Hi,
I'm looking for some advice based on my recent configurations with a CASA C2200 CMTS. I have two different types of cable modems that I am testing on this CMTS an Arris SBG6580-2 and an Arris SB6190. The 6190 cable modem goes online and when I connect CPE device behind it the device acquires IP via DHCP and I am able to get to the internet. However when I connect the 6580-2 cable modem this modem does not download the config file and it keeps looping in ranging state. Watching the cable modem on the CMTS I can see that it goes all the way to init(o) and then starts ranging over again. It never goes online. I also tested UBEE cable modem and a Netgear cable modem which has built in CPE interface with wifi router and they give the same issue. They never go online and just keeps looping in ranging state.
Any advice on this would be greatly appreciated.
Regards,
Moamar
It is hard to tell exactly from what you have described, but I suspect that the issue is extended upstream hi-power.
The Casa C2200 does not know about extended upstream transmit.
Arris/Motorola added the capability for extended upstream transmit and defaulted it to on.
Since the Casa CMTS does not understand the Extended Upstream Transmit TLV the modem is telling it to restart.
modems that use 1166 for their vendor ID (AKA Surfboards)
cmExtendedUsTxPowerCapable
1.3.6.1.4.1.1166.1.19.3.100.7.2
set it to false (2)
Enable/disable to report the extended upstream transmit power capability TLV 5.40 (used for post-registration).
If this object is set to true, the CM will report extended u/s transmit power capability in the REG-REQ-MP.
If false, the CM will report extended u/s transmit power capability in the REG-REQ-MP when the
CMTS's pre-registration upstream extended power (TLV16) is enabled.
The value of this MIB object only takes effect after a device reboot.
Here is the Arris equivalent
arrisCmDoc30SetupExtendedUpstreamTransmitPowerValue
1.3.6.1.4.1.4115.1.3.4.1.3.32
set it to 0 to disable
When enabled, extended upstream transmit power capabilities will be reported in REG-REQ-MP
message. Setting to 0 disables this functionality. Setting to nonzero controls what Pmax
the modem advertises in 0.25dB steps. The default value is hardware-specific.
It is not recommended to change from default values. Exceeding the capabilities of the upstream
amplifier may introduce distortions and spurs which may decrease SNR of this upstream channel and
adjacent upstream channels. Please refer to the Firmware Guide and take care when setting this value.
when in doubt, put both.
I don't have the proper oids for Netgear or UBEE but they should be able to be gathered easily.
Regardless of which OID is applicable it needs to be set in modem config file to be useful.
If that doesn't work let me know could be a couple other things, but that is most likely
Thank you for the feedback I will give it a try and let you know the results.
Hi kwesibrunee,
Many thanks for the advice man! It seems like the Extended Upstream Transmit TLV is the culprit here. To test before i made any changes to the mib for the docsis file, I went ahead and disabled on of the upstream channels from the CMTS and the modem went online with no issues. I am bonding 2 upstreams to this service group so I went ahead and removed one of them from the service group and also placed the channel in shutdown mode. After that the cable modem came online. I will now manipulate the docsis conf file to disable that feature from the modem. As Arris modems are the ones we will be using on this CMTS.
Thanks again, I really appreciate it!
Moamar