% of native speed as long as I had my MTU set correct and allowed the ICMPv6 packets needed to adjust the other ends MTU.  This was 2003 to 2010 (ish) according to my TunnelBroker account.

A key thing was if you blocked ICMPv6 on the tunnel, it would run really slowly as it would fragment the packets all the time.  A VM to VM connection lets you try it without anything but the core network involved, you can avoid the peering point then.

Unfortunately a few years ago though my 6in4 just stopped working properly - I don't remember if it got really slow or had stopped working entirely and protocol 41 packets weren't reaching the other end - but I switched to L2TP (some tunnels with ipsec and some without) and that ran full speed.

I gave up on my HE Tunnel as I had IP's from other providers, but it was good service until then and much faster than 15/20Mbps (think I got 130Mbps peak down but I can't really remember what the connection speed I had from Virgin was at the end) - my point is that the overhead is negligible, and this was on much older router hardware than most people will have now.

[aleksmariusz]

I've an existing openvpn tunnel to my colo provider, i'll see if i can funnel my 6in4 traffic using a static route via that openvpn tunnel instead to test the suggestion that VM is throttling protocol 41 (since that traffic path would result in 6in4 being encapsulated inside the openvpn payload which is simply udp 1194)..

should be a pretty good test if there's something funky going on VM's side

[jamesmacwhite]

That was something I was going to test at some point from my Linode VPS. If you pass something like a /64 from your routed /48 over a OpenVPN tunnel from another server outside of VM, I'd be interested to know what the performance is like when the tunnel doesn't terminate on a Virgin Media IPv4. I suspect you may find the performance drastically better, but would be good to confirm it. Keep us informed.

[jamesmacwhite]

Good info DarkArc, as far as I know I'm conforming to the spec regarding ICMPv6 not being blocked. OpenWrt provides default IPv6 related firewall rules which should be compliant out of the box in more recent versions, but I'll double check. The metric value on my 6in4-wan6 interface on my OpenWrt router is 1480, which matches the value specified on the tunnel side. OpenWrt does default to 1280 when configuring a 6in4 interface for the first time, which is low and can offer even worse performance, but even correctly set at 1480 it doesn't resolve the speed issues we are all seeing, hard limit between 15/20 Mbps, seems constant.

My theory has always been if you had HE 6in4 coming across a VPN tunnel where the tunnel itself does not terminate on a Virgin Media residential connection, I think you'll find the performance much better and probably more in line with IPv4, if that's the case even with the encryption overhead, kind of says it all really, but need to confirm it.

The irony for me is I have two WANs, Virgin Media and a backup 4G EE connection in failover, because EE 4G has IPv6, I have the IPv6 prefix (only a /64 sadly) NDP relayed across to my LAN so all clients have both 6in4 and EE IPv6. The IPv6 performance on EE is so much better and the upload speed overall is ironically better than my VM connection of 10 mbps, compared to the average 30 mbps from EE. Of course EE IPv6 is native, but even 4G beats the 6in4 performance when on Virgin Media.

[ksim]

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@jamesmacwhite wrote:

That was something I was going to test at some point from my Linode VPS. If you pass something like a /64 from your routed /48 over a OpenVPN tunnel from another server outside of VM, I'd be interested to know what the performance is like when the tunnel doesn't terminate on a Virgin Media IPv4. I suspect you may find the performance drastically better, but would be good to confirm it. Keep us informed.

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What is the purpose? Why even spend time on this? IPv6 traffic or 6in4 traffic (server in London) wrapped into a VPN tunnel (wireguard in my case) is working fine, I can max out VM connection. BT/Sky/TalkTalk - maxing out connection using plain HE tunnel (HG612 bridged to the same router, the same laptop, even the same network cable, VM loves to question my ability to make cat6 cables). VM - throttling.

It just someone at some point in the time in VM configured flood protection and tried to limit unknown to the person protocols. And as we discussed the level of incompetence in VM doesn't allow them to understand, investigate, and fix the issue.

[aleksmariusz]

... so when I bypassed terminating the same hurricane electric tunnelbroker setup/endpoint within virgin media's network using a FOU tunnel which encapsulates ipv4 inside UDP at my gigabit-connected colocated server one hop away from HE's ipv6 backbone), the results are a LOT different:

basically same hub3 router, same linux kvm guest acting as my gateway/tunnel-endpoint termination, except the traffic is encapsulated WITHIN udp so Virgin Media' network mangling is not detecting it as protocol-41 traffic.. (vs the 20mbps i was seeing going direct).

So basically.. Virgin Media network engineers, you've got some explaining to do..