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Re: Xfinity Speed slow with C7000 and R8500 Nighthawk

awitek
Aspirant

Xfinity Speed slow with C7000 and R8500 Nighthawk

My setup is a C7000 modem connected to a R8500 router, with the router setup as an AP.  I have Xfinity Blast! internet service at 150Mbps.  When running Xfinity speed test on a wired connection or through a wifi connection, the max speed is 90Mbps. The hardware has all current firmware.  I contacted Xfinity and they have the C7000 on my account.  They also said that they didn't have any issues on their end and if the speed was that slow they would have to send a technician out for a fee.  

 

Anyone else have this issue? Is there a solution to the slow speeds?  Thanks!

Model: C7000|Nighthawk - AC1900 WiFi Cable Modem Router
Message 1 of 9
TheEther
Guru

Re: Xfinity Speed slow with C7000 and R8500 Nighthawk

You didn't specify whether you are getting these results connected through the R8500 or the C7000.  You should isolate the bottleneck.  Check your cables.  A speed test of 90 Mbps could be an indication that one of your Ethernet connections is running at 100 Mbps instead of 1000 Mbps.

Message 2 of 9
awitek
Aspirant

Re: Xfinity Speed slow with C7000 and R8500 Nighthawk

So I did the following:

 

  1. Disconnected the R8500 from the network.
  2. Run speed test with the wired connection to the C7000.  90 Mbps result.
  3. Factory reset the C7000.  Speed test result of 175 Mbps result.
  4. Reconnected the R8500 to the network.  Speed test result of 90 Mbps.
  5. Factory reset the R8500.  Speed test result 175 Mbps.  

Now the speed is good.  Anyone know why the factory reset would need to be done?  Anyways, thanks to all that read/replied.

Message 3 of 9
TheEther
Guru

Re: Xfinity Speed slow with C7000 and R8500 Nighthawk

Did you, perhaps, have QoS enabled?  QoS is useful for prioritizing traffic on slower Internet connections.  It's not very useful high speed connections such as yours.

Message 4 of 9
awitek
Aspirant

Re: Xfinity Speed slow with C7000 and R8500 Nighthawk

Didn't have it enabled.

Message 5 of 9
awitek
Aspirant

Re: Xfinity Speed slow with C7000 and R8500 Nighthawk

Now after having no speed issues the last few days, I ran the speed test and got a 90 Mbps result again. I didn't make any changes to the modem or router, and confirmed no issues/outages with Xfinity.  I isolated the modem to find the bottleneck, but that returned a 90 Mpbs speed test result.  

 

Could this be a hardware problem? Anyone have any ideas?

Message 6 of 9
TheEther
Guru

Re: Xfinity Speed slow with C7000 and R8500 Nighthawk

Did you check your cables?

 

What features have you enabled on the C7000?  Traffic metering, site blocking, port forwarding, etc.?

 

Have you looked at the logs or the Cable Connection page on the C7000?

Message 7 of 9
awitek
Aspirant

Re: Xfinity Speed slow with C7000 and R8500 Nighthawk

I think the cables are fine.  I also swapped them out with different ones, and it didn't change anything.

 

Other than the wifi and login passwords, the C7000 and R8500 are set at factory defaults.

 

I think the information provided on the Cable Connection is ok, and i'm not sure what to make of the informtion provided in the logs. Copies of them are below.

 

The only "strange" item I found is that "Europe" is selected for the Region Selection found in the Wireless Setup.  I can't chnage it to anything else because the pull-down selection box is locked-out.  

 

Advanced -> Administration-> Log:

 

DescriptionCountLast OccurrenceTargetSource
[admin login] from source 192.168.0.141Tue Jul 26 17:44:00 20160.0.0.0:0192.168.0.14:0
[admin login failure] from source 192.168.0.141Tue Jul 26 17:43:54 20160.0.0.0:0192.168.0.14:0
[admin login] from source 192.168.0.141Tue Jul 26 17:35:22 20160.0.0.0:0192.168.0.14:0
[admin login failure] from source 192.168.0.141Tue Jul 26 17:35:14 20160.0.0.0:0192.168.0.14:0

 

 

Advanced -> Administration -> Event Log:

 

TimePriorityDescription
1970-1-1, 00:00:38Critical (3)SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=b0:7f:b9:5c:c3:58;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
1970-1-1, 00:00:42Critical (3)SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=b0:7f:b9:5c:c3:58;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
1970-1-1, 00:00:42Critical (3)SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-MAC=b0:7f:b9:5c:c3:58;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
1970-1-1, 00:00:42Critical (3)SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=b0:7f:b9:5c:c3:58;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
1970-1-1, 00:00:49Critical (3)No Ranging Response received - T3 time-out;CM-MAC=b0:7f:b9:5c:c3:58;CMTS-MAC=00:01:5c:86:9a:6c;CM-QOS=1.0;CM-VER=3.0;
2016-7-24, 06:37:48Critical (3)No Ranging Response received - T3 time-out;CM-MAC=b0:7f:b9:5c:c3:58;CMTS-MAC=00:01:5c:86:9a:6c;CM-QOS=1.0;CM-VER=3.0;
1970-1-1, 00:00:37Critical (3)SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-MAC=b0:7f:b9:5c:c3:58;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
1970-1-1, 00:00:42Critical (3)No Ranging Response received - T3 time-out;CM-MAC=b0:7f:b9:5c:c3:58;CMTS-MAC=00:01:5c:86:9a:6c;CM-QOS=1.0;CM-VER=3.0;
1970-1-1, 00:00:38Critical (3)SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-MAC=b0:7f:b9:5c:c3:58;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
1970-1-1, 00:00:41Notice (6)WiFi Interface [wl0] set to Channel 1 (Side-Band Channel:N/A) - Reason:INIT
1970-1-1, 00:00:41Notice (6)WiFi Interface [wl1] set to Channel 153 (Side-Band Channel:N/A) - Reason:INIT
1970-1-1, 00:00:45Critical (3)No Ranging Response received - T3 time-out;CM-MAC=b0:7f:b9:5c:c3:58;CMTS-MAC=00:01:5c:86:9a:6c;CM-QOS=1.0;CM-VER=3.0;
1970-1-1, 00:00:53Notice (6)Honoring MDD; IP provisioning mode = IPv6
2016-7-26, 10:39:05Warning (5)TEK Invalid - Invalid Key Sequence Number;CM-MAC=b0:7f:b9:5c:c3:58;CMTS-MAC=00:01:5c:86:9a:6c;CM-QOS=1.1;CM-VER=3.0;

 

 

Cable Connection:

 

Frequency start Value

This field below allows you to modify the frequency the cable modem start with its scan during initialization and registration. Enter the new start frequency and restart the cable modem for it to take effect.

Starting Frequency

 0

 

Startup Procedure

Procedure

Status

Comment

Acquire Downstream Channel

741000000 Hz

Locked

Connectivity State

OK

Operational

Boot State

OK

Operational

Security

Enabled

BPI+

IP Provisioning Mode

Honor MDD

honorMdd(4)

 

Downstream Bonded Channels

Channel

Lock Status

Modulation

Channel ID

Frequency

Power

SNR

Correctables

Uncorrectables

1

Locked

QAM256

19

741000000 Hz

-3.1 dBmV

37.8 dB

7

0

2

Locked

QAM256

1

633000000 Hz

-5.6 dBmV

36.9 dB

11

0

3

Locked

QAM256

2

639000000 Hz

-6 dBmV

36.6 dB

16

0

4

Locked

QAM256

3

645000000 Hz

-6.2 dBmV

36.6 dB

27

0

5

Locked

QAM256

4

651000000 Hz

-6.5 dBmV

36.4 dB

15

0

6

Locked

QAM256

5

657000000 Hz

-6.3 dBmV

36.5 dB

14

0

7

Locked

QAM256

6

663000000 Hz

-6 dBmV

36.7 dB

15

0

8

Locked

QAM256

7

669000000 Hz

-5.7 dBmV

36.9 dB

8

0

9

Locked

QAM256

8

675000000 Hz

-5.5 dBmV

36.4 dB

10

0

10

Locked

QAM256

9

681000000 Hz

-5.2 dBmV

37.1 dB

9

0

11

Locked

QAM256

10

687000000 Hz

-5 dBmV

37.2 dB

9

0

12

Locked

QAM256

11

693000000 Hz

-4.9 dBmV

37.3 dB

13

0

13

Locked

QAM256

12

699000000 Hz

-4.9 dBmV

37.2 dB

12

0

14

Locked

QAM256

13

705000000 Hz

-4.6 dBmV

37.4 dB

15

0

15

Locked

QAM256

14

711000000 Hz

-4.4 dBmV

37.5 dB

11

0

16

Locked

QAM256

15

717000000 Hz

-4.2 dBmV

37.5 dB

14

0

17

Locked

QAM256

16

723000000 Hz

-4.1 dBmV

38.6 dB

0

0

18

Locked

QAM256

17

729000000 Hz

-3.7 dBmV

39 dB

0

0

19

Locked

QAM256

18

735000000 Hz

-3.5 dBmV

38.9 dB

0

0

20

Locked

QAM256

20

747000000 Hz

-3.9 dBmV

38.6 dB

0

0

21

Not Locked

Unknown

0

0 Hz

0.0 dBmV

0.0 dB

0

0

22

Not Locked

Unknown

0

0 Hz

0.0 dBmV

0.0 dB

0

0

23

Not Locked

Unknown

0

0 Hz

0.0 dBmV

0.0 dB

0

0

24

Not Locked

Unknown

0

0 Hz

0.0 dBmV

0.0 dB

0

0

 

Upstream Bonded Channels

Channel

Lock Status

US Channel Type

Channel ID

Symbol Rate

Frequency

Power

1

Locked

ATDMA

17

5120 Ksym/sec

36400000 Hz

45.5 dBmV

2

Locked

ATDMA

18

5120 Ksym/sec

29500000 Hz

44.8 dBmV

3

Locked

ATDMA

19

5120 Ksym/sec

22600000 Hz

43.5 dBmV

4

Locked

ATDMA

20

5120 Ksym/sec

15700000 Hz

42.3 dBmV

5

Not Locked

Unknown

0

0 Ksym/sec

0 Hz

0.0 dBmV

6

Not Locked

Unknown

0

0 Ksym/sec

0 Hz

0.0 dBmV

7

Not Locked

Unknown

0

0 Ksym/sec

0 Hz

0.0 dBmV

8

Not Locked

Unknown

0

0 Ksym/sec

0 Hz

0.0 dBmV

 

Current System Time:Tue Jul 26 17:36:05 2016

 

Message 8 of 9
DarrenM
Sr. NETGEAR Moderator

Re: Xfinity Speed slow with C7000 and R8500 Nighthawk

Hello awetik 

 

I do see some T3 timeouts so there is some type of noise on your line do you happen to have a cable splitter hooked up to the modem if so try to remove it and go directly to the wall and test to see if that improves the speeds. If not you may want to ask your ISP to send a Tech out and check the lines to see if there is a issue.

 

http://volpefirm.com/docsis_timout_descriptions/

 

DarrenM

Message 9 of 9
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