Hi,
we are using Arris C3 CMTS and have found out that with Thomson and Motorola CMs it happens that after they have uptime of litlle more than a day, they are starting to allow data transfers more than 30 MBit in downlink (speed limit in config file is set to 10240000 in downstream and 1024000 in upstream).
In the meantime modem doesn't download the configuration file so I have no idea why it should change its' working parameters. It successfully renews IP address and everything else is working normally. We are experiencing this on only one C3 CMTS. Even afer it starts speeding, after snmpwalk'ing the modem, we get:
SNMPv2-SMI::transmission.127.7.1.2.2.6.2.5625.1 = Gauge32: 1024000
SNMPv2-SMI::transmission.127.7.1.2.2.6.2.5625.2 = Gauge32: 1024000
SNMPv2-SMI::transmission.127.7.1.2.2.6.2.5625.3 = Gauge32: 1024000
SNMPv2-SMI::transmission.127.7.1.2.2.6.2.37994.1 = Gauge32: 10240000
SNMPv2-SMI::transmission.127.7.1.2.2.6.2.37994.2 = Gauge32: 10240000
SNMPv2-SMI::transmission.127.7.1.2.2.6.2.37994.3 = Gauge32: 10240000
It's the same as it was when modem successufully downloaded the configuration file about 2 days ago.
The issue doesn't happen on Arris modems ...
It is very strange and possibly dangerous because of using too much bandwidth - that's why there is MaxRateSustained ...
Configuration file:
Main
{
DownstreamFrequency 450000000;
NetworkAccess 1;
MaxCPE 1;
UsServiceFlow
{
MaxConcatenatedBurst 3236;
UsServiceFlowRef 1;
QosParamSetType 7;
MaxRateSustained 1024000;
MaxTrafficBurst 3236;
}
DsServiceFlow
{
DsServiceFlowRef 2;
QosParamSetType 7;
MaxRateSustained 10240000;
MaxTrafficBurst 3236;
}
GlobalPrivacyEnable 1;
}
This is really very strange issue which can have an enormous effect on the network function and my question is: how can I solve it? did it happen to anyone already? If you need any more information, please note it.
TIA
Sorry I don't know enough on the C3, but know that on the Motorola cmts's, you need to have rate limit configured on the downstream and upstream. otherwise modems would use whatever bandwidth is available. as seen in your post.
Can you or someone else in the group confirm if that's configurable on the C3 cmts?
~Carl
After more than 30 hours now also Arris cable modem downloads data even about 1 MBit faster than Thomson and Motorola ... and CMTS configuration seems to be the same as on other C3 CMTS's... It's amazing to see that ...
Any ideas? I can't believe we are the first to achieve this ...
TIA
The strange thing is that the speed limitation actually works on this same device for about 30 hours ... Then it starts speeding up as much as possible and it doesn't download any configure file etc. from TFTP so no configuration changes should occur. After rebooting the cycle repeats ... Works as it should for about 30 hours and then again speedup ...
BR