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Virgin Media UK Move to Fix 20Mbps Speed Cap on IPv6 Tunnels

Thursday, Aug 6th, 2020 (8:05 am) - Score 25,585
virgin media superhub 3 router

Broadband ISP Virgin Media is finally moving to develop a fix for a long-running, albeit quite technically niche problem, which severely throttles IPv4 internet traffic – often reducing download speeds to under 20Mbps – when the data packets carry Protocol 41 (i.e. the IPv6 encapsulation / tunnel protocol).

Granted, that’s not the catchiest of news titles, but then this does represent quite a niche bug. ISPreview first became aware of this problem a year ago, but at the time it was only being reported by a tiny number of people, although Virgin Media’s long-running struggle to properly implement IPv6 internet addresses has meant that a growing number of users are starting to run into the same issue.

At present customers are only assigned an IPv4 address, although naturally some of the provider’s more technically minded customers still want to be able to use the latest IPv6 standard. One way of achieving that is by harnessing a 6in4 tunnel service via Protocol 41 (IPv6 encapsulation), which works with a third-party service (e.g. Tunnel Broker) to embed IPv6 packets inside IPv4 packets.

On most UK broadband providers this works fine and has little to no discernible impact on your connection speed, unless you happen to be a Virgin Media customer with one of their HUB 3.0 (SuperHub v3), Hitron or older routers. As one customer, Chris, told us: “Specifically, 6in4 tunnels that originate from a VM IPv4 address are limited to ~20 Mbit/s downstream throughput, even though the VM connection is easily capable of far more (500 Mbit/s in my case).”

Virgin Media did initially probe this problem last summer (here), but oddly the operator concluded that such connections were running correctly “and they can see no issues with speed/reliability … we do not traffic manage / traffic shape our broadband connections, however VPN and other forms of tunnel connection are not supported and we cannot guarantee a perfect connection between points.”

Naturally that didn’t go down particularly well, not least since the issue is clearly not due to the endpoint equipment nor the tunnel itself but something on the VM network. Meanwhile an increasing number of customers have become tired of waiting for IPv6 and thus more of them are now starting to run into the same problem (here and here). The issue also seems to be present on both their business and residential service.

We began raising this problem with the operator last week and, after a bit of nudging, it appears as if they may finally be prepared to resolve it.

A Virgin Media Spokesperson told ISPreview.co.uk:

“We’re currently investigating this issue further which affects those customers who choose to use 6in4 IPv6 tunnels. This may require a firmware update from the vendor to fix the problem.”

At present it’s unclear when such a firmware update might be released (bug fixes from VM have a tendency to take a long time..) and whether or not they’ll be doing that for all of their affected routers, or only some of them. On this point we note that customers who have recently upgraded to their top 1Gbps (DOCSIS 3.1) package with the latest HUB 4.0 router do not appear to suffer the same issue.

We also asked for an update on Virgin Media’s much delayed IPv6 roll-out plan, although the response we got back merely echoed what they said last year: “We’re currently in the process of finalising our plans for IPv6 deployment and will provide an update at the appropriate time.” We wonder which will come first, VM’s IPv6 roll-out or a fix for the 6in4 tunnels bug.

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By Mark Jackson
Mark is a professional technology writer, IT consultant and computer engineer from Dorset (England), he also founded ISPreview in 1999 and enjoys analysing the latest telecoms and broadband developments. Find me on X (Twitter), Mastodon, Facebook and .
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23 Responses
  1. Avatar photo Aleksandr Metslov says:

    I’ll by cynical:
    VM service… What else can you expect from them?

    1. Avatar photo Buggerlugz says:

      Yes, I agree. Also spat my coffee out at “we do not traffic manage / traffic shape our broadband connections”. I pondered if that VM spokesperson may just have a very long nose.

    2. Avatar photo CarlT says:

      If you can prove traffic shaping / management Ofcom would be very interested.

  2. Avatar photo David J. Fiddes says:

    Thanks for highlighting this issue. Hopefully it will be fixed soon. I’ve been one of the affected users and running an IPv6 tunnel since 2009. It would be good to be able to use it again.

  3. Avatar photo Chris Sayers says:

    Quite frankly its downright lazeynes from Virgin Media, we hate being regulated, on occasions regulation is useful and needed, quite why VM is stalling on impimating IP v6 is beyond me, @Mark Jackson, any update from last years report, https://www.ispreview.co.uk/index.php/2019/10/update-on-ipv6-plans-for-virgin-media-talktalk-and-vodafone.html

    1. Mark-Jackson Mark Jackson says:

      The quote that we got this week (above) is basically identical to that one.

  4. Avatar photo James White says:

    Glad this has been picked up! This has long been an issue and everyone who’s tried has struggled to get any traction with VM on this. Hope it helps resolve this issue finally!

  5. Avatar photo paul c says:

    “…however VPN and other forms of tunnel connection are not supported and we cannot guarantee a perfect connection between points.”

    Given so many of us are working from home and many if not most companies use vpn to access corporate networks from home, it would be good to see Virgin take a more positive stance to support their users rather than just say meh, not our problem…

    1. Avatar photo James White says:

      I think that’s their default stance of covering speed problems/complaints when something else other than just Virgin Media’s network is in the path. Granted that was the canned statement response last summer, a lot has changed in the world since then, but ironically, the issue wasn’t VPN performance overall. I regularly use a VPN and the speed is fine on Virgin Media from an IPv4 only point of view, the issue is specific to 6in4/protocol 41. Right now if I tunnel IPv6 over UDP with Wireguard, there is no issue, the specific protocol 41 traffic seems to be affected by something.

      At least now it seems Virgin Media are at least looking into it. It’s still unclear what the issue is, whether it be their network or a CPE issue. If a firmware update is needed, it points to it being the CPE.

    2. Avatar photo CarlT says:

      Pay for the business service if that’s a concern.

    3. Avatar photo Ian Tommins says:

      @CarlT The business service has the same problem, and same lack of support (because the first line engineers don’t understand the question and it’s not escalated to someone who does).

  6. Avatar photo Barry Hoy says:

    This company is a nighmare should be reported the customer service is a joke.

  7. Avatar photo Johanna Elvidge says:

    I pay for 100mbs with VM, my download speed is around 20mbs. Today I called them and they tried to upgrade us to a new hub and service, which looking at the article above may have fixed the issue – however VM wanted to increase our monthly payments in order to get this, now I may be being cynical, but offering a paid for’upgrade’ as a way of fixing a problem which they are aware of absolutely stinks.

    1. Avatar photo Qq says:

      You’re willingly upgrading, fault replacements are free presuming the technical side have said that it needs to be done, if you’re just wanting to upgrade for the sake of upgrading then yes, you’d be charged.

    2. Avatar photo Johanna says:

      I do not want an upgrade,I did not call to upgrade, I called to report the fault. I want the service which I pay for to operate as it should. Offering to fix the fault by my paying for an upgrade is not what I was expecting, nor what I am doing.

    3. Avatar photo Qq says:

      Speak to faults & not customer care then. Faults don’t have tools to upgrade, so if they’re trying to sell; you got the wrong department.

  8. Avatar photo LV says:

    It could be worse, you could be using an email address from them, so insecure it takes only a couple of minutes to hack into them, 8 to 10 characters and no special characters. You don’t stand a chance.

  9. Avatar photo Lewis Watkins says:

    Virgin media are terrible, agree to price on the phone then up the price all the time.. Personally I’ve also had better Internet with sky and better prices.

    1. Avatar photo CarlT says:

      Thankfully you can I guess take Sky and enjoy their superior service and better prices.

  10. Avatar photo PerplexedTheta says:

    The lack of an IPv6 address was the primary reason we left Virgin Media for BT in July. Had to make some changes to the stock setup (namely, wiring some Cat5e for the VDSL line) but we’ve had a great time since!

  11. Avatar photo Hunter says:

    I don’t want ipv6 anyway lol

    1. Avatar photo Dariusz says:

      That doesn’t mean other people don’t need.

  12. Avatar photo Bob Geddes says:

    Since Virgin announced their 1Gig service is now available in London my IPv6 via HE no longer has the 20Mb cap (using SH3). Am I alone?

Comments are closed

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