Cable Forum - Upstream Problems?

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Upstream Problems?

Hi,

I was having a few problems with 2MB BB on a SACM a few weeks ago. These cleared up, but have now come back again. Websites take ages to come through (from clicking a link), but when they do, they load v.quickly. Looking at the SACM, the DS light flashes v. rapidly, yet the US light is generaly out, and only flashes sparodicaly.

Any ideas would be greatfully recieved!

Re: Upstream Problems?

first try - clear your cache, I found many apparent 'latency' problems were due to trying to load dud links in the cache.

secondly, throttle the upload so it doesn't kill the downstream.

usual stuff about spyware/trojan detectors follows :angel:

Re: Upstream Problems?

I dont think there are any cache problems - i have tried it on several pcs behind a router, and one direct.

Re: Upstream Problems?

Quote:

Originally Posted by bdav

The downstream is flashing with the data that is passing I.E Web browsing, downloading files etc. The upstream will flash more when uploadingfiles etc. So the more you do of either the more they flash.

You need to give more info so we can help, the cable modems diagnostic page will help with the downstream and upstream levels and also the SNR. If you type in your address bar the following and put in root for username and root for password this will take you into it,(thats if you have an ambit modem of course). Type 192.168.100.1 this will take you into the diagnostics, get the relevent info post back here see if we can help.

Also you might find this helpful:http://homepage.ntlworld.com/robin.d...ps/signal.html

Re: Upstream Problems?

Hi,
These are the pages:
------------------------------Downst. Status----------------------------
Downstream Lock : Locked Downstream Frequency : 402750000 Hz Downstream Modulation : QAM64 Downstream Interleave Depth : 32 Downstream Receive Power Level : -11.8 dBmV Downstream SNR : 30.7 dB
-------------------Upstream Page----------------------
Upstream Channel ID : 4 Upstream Transmit Power Level : 45.50 dBmV Upstream Symbol Rate : 2560 Ksym/sec Upstream Frequency : 36800000 Hz Upstream Mini-Slot Size : 2
--------------Upstream Burst Page-------------------

Upstream Burst Descriptor

request(1) initialRanging(3) periodicRanging(4) shortData(5) longData(6) Modulation Type QPSK QPSK QPSK QPSK QPSK Differential Encoding Off Off Off Off Off Preamble Length 64 128 128 100 80 Preamble Offset 396 6 6 396 396 FEC T Bytes 0 5 5 3 9 FEC K Bytes 16 34 34 78 232 Scrambler Seed 338 338 338 338 338 Max Burst 0 0 0 35 254 Guard Time 8 48 48 25 134 Last Codeword Fixed Fixed Fixed Short Short Scrambler On On On On On
-----------------Rates-----------------------

Interface Rate

System Up Time 287 (Sec)
Packet Num Packet Rate Ethernet / In 873 3.041812 Ethernet / Out 3570 12.439024 Cable / In 3507 12.219512 Cable / Out 717 2.498258 USB / In 0 0.000000 USB / Out 0 0.000000

Thanks for the help!

Re: Upstream Problems?

Quote:

Originally Posted by bdav

Upstream Burst Descriptor

Interface Rate

Your downstream power levels is at -11.8db this should be around ideally -2.5Db-+2.5Db. This signal your modem is recieving is too low but is workable, but will cause intermittent problems. Do you have any forward attenuators on the input to the modem? or on the internal cable from Omni box outside,(grey box on outside wall) to the modem? This will be a small oblong shape device with the words forward attenuator and the amount in Db written on it.
Also go through check install for loose connections etc.

Re: Upstream Problems?

Downstream Status

Downstream Lock : Locked Downstream Frequency : 402750000 Hz Downstream Modulation : QAM64 Downstream Interleave Depth : 32 Downstream Receive Power Level : -7.5 dBmV Downstream SNR : 31.2 dB
Upstream Channel ID : 4 Upstream Transmit Power Level : 42.50 dBmV Upstream Symbol Rate : 2560 Ksym/sec Upstream Frequency : 36800000 Hz Upstream Mini-Slot Size : 2

This is directly into my wall box. No percieved speed increase. Do the levels look OK?

Re: Upstream Problems?

Quote:

Originally Posted by bdav

Downstream Status

Your Downstream level is 4db better, but should be ideally as already mentioned. But this should still work. How far away from where your modem was, to where your taking this downstream level from.

Re: Upstream Problems?

Quote:

Originally Posted by sollp

How far away from where your modem was, to where your taking this downstream level from.

Excuse me?

The connection was still poor on with the SACM directly connected to the cable and my Mac. Pages just take too long to load. (Tried Firefox and safari)