Superhub bouncing
 

At least once a day, my Superhub will drop connection and I can't see why. The power levels are slightly higher than expected (+9dB) but shouldn't be causing much trouble really. SNR levels are good (+44dB). The event log shows:

https://www.cableforum.co.uk/images/...2011/02/16.png

And here are the levels:
https://www.cableforum.co.uk/images/...2011/02/17.png

Any ideas?

---------- Post added at 00:22 ---------- Previous post was at 00:19 ----------

Just as I hit Submit there, it dropped again.

Re: Superhub bouncing
 

Sorry, I'm no help, but I had to say your subject line made me smile. With the frustration that some people are having I pictured it 'bouncing all the way down the drive after being flung out the window LOL

I'm sure someone will be along soon who may have something more constructive to say.

Have you turned off the firewall and ip flood?

Re: Superhub bouncing
 

6db attenuator would sort that out. call up and book a techie

Re: Superhub bouncing
 

If this is the case then that's really annoying. The engineer took my attenuator away when he came to install the 50meg. He connected the coax to his piece of kit and said the signal was "perfect" and chucked the attenuator in his holdall. :td:

Re: Superhub bouncing
 

probably needed one to take home lol

Re: Superhub bouncing
 

Called today and an engineer is booked for tomorrow morning. Turns out the superhub has adjusted itself 267 times in the last 3 days.

Re: Superhub bouncing
 

That's nothing. W-CDMA phones adjust themselves 1500 times a second.

Re: Superhub bouncing
 

It won't necessarily sort the issue that the OP has.

Re: Superhub bouncing
 

A 6db attenuator will not sort it out, expect a modem swap and the same issues on the new hub

Re: Superhub bouncing
 

Why same issues on the super hub?

---------- Post added at 20:19 ---------- Previous post was at 20:17 ----------

Some info on said T3 error's, and how the modem works:

http://bradyvolpe.com/docsis-101/doc...n-maintenance/

Re: Superhub bouncing
 

Because techs have no tools to detect what is causing t3 timeouts or why it occurs, they also can't pass it to networks as the tech can't prove it's a network issue

Re: Superhub bouncing
 

Trouble is, as you might know, various departments jump on the fact that it IS an upstream network issue and immediately blame the local area network but as you state there is no immediate way of knowing where or how it is occurring so very difficult to diagnose.

Re: Superhub bouncing
 

whoa hang on there. everything else is fine, just the high downstream power levels! as iv already said, a 6db forward path attenuator should do the trick!

Re: Superhub bouncing
 

Really? because if I take my attenuator off my superhub it makes NO difference at all!

Re: Superhub bouncing
 

It will attenuate the Downstream levels your right in that respect, but it won't sort out the problem the OP is having

Re: Superhub bouncing
 

So the engineer came out on Saturday lunchtime: He fitted the 6dB attenuator and replaced the splitter in the grey box on the outside wall of the house as it had corroded pretty badly.

The power levels reduced too much (+2dB) so I've taken the attenuator off for now. The T3 and T4 timeouts still exist in the Event Log. The Superhub hasn't dropped connection since, but it still doesn't "feel" right. Webpages and YouTube videos can take an age to load and sometimes timeout. There doesn't appear to be evidence of packet loss either.

How can I resolve these T3 and T4 timeouts?

Re: Superhub bouncing
 

If you are saying that a downstream power level of 2dBmv is too low then you are mistaken. The closer to 0dBmv the better.

Re: Superhub bouncing
 

It brings the SNR down to 27-33dB though. Without the attenuator, the SNR is around 44dB.

Re: Superhub bouncing
 

So why didn't you say that in the first place or do you think just cherry picking parts of the stats will help you with your problem?

Re: Superhub bouncing
 

Nice hissy fit. :D

Re: Superhub bouncing
 

SNR is fine at 44dB.

Re: Superhub bouncing
 

Yup!:D

Re: Superhub bouncing
 

I know, but that's where there's a conflict:

Without the attenuator, power is high but SNR is good.
With the attenuator, power is good but SNR is low.

In any case, my primary concern is these T3 and T4 timeouts which I'd like to investigate. I believe these may be independent of the Superhub's levels. :confused:

Re: Superhub bouncing
 

Surely SNR shouldn't be dropping that much with just a 6dB attenuator fitted, mine doesn't.

I wonder if the attenuator is faulty?

---------- Post added at 17:13 ---------- Previous post was at 17:10 ----------

I think posting your full up and downstream stats are in order, preferably with the attenuator and without.

Re: Superhub bouncing
 

Saves "cherry picking!".

Re: Superhub bouncing
 

Without the attenuator is in the first post. I'll post them with the attenuator when I get in tonight.

Waaah! :bigcry:

Re: Superhub bouncing
 

Try and post as much info as you can, your first post doesn't show much at all, so include the quantity and frequency of T3 and T4's, what speed your supposed to be getting, whether your connecting wired or wireless, Up AND downstream power levels.

It will help diagnosing your issues that much easier for those in the know, and once armed with the right knowledge you can ring up and hopefully get it sorted.

Re: Superhub bouncing
 

Good one! Saves "cherry picking"!
https://www.cableforum.co.uk/images/local/2011/02/1.jpg

https://www.cableforum.co.uk/images/local/2015/12/3.gif

Re: Superhub bouncing
 

It must be a faulty attenuator or its not screwed in tight

Re: Superhub bouncing
 

:D

Re: Superhub bouncing
 

No.No,No!

You got it wrong! It should be "wine, wine, wine!

Hic!

https://www.cableforum.co.uk/images/...2011/04/74.gif

Re: Superhub bouncing
 

Okay, attenuator back on:

Downstream
Power: +3dB
SNR: +44dB

Upstream
Power: +42dB

...so it seems fine for now. Except for the new packet loss symptom.

http://www.pingtest.net/result/35719897.png
http://www.pingtest.net/result/35722741.png
http://www.pingtest.net/result/35722782.png

Re: Superhub bouncing
 

make sure the firewall and ip flood detection are turned off on the superhub

go on advanced settings and on services and untick the two boxes, click apply, run pingtest and you will have 0% packet loss

Re: Superhub bouncing
 

:erm: Already had them turned off. Should've said.

Re: Superhub bouncing
 

Can I refer you back to post #27

Re: Superhub bouncing
 

Good shout

Re: Superhub bouncing
 

https://www.cableforum.co.uk/images/...011/03/115.png

https://www.cableforum.co.uk/images/...011/03/116.png

https://www.cableforum.co.uk/images/...011/03/117.png

Connected with wires.

Re: Superhub bouncing
 

That's a bit more like it, now hopefully the peeps that understand these things can make a more informed opinion.

From the little I know, I believe T4 timeouts are indicative of a problem and would cause interruption in your service.

A quick google found

T3 and T4 Timeouts

I wanted to close this topic with a discussion on T3 and T4 timeouts as I have received many questions on “what causes T3 and T4 timeouts?� Fundamentally, a T3 timeout occurs when the cable modem fails to receive a RNG-RSP from the CMTS within 200 msec (after sending a RNG-REQ). A T4 timeout occurs when a cable modem fails to receive a RNG-REQ transmit grant MAP from the CMTS within 35 sec on the downstream channel (after receiving the previous RNG-RSP). There are number of reasons that these could occur and I will list a couple below for each and help guide you the root cause, but understand this is not and exhaustive list.

T3 Timeout No RNG-RSP in 200 msec – Typically an Upstream Problem

Most likely cause is upstream impairments preventing the RNG-REQ from reaching the CMTS, therefore the CMTS never transmits a RNG-RSP
May occur because the RNG-REQs from multiple cable modems collided, again the CMTS does not receive the RNG-REQ (now from multiple modems) and fails to process multiple RNG-RSP messages resulting in multiple T3 timeouts
CMTS over-utilization – unable to process RNG-REQ and/or RNG-RSP within T3 time frame (200 msec)
Can also be a downstream problem due to plant impairments – i.e. RNG-RSP is transmitted, but corrupted in route and the cable modem never receives the message
Look for low MER at the cable modem
T4 Timeout No RNG-REQ Grant MAP Received by Cable Modem in 35 sec – Typically a Downstream Problem

T4 timeouts can usually be identified with downstream impairments causing the cable modem to miss receiving the RNG-REQ grant MAP transmitted to it
If T4 errors are impacting many modems off of a common leg, trouble shoot that leg
If T4 errors are just associated with one modem, look for low MER/level at that modem
T4 timeouts can also be associated with a CMTS that has extremely high utilization i.e. >95% depending on the vendor and firmware version
Rule of thumb for CMTS utilization is 80% to allow for peak usage periods
It is highly unlikely that T4 timeouts are associated with any upstream impairments
A final note, T3 and T4 impairments are always within the DOCSIS network inclusive of the CMTS and cable modems. In fact it is the cable modems themselves that are doing the counting and alerting of T3 and T4 timeouts. This is one time that the IP network behind the CMTS is not to blame for any of these errors. No finger pointing on this one!

Re: Superhub bouncing
 

All very well for the explanation. T3's can occur naturally and can be discounted unless of course there are many within a short space of time.

Looking at the logs 1 T3 9hrs before the post does not a problem make.

I also notice the OP doesn't mind anyone seeing his modem MAC. NOT recommened!

Re: Superhub bouncing
 

I just gave his MAC to my neighbour to clone! Cheers!

















joking ;)

Re: Superhub bouncing
 

You can't clone DOCSIS 3 modems with just the MAC anyway. There's no harm in MAC addresses being posted.

Re: Superhub bouncing
 

Gotta love peak times:

https://www.cableforum.co.uk/images/...011/03/105.png