View Full Version : Superhub Modem mode - what does it fix ?
Hi,
I've had the Superhub and 50M service for about 8 months now. Before that I was on the 10M service for years. I've found the Superhub a lot less reliable than my old cable Modem, bearable in general.
Recently, however, either the service has become less stable, or I'm noticing the problems more because I'm working from home. I have 2 main problems : the Superhub will drop the WAN connection, or it will reboot itself. I've never had the situation where the Superhub has locked up - I can nearly always access the admin page (although I have to wait for the reboot to finish of course)
I've kept a log over the last month and it has either rebooted or lost the WAN connection about 15-18 times during that period. The connection normally comes back-up within 5-10 minutes, although sometimes it can take longer with the modem waiting for an IP address. However, each occurrence costs me over 30 minutes by the time I've reset the VPN, reconnected and recovered what I was working on. So it's becoming a real pain
I've posted the details up on the support site (here : http://community.virginmedia.com/t5/Up-to-50Mb-broadband/SYNC-Timing-Synchronization-failure/td-p/748729) but it can take a while to get a reply on there.
In the meantime, I've been thinking about trying modem mode, but I was under the impression this was mainly for fixing unreliable wireless issues. I use a wired connection mostly and when I do use wireless, I haven't noticed any drop-outs and the range seems fine. Is it worth me looking at modem mode ? Could it help with reboots and dropped WAN connections ? I don't want to go to the expense of a new router just to find it's the modem or my local cable which is the real issue.
Many thanks,
Pete
I'm in Crawley mate, my SH isn't rebooting, network was playing up a few weeks back but nothing to cause a reboot.
Have you done a scan using inSSIDer (http://www.metageek.net/products/inssider/) installed/run on a wireless capable device/laptop to see what channels each network within reach of you uses then setting your SH to run using a channel not use? The firmware bug has been fixed but its worth a try if you haven't already. Multiple networks using the same channel would cause issues. The SH is in a league of its own so you need to put your arm round it :)
Modem mode is fine, should be anyway. If not then your SH is shot and needs replacing as your power levels seem fine. Note power levels seem to increase when in modem mode, if they jump to high and its unstable then you'll need a tech round to fit an attenuator unless you wish to buy one off ebay.
do you max out on speedtests via a wired connection?
Funnily enough I used a WiFi analyser on an Android tablet this morning. I was looking to see if I could hook up to the neighbour's WiFi because my broadband failed completely just after midnight and the modem could not get an IP address despite numerous restarts.
I noticed that the 2 strongest signals (the superhub and my Cisco VPN) were sharing the same channel, so I manually moved the SH to a different channel (it was set on auto).
Could that have been causing reboots - is that a known issue ?
kwikbreaks
21-12-2011, 18:02
JB66 says the Superhub is still prone to reboots if there is much local WiFi interference (including on R30 which fixed a memory leak in the WiFi driver code which would have lead to hangs, reboots,etc.)
I'm wondering how it handles iffy WAN connections too - maybe the reboots are caused by a bad connection - read the power level sticky and post up your stats.
WRT modem mode that just turns off all the WiFi and routing and the Superhub becomes a cable modem. I've not seen anybody report problems with modem mode (other than inability to set things up).
Here are the levels. From the little I know, the figures generally seem 'OK' ...
Downstream Channels
Lock Status Modulation Channel ID Max Raw Bit Rate Frequency Power SNR Docsis/EuroDocsis locked
Locked QAM256 21 55616000 Kbits/sec 298750000 Hz 5.6 dBmV 40.1 dB Hybrid
Locked QAM256 22 55616000 Kbits/sec 306750000 Hz 6.0 dBmV 39.9 dB Hybrid
Locked QAM256 23 55616000 Kbits/sec 314750000 Hz 5.9 dBmV 39.5 dB Hybrid
Locked QAM256 24 55616000 Kbits/sec 322750000 Hz 5.4 dBmV 39.9 dB Hybrid
Unlocked Unknown 0 0 Ksym/sec 0 Hz 0.0 dBmV 0.0 dB Unknown
Unlocked Unknown 0 0 Ksym/sec 0 Hz 0.0 dBmV 0.0 dB Unknown
Unlocked Unknown 0 0 Ksym/sec 0 Hz 0.0 dBmV 0.0 dB Unknown
Unlocked Unknown 0 0 Ksym/sec 0 Hz 0.0 dBmV 0.0 dB Unknown
Upstream Channels
Lock Status Modulation Channel ID Max Raw Bit Rate Frequency Power
Locked ATDMA 6 20480 Kbits/sec 35800000 Hz 42.0 dBmV
Unlocked Unknown 0 0 Ksym/sec 0 Hz 0.0 dBmV
Unlocked Unknown 0 0 Ksym/sec 0 Hz 0.0 dBmV
Unlocked Unknown 0 0 Ksym/sec 0 Hz 0.0 dBmV
General Maximus
21-12-2011, 22:41
power levels are cool. Despite the numer of people who will jump to the shub's defence and state they don't have any problems with it, simply put, the shub isn't designed for hardcore networking and I think if you tax it too much it just falls over.
Modem mode fixes all the issues because it relieves the shub of it's routing and switching burden and turns it into a modem. This then allows you to use a proper router to do what you need it to do (perhaps a Cisco router to go with your Cisco VPN :) )
I suppose even though I'm using a wired connection, the kids and Mrs are often on laptops / mobiles elsewhere in the house.
After rummaging through the "retired kit" box I've found the Netgear Pro Safe firewall / switch that I used to use with the old cable modem, and an old Belkin Pre-N Wireless Router which can be configured to operate as a Wireless Acces point. So I should be able to put something together to test if Modem Mode improves stability without opening the wallet (always a bonus !)
It's a shame to go back to a 3 box solution - that simplicity was part of the appeal of the Superhub - but small price to pay if it improves the stability and means I can spend less time at my desk.
Ignitionnet
22-12-2011, 11:33
It fixes everything, do it. I haven't looked back since I did.
Quick question. The internet went down early hours of Weds morning. IT was still down 8am on Weds so I called to report the fault. They confirmed no known faults in my area and could see the link was down so booked an engineer visit for Friday morning. Around lunchtime Weds the internet came back online. I did not cancel the engineer, waiting to see if the connection remained up. It has stayed up today although the connection dropped and then recovered again just now (usual problem)
So - should I cancel the engineer as the original fault (no service) has gone ? will the engineer have been canceled automatically (doubtful ?) Or should I leave the appointment in place and ask him to check the line, equipment etc. to see if he can solve these problems I'm having ?
Chrysalis
22-12-2011, 17:31
it doesnt fix anything.
instead it provides a bypass around the problems the router side of the superhub has.
So in effect you could call it a fix as for the end user the problems will no longer exist (assuming new router works good). But it doesnt fix allowing the superhub to be used as a router without the problems.
General Maximus
22-12-2011, 17:51
Quick question. The internet went down early hours of Weds morning. IT was still down 8am on Weds so I called to report the fault. They confirmed no known faults in my area and could see the link was down so booked an engineer visit for Friday morning. Around lunchtime Weds the internet came back online. I did not cancel the engineer, waiting to see if the connection remained up. It has stayed up today although the connection dropped and then recovered again just now (usual problem)
So - should I cancel the engineer as the original fault (no service) has gone ? will the engineer have been canceled automatically (doubtful ?) Or should I leave the appointment in place and ask him to check the line, equipment etc. to see if he can solve these problems I'm having ?
the engineer will still come but if it is up and running he won't do anything. Engineers are only cancelled when they have been booked in advance, a network fault has been reported and fixed and then the engineers are cancelled, which might have happened in this case and we don't know as they could have detected the area fault after you rang up. I had a problem a couple of years ago when my connection was down for 3 days and they insisted it wasn't an area fault. An engineer came round around lunchtime and said that all the calls he has been to that morning had been for the same thing and there was nothing he could do about it. He made a few phone calls and 4 hours later everything was 100% again.
OK thanks - just tried to cancel it on Myvirginmedia.com but it reports that I have no appointments booked - so I guess it must have been canceled already.
morley04
23-12-2011, 14:41
Just received my Super Hub and comparing it to my Old VDMG300 its rubbish my ping's have at least doubled why? and its in modem mode really not happy now :mad:
djfunkdup
23-12-2011, 15:24
Just received my Super Hub and comparing it to my Old VDMG300 its rubbish my ping's have at least doubled why? and its in modem mode really not happy now :mad:
log into the super hub and disable 'ip flood detection'
you will find it in the 'services' menu :)
morley04
23-12-2011, 15:51
Its in Modem mode, Web pages take for ever to load now, pings have gone from 12 to 25 overall not very good at the minute
Chrysalis
23-12-2011, 16:10
yeah as I said earlier it adds latency/jitter. For reasons unconfirmed.
kwikbreaks
23-12-2011, 17:05
log into the super hub and disable 'ip flood detection'
you will find it in the 'services' menu :)That was one of the things VM "fixed" early on in the Superhub saga. As it was fixed quickly I suspect all that was done was to ignore whatever the setting was on in the GUI and handle it as off. Whatever was done it got rid of the embarassing false "dropped packet" reporting from pingtest.net Plus of course in modem mode it will never have any effect even if it can be set.
morley04
28-12-2011, 12:30
A quick phone call and im back to the trusty old VMNG for the time being untill I either upgrade to 100Mb or there is new FW for the hub that fixes the issues.
General Maximus
28-12-2011, 14:22
Good for you dude, it must feel great to be using a proper modem again
Ignitionnet
28-12-2011, 14:27
Good for you dude, it must feel great to be using a proper modem again
Yeah we all feel emotionally moved by the CPE we use to access the Internet.
General Maximus
28-12-2011, 17:20
Yeah we all feel emotionally moved by the CPE we use to access the Internet.
you must be as sad as me then. You have got to be honest though, for something you use, benefit from and enjoy everyday, you have got to feel good when you have got a piece of equipment that kicks ass, especially when you can tell the difference as you have gone from something rubbish to something good.
It is just like car lovers going from a noisey tin can to a brand new Audi or something.
morley04
28-12-2011, 17:27
Well I noticed the difference straight away :) and im now a happy bunny!
General Maximus
28-12-2011, 18:45
so :PP: Ignitionnet
Ignitionnet
28-12-2011, 20:02
you must be as sad as me then. You have got to be honest though, for something you use, benefit from and enjoy everyday, you have got to feel good when you have got a piece of equipment that kicks ass, especially when you can tell the difference as you have gone from something rubbish to something good.
It is just like car lovers going from a noisey tin can to a brand new Audi or something.
No idea, Shub in modem mode seems to work. Couldn't care less what hooks me up to the internets so long as it works which the Shub appears to in modem mode.
In routing mode it's a disaster mind you, and the network around here is still debatable.
--- 194.168.4.100 ping statistics ---
5 packets transmitted, 5 packets received, 0% packet loss
round-trip min/avg/max = 7.2/8.8/10.2 ms
EDIT: Wouldn't surprise if the Superhub for the above poster locked to a different, more utilised upstream than the VMNG. Nothing to do with the hardware and purely coincidence.
Chrysalis
28-12-2011, 20:36
ignition I back up his claims (assuming you reading this)
When I was last able to compare the superhub to the vmng300 I was able to verify the same upstream channel and it wasnt just jitter, the actual base latency also increased which was visible on my tbb graph. In my view it only shows itself if there is sufficent upstream congestion hence people still getting good latency in low utilised areas.
The superhub was fine on sustained downloading, large files etc. But latency sensitive stuff it was visibly laggier and that included web browsing.
My gut guess is that the configuration is tuned to higher queue depths which allows higher speeds in congested areas (hiding congestion) but also adds delays to packets. As in my view the superhub on my connection did give more sustainable speeds under congestion conditions which in theory should make me happier however the latency made almost everything 'feel' slower.
General Maximus
29-12-2011, 08:50
true true. I know a modem is supposed to be a modem but when I ran my speedtests on speedtest.net (with the shub) it always took a few seconds for the page to load, then the testing interface and I always my ping always came back as 35.
When I got my VMNG300 reactivated the first thing I did was head back over to speedtest.net and I knew everything was back to normal straight away; the page loaded pretty much instantaneously and apart from jumping from 21mbits up to 80 something in the test, all my pings were 15ms
Ignitionnet
29-12-2011, 09:47
It should be clarified that 'modem mode' is VM speak for non-NAT, it's no longer doing NAT, firewalling, etc, but it's not a 'modem'.
Instead of the half-bridge you get from router mode where you see your first hop as VM and VM will see your Superhub's WAN side as your final hop it becomes a full bidirectional bridge between LAN and WAN sides of the Superhub.
Looks like in some cases this bridge causes issues. I guess I'm lucky in that it's one of the few things about my VM service that I can't fault since it was put into non-NAT mode for me as a trial in June.
kwikbreaks
29-12-2011, 11:31
So does the way it operates in "non-NAT mode" differ significantly from just putting your router in a DMZ and turning off wireless? If not why did it take all that time to develop?
General Maximus
29-12-2011, 14:29
Well that explains a lot, thanks
Ignitionnet
29-12-2011, 20:33
So does the way it operates in "non-NAT mode" differ significantly from just putting your router in a DMZ and turning off wireless? If not why did it take all that time to develop?
It's been in the original firmware for ages, unsure about VM's *******ised version. It is somewhat different from putting router in DMZ - that still has the Superhub routing traffic and doing NAT, this doesn't it's just bridged straight between LAN and WAN sides of the Superhub's router.
EDIT: I question how much of a swear word the name for a child born out of wedlock is, but that's the word that the filter caught above.
General Maximus
29-12-2011, 21:04
oh dear, you have deliberately sought to flought the forum rules and policy, prepare to incur the wrath of the moderators. Points are on their way........
kwikbreaks
29-12-2011, 22:34
It's been in the original firmware for ages..From what I read it was possible to shut some routing functions off via the telnet interface which they closed PDQ when some idiot advertised its presence on their forum. IIRC in doing that they released a totally untested firmware to the whole Superhub population because some minor radio bugs were fixed at the same time (higher channels only available either the "advanced" or Janet & John interfaces but I forget which).
Surely it couldn't have taken several months to produce the pretty pictures that apparently now show how modem mode works and run a script of already existing commands from the GUI?
Chrysalis
30-12-2011, 03:27
From what I read it was possible to shut some routing functions off via the telnet interface which they closed PDQ when some idiot advertised its presence on their forum. IIRC in doing that they released a totally untested firmware to the whole Superhub population because some minor radio bugs were fixed at the same time (higher channels only available either the "advanced" or Janet & John interfaces but I forget which).
Surely it couldn't have taken several months to produce the pretty pictures that apparently now show how modem mode works and run a script of already existing commands from the GUI?
It did although there was modem mode (GUI version with pretty pictures) in unreleased firmware for at least 2 months prior to R29 beta testing whuch the CEO office was giving out to unhappy customers.
General Maximus
30-12-2011, 08:36
Surely it couldn't have taken several months to produce the pretty pictures that apparently now show how modem mode works and run a script of already existing commands from the GUI?
I don't think it took them that long to physically do it. I don't think they wanted to do it at all because the whole point of the shub is that it was supposed to do everything and solve all their problems regarding end user support and I think they probably spent most of that time trying to fix the routing/wireless issues with the hub hoping that they could turn around and say modem mode was unneccessary and only did it as a last resort at the end
Sephiroth
31-12-2011, 12:04
I think vanity plays a part in VM's behaviour - they made it more shiny than functional. The SH should be functional and good wireless needs two things: Dual band simultaneity and good antennae, neither of which the SH has, nor its vanilla brother.
A poor "unbeatable wireless" device. Modem Mocde at least fixes that - you add a router that does things properly.
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