Basic Internet Connectivity And Modem Help

[ACECORP]

Ever since July 7th, my internet download speed dropped from being very fast to operating at speeds from 0.05 Mbps to 0.40 Mbps.

This is exponentially slower than it is supposed to be.

My upload speed remains unchanged and fast at 3.89 Mbps to 4.98 Mbps

I have a service call scheduled for Saturday where a technician will come onsite, but I am confident that the problem should be  detectable and resolvable by Comcast without needing to send a technician to my local.  I believe the problem to be somewhere within the Comcast infrastructure because nothing changed at my local. I also work in the IT industry.

I have posted my cable modem’s configuration and SNR information below.

Does the cable modem info shown below provide any insight as to the specific nature of the problem?

Is there a larger comcast network issue that needs to be fixed?

Cable Modem Status

Item                                                       Status                     Comments

Acquire a Downstream Channel      741000000 Hz     Locked

Connectivity State                              OK                          Operational

Boot State                                             OK                          Operational

Security                                                 Enabled                 BPI+

Cable Modem Downstream

Downstream Lock :                             Locked

Downstream Channel Id :  8

Downstream Frequency : 741000000 Hz

Downstream Modulation :  QAM256

Downstream Symbol Rate : 5360.537 Ksym/sec

Downstream Interleave Depth :       taps32Increment4

Downstream Receive Power Level : -5.2 dBmV

Downstream SNR : 29.7 dB

Cable Modem Upstream

Upstream Lock : Locked

Upstream Channel ID :      2

Upstream Frequency :        29400000 Hz

Upstream Modulation :      QPSK

Upstream Symbol Rate :   5120 Ksym/sec

Upstream transmit Power Level : 48.2 dBmV

Upstream Mini-Slot Size : 4

Cable Modem Upstream Burst

                Req         Init Maint              Per Maint              Adv Short              Adv Long              Adv UGS

                (1)           (3)           (4)           (9)           (10)         (11)

Modulation Type                QPSK     QPSK     QPSK     64QAM                 64QAM                 64QAM

Differential Encoding         Off          Off          Off          Off          Off          Off

Preamble Length 64           640         384         104         104         104

Preamble Value Offset       652         0              0              724         724         724

FEC Error Correction (T)    0              5              5              12           16           12

FEC Codeword Information Bytes (k)            16           34           34           81           223         81

Scrambler Seed    338         338         338         338         338         338

Maximum Burst Size          0              0              0              11           193         219

Guard Time Size  8              48           48           8              8              8

Last Codeword Length       Fixed      Fixed      Fixed      Short      Short      Short

Scrambler on/off On           On           On           On           On           On

Network Access :                 Allowed

Maximum Downstream Data Rate :               16500000

Maximum Upstream Data Rate :    2200000

Maximum Upstream Channel Burst :             5000000

Maximum Number of CPEs :           1

Configuration FileName : d11_m_u10c018_silver_c01.cm

Modem Capability :           Concatenation Enabled, Fragametation Enabled, PHS Enabled

Cable Modem Event Log

First Time              Last Time              Priority   Description

Thu Jul 12 06:19:02 2012                 Thu Jul 12 06:19:02 2012                 Critical (3)             Started Unicast Maintenance Ranging - No Response received - ...

Thu Jul 12 00:01:52 2012                 Thu Jul 12 00:01:52 2012                 Critical (3)             REG RSP not received

Thu Jul 12 00:01:40 2012                 Thu Jul 12 00:01:40 2012                 Critical (3)             Started Unicast Maintenance Ranging - No Response received - ...

Wed Jul 11 23:07:28 2012                Wed Jul 11 23:07:28 2012                Critical (3)             REG RSP not received

Wed Jul 11 23:06:53 2012                Wed Jul 11 23:06:53 2012                Critical (3)             No Ranging Response received - T3 time-out

Wed Jul 11 23:06:45 2012                Wed Jul 11 23:06:45 2012                Critical (3)             SYNC Timing Synchronization failure - Failed to acquire FEC f...

Wed Jul 11 23:06:30 2012                Wed Jul 11 23:06:30 2012                Critical (3)             SYNC Timing Synchronization failure - Failed to receive MAC S...

Wed Jul 11 23:05:59 2012                Wed Jul 11 23:05:59 2012                Critical (3)             No Ranging Response received - T3 time-out

Wed Jul 11 23:05:41 2012                Wed Jul 11 23:05:41 2012                Critical (3)             Received Response to Broadcast Maintenance Request, But no Un...

Wed Jul 11 23:05:09 2012                Wed Jul 11 23:05:09 2012                Critical (3)             Started Unicast Maintenance Ranging - No Response received - ...

Wed Jul 11 23:04:35 2012                Wed Jul 11 23:04:35 2012                Critical (3)             SYNC Timing Synchronization failure - Failed to receive MAC S...

Wed Jul 11 23:04:28 2012                Wed Jul 11 23:04:28 2012                Critical (3)             Started Unicast Maintenance Ranging - No Response received - ...

Wed Jul 11 23:04:26 2012                Wed Jul 11 23:04:26 2012                Critical (3)             SYNC Timing Synchronization failure - Failed to receive MAC S...

Wed Jul 11 23:03:05 2012                Wed Jul 11 23:03:05 2012                Critical (3)             Started Unicast Maintenance Ranging - No Response received - ...

Wed Jul 11 23:00:35 2012                Wed Jul 11 23:00:35 2012                Critical (3)             SYNC Timing Synchronization failure - Failed to receive MAC S...

Wed Jul 11 23:00:25 2012                Wed Jul 11 23:00:25 2012                Critical (3)             Started Unicast Maintenance Ranging - No Response received - ...

Time Not Established         Time Not Established         Critical (3)             Started Unicast Maintenance Ranging - No Response received - ...

Wed Jul 11 23:06:45 2012                Wed Jul 11 23:06:45 2012                Critical (3)             SYNC Timing Synchronization failure - Failed to acquire QAM/Q...

Wed Jul 11 22:33:24 2012                Wed Jul 11 22:33:24 2012                Critical (3)             TFTP Failed - OUT OF ORDER packets

Wed Jul 11 22:32:54 2012                Wed Jul 11 22:32:54 2012                Critical (3)             Started Unicast Maintenance Ranging - No Response received - ...

Wed Jul 11 22:28:30 2012                Wed Jul 11 22:28:30 2012                Critical (3)             No Ranging Response received - T3 time-out

Wed Jul 11 22:27:57 2012                Wed Jul 11 22:27:57 2012                Critical (3)             Received Response to Broadcast Maintenance Request, But no Un...

Wed Jul 11 22:27:25 2012                Wed Jul 11 22:27:25 2012                Critical (3)             Started Unicast Maintenance Ranging - No Response received - ...

Time Not Established         Time Not Established         Critical (3)             Started Unicast Maintenance Ranging - No Response received - ...

Sat Jul 07 22:38:46 2012 Sat Jul 07 22:38:46 2012 Critical (3)             REG RSP not received

[EG]

The downstream SNR is out of spec which can mean that there is some noise ingress in the line somewhere. Let the tech come out and check it. If the premise facing techs can't find / fix the issue at your home (including a modem swap if you are renting it) it is he who is responsible to escalate it to the line / maintenance dept. techs to investigate the neighborhood infrastructure.

[Jessica_Donahoe]

I been having the same problem. Slow download, normal upload. What is a good range for SNR?

Downstream-

Frequency: 717000000 Hz
SNR: 27.6 dB
Power Level: -9.7 dBmV

Upstream-

Channel ID 6
Frequency: 37000000 Hz
Power: 50.9 dBmV

Log-

2012-07-12 20:42:40 3-Critical R005.0 Started Unicast Maintenance Ranging - No Response received - T3 time-out
1970-01-01 00:00:08 6-Notice M571.1 Ethernet link up - ready to pass packets
1970-01-01 00:00:31 3-Critical R002.0 No Ranging Response received - T3 time-out
1970-01-01 00:00:24 6-Notice M572.0 Ds Lock Failed - Reinitialize MAC...
1970-01-01 00:00:24 3-Critical T001.0 SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing
1970-01-01 00:00:23 6-Notice M572.0 T1 No Ucd Timeout - Reinitialize MAC...
1970-01-01 00:00:23 3-Critical U001.0 No UCD's Received - Timeout
1970-01-01 00:00:08 6-Notice M571.1 Ethernet link up - ready to pass packets
2012-07-12 16:19:10 6-Notice M573.0 Modem Is Shutting Down and Rebooting...
2012-07-12 16:19:10 3-Critical R004.0 Received Response to Broadcast Maintenance Request, But no Unicast Maintenance o
2012-07-12 16:18:47 3-Critical T004.0 SYNC Timing Synchronization failure - Failed to receive MAC SYNC frame within ti
2012-07-12 16:18:12 3-Critical R005.0 Started Unicast Maintenance Ranging - No Response received - T3 time-out

[EG]

---

Jessica_Donahoe wrote:

I been having the same problem. Slow download, normal upload. What is a good range for SNR?

Downstream-

Frequency: 717000000 Hz
SNR: 27.6 dB
Power Level: -9.7 dBmV

Upstream-

Channel ID 6
Frequency: 37000000 Hz
Power: 50.9 dBmV

---

The downstream SNR is not a range. It should be at least 33 dB, and higher is better. Yours is way out of spec and the downstream power is weak and the upstream is marginal. You have connection quality issues. Follow the same advice.

[Jessica_Donahoe]

It is very sporatic.

The status page on my modem doesnt change, but my experience will greatly.

20 minutes ago, when everything was slow.

http://speedtest.net/result/2060846973.png

Just now, back to normal

http://speedtest.net/result/2060863883.png

I feel like something must be going on besides the signal on the line.

[EG]

---

Jessica_Donahoe wrote:

It is very sporatic.

I feel like something must be going on besides the signal on the line.

---

It probably fluctuates intermittenly.

[Jessica_Donahoe]

I am mistaken. The signal is higher now.

Is there anything I can do myself? Inspect or replace my cable connections? What number should I call?

Downstream Value

Frequency 717000000 Hz
Signal To Noise Ratio 36.2 dB
Power Level -9.6 dBmV

Upstream Value

Channel ID 6
Frequency 37000000 Hz
Power 50.7 dBmV

[EG]

Only the SNR is better. The power levels are still marginal. Noise ingress can indeed be intermittent and tough to find. Are there any excess/unneeded coax cable splitters in the line leading to the modem that can be eliminated/re-configured ?

If there aren't any uneeded splitters that can be eliminated and if your coax wiring setup can't be reconfigured so that there is a single two way splitter connected directly off of the drop from the street/pole with one port feeding the modem and the other port feeding the rest of the house/equipment with additional splits as needed and you've checked all the wiring and fittings for integrity and tightness and refresh them by taking them apart then putting them back together again, then perhaps it's best to book a tech visit to investigate and correct. Call 1-800-comcast.

[Jessica_Donahoe]

The cable goes directly from the modem into the wall, though there may be splitters I can't see.

1800 Comcast it is. Thanks for the diagnosis!

[EG]

Good luck with it !