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New Visitor
teresamrabon931
Posts: 3
Registered: ‎02-04-2013

Holy Lag Spikes Batman

I'm experiencing systemic lag spikes, I have no idea what the issue is. I even subscribed to Xfinity blast hoping it was a bandwidth issue but nope. I get 50 Mbps but it is not sustained. I experience sharp drops in bandwidth for brief periods which results in lag spikes during gaming and interrupts in streaming buffer for online video.

 

The cable television signal is the same. I get brief but sporadic pixilation and blank screens

The techs have come out twice. They replaced the modem and even replaced connections and removed unnecessary splitters throughout the house. They tested the signal and I observed. To the wall I get 10 db which is awesome. If it’s not the signal and it’s not the bandwidth what the heck is going on? I’m willing to help where I can but sheesh. I pay a lot for this service or should I say lack thereof.

 

I hate to say it but I just switched to Xfinity from Verizon FiOS two wweks ago and I never had this problem. Same personal computer and Xbox, same configuration... I'm getting my rear end kicked in Black Ops 2 now = no fun : (

 

Make and Model:

Technicolor  TC8305C

 

Contacted Comcast:

Comcast techs visited twice. They replaced modem, removed splitters and replaced all connectors. They also verified signal on coax to house and at modem.

 

What are lights doing?

The modem lights are all lit solid

 

 

Downstream                                  Channel Bonding Value

Index      1              2              3              4              5              6              7              8

Lock Status            Locked   Locked   Locked   Locked   Locked   Locked   Locked   Locked

Frequency             609 MHz                573 MHz                579 MHz                585 MHz                591 MHz                597 MHz                603 MHz                615 MHz

SNR         41.3 dB  40.9 dB  40.4 dB  40.8 dB  40.8 dB  40.9 dB  40.8 dB  40.3 dB

Power    9.7 dBmV               9.8 dBmV               9.5 dBmV               9.5 dBmV               9.4 dBmV               9.5 dBmV               9.3 dBmV               9.6 dBmV

Modulation           QAM256                QAM256                QAM256                QAM256                QAM256                QAM256                QAM256                QAM256

------------------------------------------------------------------------------------------------------------------------------------------

Upstream               Channel Bonding Value

Index      1              2              3              4

Lock Status            Locked   Locked   Locked   Not locked

Frequency             33 MHz  27 MHz  22 MHz 

Symbol Rate          5120 Ksym/sec     5120 Ksym/sec     2560 Ksym/sec    

Power Level          39.8 dBmV             39.8 dBmV             39.8 dBmV            

Modulation           ATDMA  ATDMA  TDMA    

Channel ID             4              5              6             

------------------------------------------------------------------------------------------------------------------------------------------------

 

 

System Logs:Last month

 

Time                      Priority         Description

 

Sun Feb 03 20:35:57 2013  Critical (3)     Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=8c:04:ff:36:ef:e6;CMTS-MAC=00:01:5c:32:96:88;CM-QOS=1.1;CM-VER=3.0;

 

Fri Feb 01 10:30:43 2013  Notice (6)       TLV-11 - unrecognized OID;CM-MAC=8c:04:ff:36:ef:e6;CMTS-MAC=00:01:5c:32:96:88;CM-QOS=1.1;CM-VER=3.0;

 

Fri Feb 01 10:30:42 2013  Warning (5)      DHCP WARNING - Non-critical field invalid in response ;CM-MAC=8c:04:ff:36:ef:e6;CMTS-MAC=00:01:5c:32:96:88;CM-QOS=1.1;CM-VER=3.0;

 

Fri Feb 01 10:30:29 2013  Notice (6)       Overriding MDD IP initialization parameters; IP provisioning mode = IPv4

 

Fri Feb 01 10:30:15 2013  Critical (3)     Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=8c:04:ff:36:ef:e6;CMTS-MAC=00:01:5c:32:96:88;CM-QOS=1.1;CM-VER=3.0;

 

Fri Feb 01 10:29:58 2013  Critical (3)     SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=8c:04:ff:36:ef:e6;CMTS-MAC=00:01:5c:32:96:88;CM-QOS=1.1;CM-VER=3.0;

 

Fri Feb 01 10:29:43 2013  Critical (3)     Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=8c:04:ff:36:ef:e6;CMTS-MAC=00:01:5c:32:96:88;CM-QOS=1.1;CM-VER=3.0;

 

Fri Feb 01 10:29:43 2013  Critical (3)     SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=8c:04:ff:36:ef:e6;CMTS-MAC=00:01:5c:32:96:88;CM-QOS=1.1;CM-VER=3.0;

 

Fri Feb 01 10:29:42 2013  Warning (5)      MDD message timeout;CM-MAC=8c:04:ff:36:ef:e6;CMTS-MAC=00:01:5c:32:96:88;CM-QOS=1.1;CM-VER=3.0;

 

Fri Feb 01 10:29:42 2013  Critical (3)     Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=8c:04:ff:36:ef:e6;CMTS-MAC=00:01:5c:32:96:88;CM-QOS=1.1;CM-VER=3.0;

 

Fri Feb 01 10:29:42 2013  Critical (3)     SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=8c:04:ff:36:ef:e6;CMTS-MAC=00:01:5c:32:96:88;CM-QOS=1.1;CM-VER=3.0;

 

Fri Feb 01 10:29:36 2013  Warning (5)      MDD message timeout;CM-MAC=8c:04:ff:36:ef:e6;CMTS-MAC=00:01:5c:32:96:88;CM-QOS=1.1;CM-VER=3.0;

 

Fri Feb 01 10:29:36 2013  Critical (3)     SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=8c:04:ff:36:ef:e6;CMTS-MAC=00:01:5c:32:96:88;CM-QOS=1.1;CM-VER=3.0;

 

Thu Jan 31 22:46:07 2013  Warning (5)      TEK Invalid - Invalid Key Sequence Number;CM-MAC=8c:04:ff:36:ef:e6;CMTS-MAC=00:01:5c:32:96:88;CM-QOS=1.1;CM-VER=3.0;

 

Wed Jan 30 19:27:52 2013  Critical (3)     Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=8c:04:ff:36:ef:e6;CMTS-MAC=00:01:5c:32:96:88;CM-QOS=1.1;CM-VER=3.0;

 

Tue Jan 29 01:16:25 2013  Notice (6)       TLV-11 - unrecognized OID;CM-MAC=8c:04:ff:36:ef:e6;CMTS-MAC=00:01:5c:32:96:88;CM-QOS=1.1;CM-VER=3.0;

 

Mon Jan 28 19:29:08 2013  Notice (6)       TLV-11 - unrecognized OID;CM-MAC=8c:04:ff:36:ef:e6;CMTS-MAC=00:01:5c:32:96:88;CM-QOS=1.1;CM-VER=3.0;

 

Mon Jan 28 19:28:04 2013  Critical (3)     Resetting the cable modem due to docsDevResetNow

 

Mon Jan 28 19:19:00 2013  Notice (6)       TLV-11 - unrecognized OID;CM-MAC=8c:04:ff:36:ef:e6;CMTS-MAC=00:01:5c:32:96:88;CM-QOS=1.1;CM-VER=3.0;

 

Mon Jan 28 19:17:56 2013  Critical (3)     Resetting the cable modem due to docsDevResetNow

 

Mon Jan 28 18:16:38 2013  Notice (6)       TLV-11 - unrecognized OID;CM-MAC=8c:04:ff:36:ef:e6;CMTS-MAC=00:01:5c:32:96:88;CM-QOS=1.1;CM-VER=3.0;

 

Mon Jan 28 18:14:33 2013  Notice (6)       TLV-11 - unrecognized OID;CM-MAC=8c:04:ff:36:ef:e6;CMTS-MAC=00:01:5c:32:96:88;CM-QOS=1.1;CM-VER=3.0;

 

Mon Jan 28 17:01:40 2013  Critical (3)     Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=8c:04:ff:36:ef:e6;CMTS-MAC=00:01:5c:32:96:88;CM-QOS=1.1;CM-VER=3.0;

 

Mon Jan 28 17:01:40 2013  Critical (3)     SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=8c:04:ff:36:ef:e6;CMTS-MAC=00:01:5c:32:96:88;CM-QOS=1.1;CM-VER=3.0;

 

Mon Jan 28 17:01:39 2013  Critical (3)     Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=8c:04:ff:36:ef:e6;CMTS-MAC=00:01:5c:32:96:88;CM-QOS=1.1;CM-VER=3.0;

 

 

 

 

Networking Expert
kevj
Posts: 4,813
Registered: ‎10-03-2003

Re: Holy Lag Spikes Batman

The downstream power is a bit too high, by the look of it...if it fluctuates upward, you are probably going to see service problems. Comcast may need to address that somehow, unless one of the connection experts has another suggestion....

 

 

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New Visitor
teresamrabon931
Posts: 3
Registered: ‎02-04-2013

Re: Holy Lag Spikes Batman

Thanks kevj,

 

Is that something I can adjust on my own? If not, what course of action should I take?

Cable Expert
i-am-nerdburg
Posts: 11,036
Registered: ‎06-27-2009

Re: Holy Lag Spikes Batman

Yeah your signal is a little "hot". Some modems don't tolerate that at all. You can try a 6dB attenuator (search eBay or http://www.techtoolsupply.com/ProductDetails.asp?ProductCode=FAM-6HR)

 

Also call Comcast and check:

 

• Upstream Signal to Noise Ratio (SNR): Above 30 is acceptable. Higher is better. 
• Upstream Receive Power: Ideally this number should fall within the -7dBmV and +7dBmV range.