New UCD in effect

[Welshchris]

New UCD in effect

What does this actually mean in the modem log?

[whydoIneedatech]

New UCD in effect

What does this actually mean in the modem log?

I have searched online and this is the only article that had a match when I searched for "new UCD"

The below taken from this link http://ieeexplore.ieee.org/Xplore/login.jsp?url=/iel5/9179/29118/01312447.pdf?arnumber=1312447


https://www.cableforum.co.uk/images/local/2008/06/13.gif Rescheduling a cable-modem upstream channel after changing one or more of its properties
Carroll, M.
Communications, 2004 IEEE International Conference on
Volume 1, Issue , 20-24 June 2004 Page(s): 31 - 37 Vol.1
Digital Object Identifier 10.1109/ICC.2004.1312447
Summary: In a cable-modem network, a cable modem (CM) talks to a cable-modem termination system (CMTS) over a traditional cable-television network. In the DOCSIS protocol for such networks, the CMTS schedules the upstream (CM-to-CMTS) channels. DOCSIS also provides a mechanism that lets the CMTS change an upstream channel's properties at any time. Unfortunately, changing such a property usually invalidates the current upstream schedule. This paper describes a novel algorithm for rescheduling a DOCSIS upstream channel in response to a property change. The algorithm, which is in use in a real CMTS, has several important advantages: It is flexible, service preserving, and efficient.

[Ignitionnet]

Upstream Channel Descriptor describes the upstream channels, frequency, width, modulation, guard bands, etc.

If enabled the uBR can dynamically change some of these so if the channel you are on degrades a bit for example it can look for spare upstream spectrum to move the channel to, or drop modulation.

[whydoIneedatech]

Upstream Channel Descriptor describes the upstream channels, frequency, width, modulation, guard bands, etc.

If enabled the uBR can dynamically change some of these so if the channel you are on degrades a bit for example it can look for spare upstream spectrum to move the channel to, or drop modulation.

Was the above right at all, that I found on the net?

[caph]

Hi, my 3 months of pitiful 20mb speed seemed to be fixed last week and for the first time in months I was able to get over 10mb speed (even up around 19Mb sometimes!). However last night my speed took a nose dive to 0.5Mb and this morning is hovering around 0.3Mb. I checked the modem log last night and saw something odd. It is happening again this morning. Possibly causing my slow speed?

It's the "New UCD in Effect" happening every few minutes but no "on the fly change" with it that others seem to have. Do you think I've got a problem or it this normal?

Log:

First TimeLast TimePriorityDescription
Sat Jan 03 11:39:11 2009 Sat Jan 03 11:39:11 2009 Information (7)New UCD in effect
Sat Jan 03 11:36:24 2009 Sat Jan 03 11:36:24 2009 Critical (3)Started Unicast Maintenance Ranging - No Response received - ...
Sat Jan 03 11:26:22 2009 Sat Jan 03 11:26:22 2009 Information (7)New UCD in effect
Sat Jan 03 11:21:24 2009 Sat Jan 03 11:21:24 2009 Critical (3)Started Unicast Maintenance Ranging - No Response received - ...
Sat Jan 03 11:20:52 2009 Sat Jan 03 11:20:52 2009 Information (7)New UCD in effect
Sat Jan 03 11:20:27 2009 Sat Jan 03 11:20:27 2009 Critical (3)Started Unicast Maintenance Ranging - No Response received - ...
Sat Jan 03 11:19:36 2009 Sat Jan 03 11:19:36 2009 Information (7)New UCD in effect
Sat Jan 03 11:18:12 2009 Sat Jan 03 11:18:12 2009 Critical (3)Started Unicast Maintenance Ranging - No Response received - ...
Sat Jan 03 11:18:11 2009 Sat Jan 03 11:18:11 2009 Information (7)New UCD in effect
Sat Jan 03 11:02:39 2009 Sat Jan 03 11:02:39 2009 Critical (3)Started Unicast Maintenance Ranging - No Response received - ...
Sat Jan 03 11:01:23 2009 Sat Jan 03 11:01:23 2009 Information (7)New UCD in effect
Sat Jan 03 10:57:55 2009 Sat Jan 03 10:57:55 2009 Critical (3)Started Unicast Maintenance Ranging - No Response received - ...
Sat Jan 03 10:57:42 2009 Sat Jan 03 10:57:42 2009 Information (7)New UCD in effect
Sat Jan 03 10:56:58 2009 Sat Jan 03 10:56:58 2009 Critical (3)Started Unicast Maintenance Ranging - No Response received - ...
Sat Jan 03 10:56:50 2009 Sat Jan 03 10:56:50 2009 Information (7)New UCD in effect
Sat Jan 03 10:54:44 2009 Sat Jan 03 10:54:44 2009 Critical (3)Started Unicast Maintenance Ranging - No Response received - ...
Sat Jan 03 10:54:14 2009 Sat Jan 03 10:54:14 2009 Information (7)New UCD in effect
Sat Jan 03 10:52:50 2009 Sat Jan 03 10:52:50 2009 Critical (3)Started Unicast Maintenance Ranging - No Response received - ...
Sat Jan 03 10:34:42 2009 Sat Jan 03 10:34:42 2009 Information (7)New UCD in effect
Sat Jan 03 10:33:26 2009 Sat Jan 03 10:33:26 2009 Critical (3)Started Unicast Maintenance Ranging - No Response received - ...
Sat Jan 03 10:33:21 2009 Sat Jan 03 10:33:21 2009 Information (7)New UCD in effect
Sat Jan 03 10:33:08 2009 Sat Jan 03 10:33:08 2009 Critical (3)Started Unicast Maintenance Ranging - No Response received - ...
Sat Jan 03 10:32:36 2009 Sat Jan 03 10:32:36 2009 Information (7)New UCD in effect
Sat Jan 03 10:30:56 2009 Sat Jan 03 10:30:56 2009 Critical (3)Started Unicast Maintenance Ranging - No Response received - ...
Sat Jan 03 10:30:41 2009 Sat Jan 03 10:30:41 2009 Information (7)New UCD in effect
Sat Jan 03 10:29:58 2009 Sat Jan 03 10:29:58 2009 Critical (3)Started Unicast Maintenance Ranging - No Response received - ...
Sat Jan 03 10:29:55 2009 Sat Jan 03 10:29:55 2009 Information (7)New UCD in effect
Sat Jan 03 10:28:42 2009 Sat Jan 03 10:28:42 2009 Critical (3)Started Unicast Maintenance Ranging - No Response received - ...
Sat Jan 03 10:28:34 2009 Sat Jan 03 10:28:34 2009 Information (7)New UCD in effect
Sat Jan 03 10:28:04 2009 Sat Jan 03 10:28:04 2009 Critical (3)Started Unicast Maintenance Ranging - No Response received - ...
Sat Jan 03 10:26:52 2009 Sat Jan 03 10:26:52 2009 Information (7)New UCD in effect
Sat Jan 03 10:26:48 2009 Sat Jan 03 10:26:48 2009 Critical (3)Started Unicast Maintenance Ranging - No Response received - ...

[Joxer]

A look at the upstream (and downstream) power levels might be useful - type 192.168.100.1 into a browser. you might want to refresh the page now and again to see if it changes, unless you have a webstar, they refresh automatically.

[caph]

Upstream has always been high at around 56.5 but seems to have nudged up to 58 recently. I'm ex-NTL and I've got a new black Virgin branded modem.

Upstream Lock : Locked
Upstream Channel ID : 2
Upstream Frequency : 29200000 Hz
Upstream Modulation : QAM16
Upstream Symbol Rate : 2560 Ksym/sec
Upstream transmit Power Level : 58.0 dBmV
Upstream Mini-Slot Size : 2


Downstream Lock : Locked
Downstream Channel Id : 0
Downstream Frequency : 402750000 Hz
Downstream Modulation : QAM256
Downstream Symbol Rate : 5360.537 Ksym/sec
Downstream Interleave Depth : taps32Increment4
Downstream Receive Power Level : 1.9 dBmV
Downstream SNR : 38.0 dB

[Joxer]

Upstream power is too high - you need a tech.

[caph]

Joxer, thanks for your input but I've been round and round in circles over this one and I keep getting told contradictory things by people on this forum and by CS over the phone and by second line on the newsgroup. In fact you yourself told me off in another thread for questioning whether anyone actually knows what these maximums are and pointed me in the direction of the sticky thread on the subject which contradicts itself. Ignition states that QAM16 requires max 55, but BBKing states that Ambit can handle 61! I am on QAM16 and have an Ambit so where does that leave me?

I'm not having a go, it's just that everyone seems to tell me different things and when I ring CS I'm lucky if I speak to someone who knows how to read my upstream power level off their computer. It's been driving me crazy. Even second line support on the newsgroup have refused to send out an engineer because they reckon 58 is the maximum and won't book an engineer until I go over that.

I guess what you're saying is that the constant new UCD messages are being caused by the upstream power being too high. That I can believe but the question is can I get any first or second line CS to believe it. I'll give them a ring (mentally preparing myself first) ...

Thanks for replying.

[Joxer]

Good luck.

As usual in life there is a difference between what the specification says and what actually happens in practice.

they reckon 58 is the maximum and won't book an engineer until I go over that.

Thats a bit odd, some modems will never show it higher than that, even when it is.

'm lucky if I speak to someone who knows how to read my upstream power level off their computer

I hear a rumour (a rumour, mind) that one of the calls centres haven't been trained how to do this, it wouldn't surprise me if it was true.

I didn't mean to tell you off before, need to use appropriate emoticons more.:dunce:

[caph]

I didn't mean to tell you off before, need to use appropriate emoticons more.:dunce:

I was at the end of my tether and venting. Plus I hadn't actually read the sticky! You did me a favour before I made even more of a fool of myself. ;)

Upstream has just hit 59.5 so it looks like it's definitely the culprit.

[caph]

Just speed tested at 14Mb with an upstream power of 58 and guess what, the UCD events stopped at around 6pm. It definitely seems like the chronic speed was related to this UCD problem and not the upstream power.

Engineer's going to come out anyway.

Anyone else experienced extremely slow speeds with recurring UCD events?

[Joxer]

I think what is happening is the upstream power level is fluctuating - when it gets too high the u/s channel loses lock and has too try again - hence the UCD event, it can be caused by overheating RF amplifiers so it working better in the cooler evenings would make sense (don't quote me on that if it goes off again though :) ).

[Ignitionnet]

Modems increase their upstream transmit power in response to a couple of things, either they are not loud enough when they hit the uBR so it asks them to increase transmit power to try and reach target level, or they are trying to go over a high level of noise.

Also when transmitting power level is too high it can introduce distortion causing a poor signal quality to be received. Modems should not go above 55dBmV when using 16QAM. Things might work ok, intermittently, with high power but it's a far from good situation.

I'm not sure about the heat thing and it seems rather unlikely. I'm wondering if, going by what you said about last week being better, there's something in your local area that's causing a noise issue, and last week was better as they weren't at work / play. That or the return path in your area isn't properly lined up.

Either way the issue will come back. The UCD messages were caused by losing upstream sync, and 58dBmV is too high.

Consider posting on the newsgroups perhaps.

[caph]

My exchange (Basford, Nottingham - BASF3) is currently being upgraded to 50Mb. Apparently the power levels are all over the place while this is going on which explains my "New UCD in effect" messages. I've just got to hang in there while the hardware gets swapped. Could be weeks apparently. Oh well.

Thanks for everyone's help.

[Axegrinder]

Has anyone noticed in Nottingham that there internet and TV has gone down today?

[General Maximus]

my internet has been fine all day (Lincoln falls under Nottingham apparently) and I am pleased to hear about the UCD messages. When this thread was started last week I checked my modem log and noticed I had the same messages but everything has been fine so i didn't think anything of it. If the messages are a result of the network being upgraded to 50mbit then I am very excited. Hopefully they'll send us all emails as soon as it is done so we can get the ball rolling :)

[Axegrinder]

^If your in Lincoln LN6, theres an outage alert for that area.

[General Maximus]

you sure know how to make a man cry :((((((((((((((((((((((((((((((((( When you say an alert does that mean it is definitely "going to" happen or that if i was going to be affected i would have lost my connection already. I am in LN6 but my connection has been 100% all day.

[Zhadnost]

I wish new upgrades were the cause of the problems I'm having today.

Losing sync regularly (though stopped around 4pm). Power levels all over the place, modem changing it's mind which downstream to sync with.

Engineer coming tomorrow (recommended by ng), I bet he doesn't do anything.

[xocemp]

http://status-cable.virginmedia.com/vmstatus/serviceissue.do?ticket=879064

You may be on different cmts or card on the cmts that has the issue. I'd be more inclined to think different cmts.

[caph]

My exchange (Basford, Nottingham - BASF3) is currently being upgraded to 50Mb. Apparently the power levels are all over the place while this is going on which explains my "New UCD in effect" messages. I've just got to hang in there while the hardware gets swapped. Could be weeks apparently. Oh well.

Thanks for everyone's help.

Why don't second level support know this? It took an engineer at my home to phone his boss who was up to his arms in it in the exchange to find this out! Why can't Virgin communicate internally?

[Instincts]

Nottingham has been 'changing the cables' accordind to tech support since the 29th and there is no date been set for the completion, he said at least another 2 weeks!! ive been getting 300kbps connection mostly!!

[AppleSauce]

Not had any modem logs in ages, is this normal? lol

[caph]

New UCD messages still happening.

2nd level support now say that the engineer was wrong and that he can correct an upstream power level problem. Reading around this forum it seems that's not right and the engineer is correct i.e. the upstream can only be changed by network and the taps in the DP are of various downstream and not upstream power leves. Is this right? They want to send out another engineer but I'm a bit loathe to take time off work for an engineer visit who's going to tell me that he can't do anything except escalate it to the network team.

[Ignitionnet]

New UCD messages still happening.

2nd level support now say that the engineer was wrong and that he can correct an upstream power level problem. Reading around this forum it seems that's not right and the engineer is correct i.e. the upstream can only be changed by network and the taps in the DP are of various downstream and not upstream power leves. Is this right? They want to send out another engineer but I'm a bit loathe to take time off work for an engineer visit who's going to tell me that he can't do anything except escalate it to the network team.

The taps in the DP affect both up and downstream power.

[caph]

So do you know why an engineer would say that he could not alter the upstream, only the downstream? Surely engineers are able to open and tinker with the local DP?

Any idea why he thought that upstream power level was the same for all people on my local DP and changing it would affect everyone in my area as well as cascading on to other DPs?

[caph]

A final update on the UCD messages from me. Persistent lack of knowledge and/or can't be botheredness has meant that several support engineer visits later, my upstream power level has stayed at around 60db.

Everyone thought (and reasonably so I thought) it was causing my Critical Unicast Maintenance Ranging non-responses and the new UCD in effect. It turns out it wasn't. It happened for approximately 10 days (supposedly while the 50mb upgrade was happening to my "exchange") and then it stopped. I've not had any problems for several days since and I'm averaging 12mb at peak times on my heavily oversubscribed UBR.

I guess the moral is that a 60db upstream power level on an ambit in an ex-ntl area is nothing to get your knickers in a twist about.

[Ignitionnet]

So do you know why an engineer would say that he could not alter the upstream, only the downstream? Surely engineers are able to open and tinker with the local DP?

Any idea why he thought that upstream power level was the same for all people on my local DP and changing it would affect everyone in my area as well as cascading on to other DPs?

No, yes, no and no respectively, unless you were already on the lowest attenuation tap in your cabinet, but:

1) Yes they can change your upstream power by changing your tap in the cabinet.
2) Yes they are able to open the cabinet your tap is in.
3) No, no idea why he said that power level was the same. It would vary both depending on tap rating and on distance from the cabinet.
4) No idea why doing something to your connection would affect everyone in your area and cascade on to other areas.

Either you misunderstood what he was saying to you or he wasn't sure of the questions you asked, or he wasn't entirely sure about things.

By DP I referred to Distribution Point, the cabinet where the taps your connection runs off live.

[cabsandy]

A final update on the UCD messages from me. Persistent lack of knowledge and/or can't be botheredness has meant that several support engineer visits later, my upstream power level has stayed at around 60db.

Everyone thought (and reasonably so I thought) it was causing my Critical Unicast Maintenance Ranging non-responses and the new UCD in effect. It turns out it wasn't. It happened for approximately 10 days (supposedly while the 50mb upgrade was happening to my "exchange") and then it stopped. I've not had any problems for several days since and I'm averaging 12mb at peak times on my heavily oversubscribed UBR.

I guess the moral is that a 60db upstream power level on an ambit in an ex-ntl area is nothing to get your knickers in a twist about.

There's a few things wrong in this thread which I'll try to correct

UCD-Upstream channel descriptor-broadcast on the downstream for every upstream in that MAC domain. A MAC domain consists of a downstream and at least one upstream.In VM usually between 1 and 4. The UCD doesnt change-its not dynamic.It is set in stone and does not change when the prevailing network conditions do

Upstream power levels- DOCSIS states +55dBmV for 16QAM and QPSK +58dBmV. 60dBmV is far too high-take me word for it. Critical Unicast Maintenance Ranging non-responses mean something is up-it might not be the power level.It may have been disconnections in the hub during the upgrades but nobody can say without looking any further.Also, and this is a common mistake, modems don't transmit higher when there is a noise issue. The modem power is controlled by the UBR, not the network.Think of it as a long line AGC circuit

Taps/DP-an engineer could change the power levels by changing the tap values but he shouldn't DOCSIS has a window of +8 to +58 (QPSK). If your modem is that high, there is a problem (somewhere).It should not be frigged by changing the drop cable onto a different tap! :dunce:

HTH

[Ignitionnet]

Hello Sir!

UCD can change depending on the CMTS card you are using and how it's configured, some cards contain spectrum analysers (MC16S for example) and can be configured to move or modify modulations on upstreams when network conditions change, with the result that the UCD becomes dynamic.

Modems can transmit briefly higher due to noise until they get heard by the CMTS which sends the required power adjustment to calm them down, though it's not a longer term thing. Depends on how the modem response to its' station maintenance not being responded to.

Appreciate that things shouldn't be frigged through a tap switch and the network should be checked and if needed lined up.

Great to have you here and thanks for the input and corrections, appreciate your knowledge :)

[Ignitionnet]

If you have the time actually I'd like to discuss a couple of things regarding 50Mbit with you outside of the public eye - would you object to a private message?

[cabsandy]

Hello Sir!

UCD can change depending on the CMTS card you are using and how it's configured, some cards contain spectrum analysers (MC16S for example) and can be configured to move or modify modulations on upstreams when network conditions change, with the result that the UCD becomes dynamic.

Modems can transmit briefly higher due to noise until they get heard by the CMTS which sends the required power adjustment to calm them down, though it's not a longer term thing. Depends on how the modem response to its' station maintenance not being responded to.

Appreciate that things shouldn't be frigged through a tap switch and the network should be checked and if needed lined up.

Great to have you here and thanks for the input and corrections, appreciate your knowledge :)

The UCD can change across CMTS, true, but once there in there, there set. What I meant was that they don't change "on the fly" ;)

Modems will transmit higher until their heard but if their being heard and there is a rise in noise, they don't start transmitting higher because of the noise. The tx level stays the same, hence why you'll see a drop in CNR and SNR. Modems will normally adjust their power during the initial stages of ranging and then only small increments will follow :)

[Ignitionnet]

The UCD can change across CMTS, true, but once there in there, there set. What I meant was that they don't change "on the fly" ;)

Not in VM's case but they can - some CMTS cards come with their own analysers built in and make the best use they can of the spectrum, so if an upstream is on a noisy frequency they'll move it elsewhere or modify burst parameters causing a change in the UCD.

Modems will transmit higher until their heard but if their being heard and there is a rise in noise, they don't start transmitting higher because of the noise. The tx level stays the same, hence why you'll see a drop in CNR and SNR. Modems will normally adjust their power during the initial stages of ranging and then only small increments will follow :)

Absolutely though occasionally due to issues there'll be times when modems transmit considerably higher or lower - causing power adjustment counter at the CMTS to increment.

What I meant was that modems can start transmitting higher if the CMTS stops responding to periodic station maintenance.

Both agreeing with you and disagreeing with you I guess. I would appreciate a chance to discuss the DOCSIS 3 overlay with you though at some point.