Kitz Forum
Broadband Related => ISPs => Topic started by: Bowdon on March 21, 2020, 10:48:02 AM
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I've noticed that VM are covering a few cities now with their 1Gig service, on the docsis 3.1 network.
So far I've not seen anyone post any experiences with it. It could be a game changer for not only VM but also the fast broadband we all want.
I wonder if there are any stats on its uptake. Usually when a new service comes out at least someone on the forums try it and post their experience. But so far I've not seen anyone posting anything about it.
If anyone on here signs up, let us know what its like. It would be interesting to hear the feedback on it.
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plenty of feedback on the virgin forum about 1gig service.
one should remember the hub they supply only has gigabit ports, so once you factor in the actual real-life achievable speed form a gigabit port you'll end up with around 940Mbps being supplied by the hub (even though the actual speed being supplied to the hub is usually about 1.2Gbps).
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Uptake is tiny as you'd expect.
It's not a game changer. Most people have no interest in gigabit and certainly aren't prepared to pay £62 a month for it.
The bulk of VM customers are still on 100 Mbit. Many of those on higher tiers are on them because they came with the TV.
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well it's only tiny because the areas covered were relatively tiny.
most of the complaints came from people who simply didn't understand the technology involved.
1Gbps package, IMO, is not about supply all 1Gbps to one device, it's about having enough to spread over mulitple devices without seeing any impact.
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I think could be a game changer in the future. But you're right £62 is a lot of money, and also tying it to having the phone and tv package will also slow it down.
I think whenever a new speed comes on the market its always the more tech minded people who go for it first.
I'll have to keep my eyes on the virgin forum. I noticed last week someone mentioned my area was on a list to be upgraded to 1Gig. So I thought I'd see what the experience is like.
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well it's only tiny because the areas covered were relatively tiny.
Uptake is the people taking the product versus those it's available to. Obviously in areas where it's not available the uptake is zero.
Uptake of 500 is also minimal. Uptake of 350 isn't very high either: single digits %.
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I'll have to keep my eyes on the virgin forum. I noticed last week someone mentioned my area was on a list to be upgraded to 1Gig. So I thought I'd see what the experience is like.
There is no list of areas being done. They have been announcing area by area when doing the upgrades.
Manchester has already been done.
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I have a friend who works for Virgin as a field engineer and he says the roll out of 1gig is going smooth and they're on target (whatever that target is). My plan is when I eventually move place and the place I move into has Virgin (which it does) when my contract is up with Zen i'll move to Virgin and by that time I suspect my area will have 1gig.
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Thread bump.
Do more people have Gig1 now/have experience with it, now that its available nationwide(?), to those who can get Virgin?
Does DOCSIS 3.1 have better latency than DOCSIS 3?
See that there is a deal on Gig1 (+Phone+O2 Sim) for £55/month.
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Does DOCSIS 3.1 have better latency than DOCSIS 3?
It does not. VM are still using 3.0 upstream so no real difference.
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It does not. VM are still using 3.0 upstream so no real difference.
Thanks. When I briefly tried M200 back in October, the speeds seemed ok but the latency was poor. I know DOCSIS has more jitter but it seemed very spikey. I’m not sure whether it was down to congestion or not (which the local area did suffer from previously). Was hoping Gig1 might be better with having a higher minimum speed guarantee.
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On the VM forum I read a fair few reports from people who had no issues on the tier below it, but than after upgrade it was slower than the lower tier, and they were blaming technical issues with the new docsis 3.1 channel, VM only add a single channel which seems a bit tight of them and only on the downstream so seem to be provisioning it with the absolutely minimal possible infrastructure. Those issues I dont think were congestion related though as the people appeared to be in areas that didnt have capacity faults.
The package seems hideously balanced, only 50mbit upload so 20:1 ratio. I remember when ignition started a blog on the ratio many years ago and VM eventually got to 3:1 ratio I think with their 30/10 package?
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The one channel is fine. I believe the issues are largely with the wonderful software on the Hub 4. Only times there are technical issues with the 3.1 channel the network is a noisy shonkfest that can't be properly maintained due to UK law and poor disconnection policies.
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Considering it now that cityfibre have kerbed their rollout and cancelled my street.
But of course this guy gets told there is no congestion and then posts this tbb graph.
https://www.thinkbroadband.com/broadband/monitoring/quality/share/02f86fc728c8dee4e6013d312cedf06a447596a1-07-04-2022
So the issue for me, I get the speed uplift, but do I want to risk my streaming experience, 100s of mbit nice at 4am, but not so much if I cannot watch netflix at 8pm.
However I do see that there is a cooling off period, so a trial period might be worth a shot.
Is it true that there is only 108mbps of upstream bandwidth shared across everyone on the UBR? A giga1 user would saturate maybe 20% of that just from downloading. Thinking it would be like adsl would have to agressively shape the upstream to not affect the downstream due to the aggressive asymmetric nature.
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It's not true it's 108 Mbit between everyone on the CMTS, no.
A high tier user won't consume 20% of it downloading as cable has mechanisms to suppress and accumulate acknowledgements.
Localised congestion is still a thing and might be for a little while but should all be sorted in time through 3.1 upstream and Project Mustang.
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plenty of feedback on the virgin forum about 1gig service.
one should remember the hub they supply only has gigabit ports, so once you factor in the actual real-life achievable speed form a gigabit port you'll end up with around 940Mbps being supplied by the hub (even though the actual speed being supplied to the hub is usually about 1.2Gbps).
If you know what you are doing, it's possible to get more than 940Mbps out of the hub 4:
https://tech.msh100.uk/virgin/networking/2020/10/17/virgin-media-greater-than-gbit/
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It's not true it's 108 Mbit between everyone on the CMTS, no.
A high tier user won't consume 20% of it downloading as cable has mechanisms to suppress and accumulate acknowledgements.
Localised congestion is still a thing and might be for a little while but should all be sorted in time through 3.1 upstream and Project Mustang.
Hmm thats good and bad, not sure I want my acks to be manipulated by the isp. How much shared upstream is there if you dont mind answering? For some reason I cant find this info, I remember a decade ago this stuff was much easier to find.
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If you know what you are doing, it's possible to get more than 940Mbps out of the hub 4:
https://tech.msh100.uk/virgin/networking/2020/10/17/virgin-media-greater-than-gbit/
Seems a silly configuration, they even admitted as much in the comments. Why waste the the second switch when two ports will do the job just fine leaving the other switch able to be used.
Fair enough if they want to do it with four, but when sharing the idea publicly its unhelpful to overcomplicate things.
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Hmm thats good and bad, not sure I want my acks to be manipulated by the isp. How much shared upstream is there if you dont mind answering? For some reason I cant find this info, I remember a decade ago this stuff was much easier to find.
Each CMTS has multiple 10G uplinks. Each cable segment has 4-6 x 27 Mbit/s upstream channels. A single Gig1 user has half the capacity their modem is addressing. VM have major problems with network noise due to regulation preventing them taking stronger measures to remove it.
The acknowledgement suppression has been a thing for 20-odd years. It doesn't break anything.
EDIT: It's also not done by the ISP, cable modems do it. Rather than sending every acknowledgement separately if they have acknowledgements arrive while waiting for upstream slots they'll acknowledge everything cumulatively. Saves upstream capacity all around.
Also on the matter of the guide I'm going to cut the guy all the slack in the world given he gave us https://bidb.uk/
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Ok so the acks are delayed for a few ms so they just jittered, so still same bandwidth cost just better allocation of timeslots. Your wording made it sound worse. The shared upstream segment is between 108 and 162mbps. Thanks.
A guy who claims to work for VM has told me there is no giga1 customers for every cabinet on my street meaning I would be the only one on the docsis 3.1 DS channel, and the average speed for the one 500mbps customer is basically full throughput both directions. Although I gave him my postcode he then wanted my full details which I have refrained from as there is no way of knowing if he is legit.
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They aren't jittered, it cumulatively acknowledges each TCP stream at each slot rather than buffering them and sending them all. Cable modems have a bunch of functionality above layer 1 and 2.
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Also on the matter of the guide I'm going to cut the guy all the slack in the world given he gave us https://bidb.uk/
Fair point, and I can see how he might not have wanted to document a slightly different method he didn't test himself, even if he "thinks" it should work fine. I do forget sometimes that not everyone has a lot of free time for this stuff.
Now if he could just fix that site so the coverage dots work when zoomed in. He DOES seem to have finally fixed the weird scaling glitch I was having which the key would keep jumping between two different sizes.
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They aren't jittered, it cumulatively acknowledges each TCP stream at each slot rather than buffering them and sending them all. Cable modems have a bunch of functionality above layer 1 and 2.
Jitter was perhaps the wrong word to use, but cumulatively adding is still sending them all, so I am misunderstanding you and will leave it here.
Depending on what cityfibre come back with, I will order VM, they have a cooling off period, so I can analyse actual ACK traffic levels to answer my own question then, and see if it works ok during peak for what I want it for.
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You won't see anything on the cable modem side. Your router will send as normal. You can of course capture on a remote server if that turns you on.
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Yep I was going to check server side if ACK's were been modified to remove data to make them smaller or just batched together.
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Okay I'm not sure if I'm being clear.
Cumulative acknowledgement (http://www.cs.newpaltz.edu/~easwaran/CCN/Week6/tcpACK.pdf) is a specific technical term and I was using it that way. It means to send a single acknowledgement to acknowledge all of a stream received so far.
Cable modems behave as layer 4 proxies and send a single acknowledgement covering all the acknowledgements they have received for a particular stream.
You will see far fewer acknowledgements at the server-side than your client machine is transmitting. This neither breaks or degrades anything as loss is handled by selective acknowledgement (https://en.wikipedia.org/wiki/Retransmission_(data_networks)).
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Ok does anything break if selective acknowledgements are disabled? You are right that after you gave me the technical term I understand what you was saying better.
Thank you for providing it as it is interesting to learn something new.
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That's very useful as I've seen instructions for tweaking NACK and SACK but never understood what they were.
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Ok does anything break if selective acknowledgements are disabled?
Not that I'm aware of, Sir.
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Not sure why you'd want to.
TCP Selective Acknowledgment (SACK) is used to improve performance of data transfer on TCP stack.
Disabling TCP SACK will negatively effect the data transfer performance. The magnitude of performance hit depends on type of data transfer.
Its basically mitigating the delay of waiting for an upload time slot by reducing how many ACKs need to be sent when that time slot becomes available.
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I dont turn them off, just a question out of curiosity