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UDP issues on SuperHub3 - collective thread

dinth
Dialled in

Hi. I decided to open a collective thread for UDP issues on SuperHub3, as it seems that many users are pestered by them, the impact is high and Virgin Media is not aware or fails to acknowledge the issue so far (they've been trying to fix my issues for a past year and nobody ever suggested that this has anything to do with UDP packets, until i found whats exactly the issue on my own).

This is the main thread for those issues was this one: https://community.virginmedia.com/t5/Speed/My-350Mb-connection-is-throttled-to-10Mb/td-p/3953746/pag... but it was originally created over a year ago and has a slightly misleading title. 

What we know so far:

1. The issue only occurs on SuperHub3 (and reportedly on SuperHub4) modem. SuperHub2 users are not affected. 

2. The issue occurs if an app/service is using an UDP connection to the internet. Examples of such apps: BBC Iplayer app, most online games, Microsoft Teams, Skype, third party VoIP apps, all kinds of VPN apps, torrent download apps. 

3. All UDP connections are performing very badly on Superhub3 modem, but also whenever there's a significant UDP traffic passing through the modem, other, non-UDP internet connections are slowed down to crawling speeds.

4. Depending on an user, the reported slowdowns are to between 10Mbps and 2kbps (!) speed measured through Speedtest. At the same time ping times go up all the way to 2000+ ms and huge packet losses (sometimes over 40%) occur. In other words, even web browsing is not possible if there's a significant UDP traffic going on through modem. 

5. VM street level fixes do not fix the problem - i had a whole uplink cable between CATV manhole and Virgin Media cabinet replaced by VM and it has not fixed the issue.

6. Replacing a modem does not fix the problem either - replacement SuperHub3 modems also have same issue.

7. Here's how the issue looks like on ThinkBroadband/Speedtest with just 1Mbps of UDP traffic flowing through the modem:

Screenshot 2020-08-25 at 19.17.25.png

It's really sad, that Virgin Media fails to acknowledge this problem, as hundreds, if not thousands of people may be severly affected by it. The advice VM is giving out to the users is unhelpful and sometimes harmful (I've been told i need to chase the walls in the newly refurbrished house to replace my VM cable and desperate to fix the problem I have done that). Just look how many threads are being open on this forum describing similar issues with apps using UDP connections. 

 

192 REPLIES 192

One application is for voice service. The modem needs to be able to recognise the traffic, so it can be put in the correct service flow (prioritised).

Rod-IT
On our wavelength

But again, why would this still be handled by the router in modem only mode, surely the only people who deliberately put their router in to modem only mode, are capable of figuring the rest out or will be replacing the router part with something also capable of doing just that. Even if they we're not, VM have the get out card here by saying, when the router is in modem only mode we offer no technical support, if you face any issues, we recommend you put it back in router mode.

Either way, even if these priority queues are still happening, it's not doing a good job of it, i am often disconnected or interrupted on calls over Skype, Teams and Zoom.

As a side note, i am not arguing or trying to be picky, simply trying to understand what is happening in the background, so what you have replied with is helpful to know.

In this context, voice service is regular phone service. Skype, Zoom etc. go to the service flow that carry regular internet traffic.

Rod-IT
On our wavelength
Makes even less sense than - the phone ports on the back of the SH3 as far as i know are disabled and have never been used, but why would the modem even see this traffic.

For completeness, I do have a telephone package, but it's never used incoming our outgoing.

Thanks for your info though

The modem would see it because of how the path between the modem and the CMTS has been engineered. That is the short answer. 🙂

Rod-IT
On our wavelength

I assume that only applies if and when a call comes in, which in my case is hardly ever, if ever.

 

Yes, that particularly service flow only carries traffic when you make/get a phone call, but the modem is still inspecting the traffic. To add more to the picture: ACK suppression is another feature found in a DOCSIS modem. When enabled, all ACKs belonging to the same TCP stream between upstream bursts will be merged.

So is it conceivable that the modem somehow begins acting weird when there are UDP flows? Sure.

I have just had an engineer and a network engineer out and demonstrated the UDP problem with a torrent.

The network engineer admitted that it is the router and that it is deliberate. He said it is to do with f-secure on the router. After telling me my ubuntu torrent was illegal (HA!) he said torrents use all the frequencies available on the fibre line, whereas youtube might only use 3 or 4 frequencies and the others would be free for any other connections.

Essentially virgin have deliberately blocked superhub3 from using torrents for security.

I am not a technical preson, but is there a way to configure a bit torrent client to use less of the frequencies like youtube would?

Has anyone else got any updates or have any workarounds?

Don't use the UDP protocol ,use TCP,that's the only way you will get the speed.

 

 

 

fordy
On our wavelength

> Essentially virgin have deliberately blocked superhub3 from using torrents for security.

Sorry this is not true, and not all torrents are illegal.

I have worked with VM on this, there is 100% a fault with the superhub 3 and superhub 4.  A superhub 2 resolves it.