eMTA issue, 2 upstream channels not bonded. | docsis.org

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eMTA issue, 2 upstream channels not bonded.

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krs123
eMTA issue, 2 upstream channels not bonded.

Below is eMTA Docsis info, modem have issues with upstream channels, two channels not bonded. What can cause this issue?
+----------------------------+-------------+------------+--------------+-----------+-----------+
| Downstream Bonded Channels | | | | | |
+----------------------------+-------------+------------+--------------+-----------+-----------+
| Channel | Lock Status | Modulation | Frequency | Power | SNR |
| 1 | Locked | QAM256 | 330000000 Hz | -1.5 dBmV | 38.0 dBmV |
| 2 | Locked | QAM256 | 338000000 Hz | -1.0 dBmV | 39.0 dBmV |
| 3 | Locked | QAM256 | 346000000 Hz | -1.2 dBmV | 39.1 dBmV |
| 4 | Locked | QAM256 | 354000000 Hz | -1.8 dBmV | 38.2 dBmV |
| 5 | Not Locked | Unknown | 0 Hz | 0.0 dBmV | 0.0 dBmV |
| 6 | Not Locked | Unknown | 0 Hz | 0.0 dBmV | 0.0 dBmV |
| 7 | Not Locked | Unknown | 0 Hz | 0.0 dBmV | 0.0 dBmV |
| 8 | Not Locked | Unknown | 0 Hz | 0.0 dBmV | 0.0 dBmV |
+----------------------------+-------------+------------+--------------+-----------+-----------+

+--------------+----------------+
| Correctables | Uncorrectables |
+--------------+----------------+
| 4560 | 457 |
+--------------+----------------+

+--------------------------+-------------+-----------------+---------------+-------------+-----------+
| Upstream Bonded Channels | | | | | |
+--------------------------+-------------+-----------------+---------------+-------------+-----------+
| Channel | Lock Status | US Channel Type | Symbol Rate | Frequency | Power |
| 1 | Locked | ATDMA | 5120 Ksym/sec | 50300000 Hz | 46.8 dBmV |
| 2 | Locked | ATDMA | 5120 Ksym/sec | 43900000 Hz | 46.8 dBmV |
| 3 | Not Locked | Unknown | 0 Ksym/sec | 0 Hz | 0.0 dBmV |
| 4 | Not Locked | Unknown | 0 Ksym/sec | 0 Hz | 0.0 dBmV |
+--------------------------+-------------+-----------------+---------------+-------------+-----------+

cmcaldas
levels, config

have you tried less attenuation on the upstream?
can you post the running config on the cmts? possible bonding issue there?
other 3.0 modem, non mta bonding on all upstream channels?

krs123
I can't get running config.

I have no running config from CMTS. These Ubee MTA are used as data modems (no telephony enabled). I checked status of other Ubee MTAs, some of them have this upstream bonding issue issue too, only 2 upstream channels are bonded(1,2). It seems, the issue mainly have ones where Upstream channels have higher power level (53.5 dBmV, 54.0 dBmV), whereas devices with less power level have all 4 channels bonded (28.0 dBmV - 49.3 dBmV) The other 3.0 modems(non mta) I checked have all upstream channels bonded. This issue is non-permanent or stable, today I checked this device and all 4 upstream channels are bonded. At the same time, the number of Correctables / Uncorrectables in Status page has significantly increased.
+--------------+----------------+
| Correctables | Uncorrectables |
+--------------+----------------+
| 304314 | 7657 |
+--------------+----------------+

wittmann
US-Bonding is related to Tx-Power level

Keep in mind that the upstream bonding capability is also depending to the current Tx-Power level of the cable modem.

Let's make a short example for a simple DOCSIS 3.0 environment with four upstream channel bonding without the feature of extended upstream power:

till < 52 dBmV: four channel bonding
greater as 52 dBmV but less as 55 dBmV: two channel bonding
greater as 55 dBmV: no upstream channel bonding

There are also some more points which you should be mentioned in case you're a operator of the CMTS but this is a other topic.

I advise you to visit www.cablelabs.com and looking out the great specifications there, which are available for everybody without any registration at all.

krs123
I noticed that sometimes even

I noticed that sometimes even only one upstream channel is locked, but modem still working and online.