cancel
Showing results for 
Search instead for 
Did you mean: 

MTU ?

derek765
Dialled in

I've generally had a decent connection and good speeds over the last two or three weeks.
There have been a couple of occasions where the Hub seemed to reboot and was offline for some minutes.
The first of these was early one morning so I thought it may be a firmware update.
This morning all was fine until 9:00, and it's been wobbly ever since. No known issues in my area  but I keep losing connection. 
Did notice MTU was is to 1928, when the valid range appears to be 1280-1500
The network log is pasted below (timestamps are 2 hours out)

01-08-2023 11:43:57noticeCM-STATUS message sent. Event Type Code: 24; Chan ID: 159; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: 3.;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
01-08-2023 11:42:00warningDBC-REQ Mismatch Between Calculated Value for P1.6hi Compared to CCAP Provided Value;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
01-08-2023 11:42:00noticeUS profile assignment change. US Chan ID: 6; Previous Profile: 11 13; New Profile: 12 13.;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
01-08-2023 11:41:47noticeCM-STATUS message sent. Event Type Code: 16; Chan ID: 159; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: 3.;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
01-08-2023 11:40:56noticeUS profile assignment change. US Chan ID: 6; Previous Profile: 13; New Profile: 11 13.;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
01-08-2023 11:40:56warningDBC-REQ Mismatch Between Calculated Value for P1.6hi Compared to CCAP Provided Value;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
01-08-2023 11:40:52noticeREGISTRATION COMPLETE - Waiting for Operational status
01-08-2023 11:40:46warningRNG-RSP CCAP Commanded Power in Excess of 6 dB Below the Value Corresponding to the Top of the DRW;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
01-08-2023 11:40:46warningDynamic Range Window violation
01-08-2023 11:40:46warningDynamic Range Window violation
01-08-2023 11:40:46warningRNG-RSP CCAP Commanded Power in Excess of 6 dB Below the Value Corresponding to the Top of the DRW;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
01-08-2023 11:40:46warningDynamic Range Window violation
01-08-2023 11:40:46warningRNG-RSP CCAP Commanded Power in Excess of 6 dB Below the Value Corresponding to the Top of the DRW;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
01-08-2023 11:40:46warningDynamic Range Window violation
01-08-2023 11:40:46warningRNG-RSP CCAP Commanded Power in Excess of 6 dB Below the Value Corresponding to the Top of the DRW;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
01-08-2023 11:40:46warningDynamic Range Window violation
01-08-2023 11:40:46warningREG-RSP-MP Mismatch Between Calculated Value for P1.6hi Compared to CCAP Provided Value;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
01-08-2023 11:40:46warningRNG-RSP CCAP Commanded Power in Excess of 6 dB Below the Value Corresponding to the Top of the DRW;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
01-08-2023 11:40:46warningRNG-RSP CCAP Commanded Power Exceeds Value Corresponding to the Top of the DRW;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
01-08-2023 11:40:46warningDynamic Range Window violation
01-08-2023 11:40:41noticeDS profile assignment change. DS Chan ID: 32; Previous Profile: ; New Profile: 1 2 3.;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
01-08-2023 11:40:29warningDHCP WARNING - Non-critical field invalid in response ;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
01-08-2023 11:40:27noticeHonoring MDD; IP provisioning mode = IPv4
01-08-2023 11:40:09criticalSYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
01-08-2023 11:40:09criticalReceived Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
01-08-2023 11:40:06criticalNo Maintenance Broadcasts for Ranging opportunities received - T2 time-out;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
01-08-2023 11:40:06criticalSYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
01-08-2023 11:39:54criticalNo Maintenance Broadcasts for Ranging opportunities received - T2 time-out;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
01-08-2023 11:39:54criticalSYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
01-08-2023 11:39:52noticeCM-STATUS message sent. Event Type Code: 4; Chan ID: 25; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: N/A.;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
01-08-2023 11:39:52criticalSYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
01-08-2023 11:39:52noticeCM-STATUS message sent. Event Type Code: 5; Chan ID: 25; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: N/A.;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
1 ACCEPTED SOLUTION

Accepted Solutions

Hi @derek765,

Our systems are identifying a short-term network issue that could cause degradation or an intermittent service.

We believe it will only be a short-term issue and it will be fixed very soon. However, in the meantime, could you please check that the coax cables are connected securely to the Virgin Media equipment, any splitters (standard and powered) and to the wall socket?

Regards,
Daniel

See where this Helpful Answer was posted

11 REPLIES 11

Client62
Hero

Check for issues in your street via : 0800 561 0061 - as ever, someone has to be the first to report a fault.

The info from the Upstream / Downstream tabs is a good place to look for hints of connection issues.

MTU is 1500 on our Hub which the setting the Hub arrived with.

Daniel_Et
Forum Team
Forum Team

Hi @derek765, thank you for your post.

We're sorry to hear about the problems you've been having 😔

We'd certainly suggest following the advice provided by @Client62 in the first instance.

If there aren't any issues on your street, advice on how to fix internet problems can be found here

Are you experiencing the same problems on devices connected via WiFi and ethernet cable?

Please pop back to us at your earliest convenience.

Regards,
Daniel

It's the router that's rebooting, so wireless or wired is irrelevant 🙂

Hi @derek765, thank you for your response.

Have you tried following the other advice provided? If so, has it shed any light on the cause of the problem?

Regards,
Daniel 

The router hasn't rebooted since, although I'm still seeing warnings in the log. While it's working, I don't have the time to sit on a telephone call !

Hi @derek765,

Our systems are identifying a short-term network issue that could cause degradation or an intermittent service.

We believe it will only be a short-term issue and it will be fixed very soon. However, in the meantime, could you please check that the coax cables are connected securely to the Virgin Media equipment, any splitters (standard and powered) and to the wall socket?

Regards,
Daniel

derek765
Dialled in

Cables etc. checked and all ok.
I updated MTU to 1500 yesterday and saved - its now back to 1978.
Entries in the log consistently up until around 00:10 (depending on the _actual_ time - now seem to have stopped. Perhaps something happened to fix overnight, or perhaps it's waiting to recur !

Hi @derek765, that's good to hear 😀

Please continue to monitor the situation and if any problems reoccur, don't hesitate to contact us.

Regards,
Daniel

legacy1
Alessandro Volta

Use modem mode get a router with 1Gb ports that will use the correct MTU

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