50M : Upstream congestion - business service

[ccarmock]

I have had excellent performance on the 50 Mb/s business cable service with fixed IP subnet.

Speed tests usually run at around 48 Mb/s with very low jitter - 1-4 ms usually.

Last Friday there was a problem that caused the business Superhub to go offline - diagnosed as noise in the area , which cleared spontaneously within 30 mins.

Prior to this problem my upstream was locked onto Channel 2. Since the superhub reset on Friday it has gone to Channel 5 and performance is poor- around 6 Mb/s right now downstream.

I have just spoken to business faults. The engineer checked the port I am on - NMAL Cable 8/0/1 apparently. He said it was showing sustained 100% utilisation and has now logged it with the network team.

I asked if he could push me back onto Channel 2, but he said no he couldn't.

However I thought the idea was that if more than one upstream was available in an area then the Superhub would select the one with the lightest utilisation when it booted up? I have tried resetiing it multiple times but always it comes up on Ch 5 the congested one.

I might have misunderstood how this works though.... can anyone advise?
Perhaps it locks to the one with the lowest number of other users -which may not be the lightest loaded one of course.

[babis3g]

They don't provide a tool (they should really because i know for this reason are many complain at VM forums) where we can change the channels to less congested

Had this issue my self many times because almost central London the network is almost congested all the times
With older firmwares it was easy after 1-3 resets will change channel
After R36 firmware (i don't have the business SH but i think is the same for all) it will not change channels easy

I manage to force the SH to change channel after about 30-40 resets ...so keep trying if you have enough time and good luck

Is something simple and they don't give us a tool or option in the SH to sort it by our selfs

[qasdfdsaq]

Originally Posted by ccarmock

I thought the idea was that if more than one upstream was available in an area then the Superhub would select the one with the lightest utilisation when it booted up?

I might have misunderstood how this works though.... can anyone advise?

Unfortunately the Superhub doesn't get to do any selecting, there's some brief communication from the network side which instructs it which channel(s) to use.

The network chooses which channel to assign client modems to based on some magic secret sauce algorithm that we know little to nothing about.

[ccarmock]

They have moved me to a different upstream today - which I see reflected in a different Channel number- moved to 2 from 5. Performance seems better now...

[babis3g]

Thanks for update...is nice to know they can do it after requested

[horseman]

Originally Posted by qasdfdsaq

….The network chooses which channel to assign client modems to based on some magic secret sauce algorithm that we know little to nothing about.

Sssh…..some know but don't tell anybody else:
Cisco Magic Spell Book

[qasdfdsaq]

Sssh! VM don't use Cisco equipment everywhere

[ccarmock]

Well some updates on my upstream congestion problem. Having had to escalate to a customer complaints manager for help here I have now been told that my problem is indeed upstream congestion, that designs are underway to increase capacity on the New Malden node. However due to space restrictions they have to carry out building work in order to accommodate more racks of equipment. Estimate date is mid November worse case.

I do remember someone saying that the New Malden node is actually in one of their office buildings so maybe it's just moving internal walls to expand an equipment room as opposed to extending the building itself!

The strange thing is - on the 50/5 business service, I have just done a speed test - getting around 12 MB/s down and 5.3 Mb/s up.

Doesn't sound like upstream congestion to me? However when talking to them about performance they always look at upstream never downstream. Any ideas why?

I still have just 4 downstreams. Given that business services only go up to 50 Mb/s down will there ever be more than 4 downstreams for the business service? Or do all users get more when they are available in the area?

[babis3g]

The experts should answer to you soon but the little i know it can be upstream congestion because VM confirmed at their forums in the past for similar problem i had

Upstream use QAM 16 and is only in use one channel at the moment so seems most of the cases is due to upstream

Look my graph how UPSTREAM congestion changed after reset SH and changed upstream channel from 358000 mhz to 45.000 mhz


Downstream channels and hoping upstream sometime later when will add more will be for everyone

EDIT
Of course if your area has too many users can cause and over subscribe congestion as well due to heavy downloads

[ccarmock]

I understand what you are saying, but since I am getting the maximum of just over 5 Mb/s upstream but only 12 Mb/s downstream (on a 50 Mb/s service) how can this be upstream congestionwhen I get full throughput on uploads.

[babis3g]

It can be...when i find out after around 4-5 pm(long time ago that upstream congestion) my speed that time from 100mb, tested was down to 50-60mb

[ccarmock]

Yes I understand why upstream congestion can cause downstream performance issues. but since I am getting the full 5 Mb/s upstream it doesn't seem congested....

[Sephiroth]

What you didn't tell us is whether or not your downstream channels changed as well. When the upstream goes from 1 or 2 to 5, it means they've turned on the upgraded upstream. So if the "upgraded" downstream is no as well, you've ended up on a congested set of downstream channels. In other words, a careless (that's being kind) resegmenation.

Does that fit?

[babis3g]

Originally Posted by Sephiroth

What you didn't tell us is whether or not your downstream channels changed as well. When the upstream goes from 1 or 2 to 5, it means they've turned on the upgraded upstream. So if the "upgraded" downstream is no as well, you've ended up on a congested set of downstream channels. In other words, a careless (that's being kind) resegmenation.

Does that fit?

Hi Sephiroth
If you mean for me .... then downstream channels stayed same locked at 29900 mhz (out of 5) and are still same up to date
Only upstream changed and you see the graph how congestion change

The only Upsteam channels since march (i am with VM) are...ch id 5>35800 and ch id 4>45800 mhz (at least these are the only appearing to me and the SH can log into them) and are the same when i was with XL 30mb(when first joined)...now i am with 100mb are still same upstream channels, always them 2 till now
Don't look to me there is any upgrade to Upsteam yet (only downstream from 4 to 5 channels)

[ccarmock]

for me just the upstream changed. the 4 downstream channels have never changed....
I understood there to be 4 upstreams too for this area and they just moved me to a different one, but the downstreams stayed the same.