This has been an ongoing issue for quite some time at the business I work at: the cablemodem reboots intermittently (on average once a day) -- taking around 4 minutes to completely reboot. During that time, internet is down (of course) along with the phone lines attached to that cablemodem.
BACKGROUND:
The building we're in has a total of 4 businesses located inside of it (4 suites) -- all with internet access. All with their own droplines. None have this problem -- I checked by looking at their cablemodem status page and checking the cablemodem uptime.
When the cablemodem reboots, there is no error log entry for it around that time -- nothing at all unusual. No T3 or T4 timeouts. Correctables and Uncorrectables are totally normal. I can tell when the cablemodem reboots in three ways:
Our ISP (optimum) owns all the networking hardware before (and including) the router: drop line (obviously) -> 2-way splitter (indoors) -> two cablemodems (to support a total of 5 phone lines) -> router. After that, we own the hardware, but there's nothing unusual going on (a switch, cat6 cabling, desktop PCs).
I only have access to the logs/status page of one of the cablemodems -- the one with 1 phone line and internet. The other just has 4 phone lines and is not attached to the router -- which is why I don't have access to the logs -- it doesn't have an IP address on the network. All I can say for certain is that the other cablemodem doesn't reboot at the same time.
Going to 192.168.100.1 gives me the status page for the cablemodem that handles internet access for the building. Currently, it's an Arris TM1602AP2 -- but this is the 14th time (literally) that the cablemodem has been replaced by optimum techs for this issue. Other things that they tried:
a) replacing all hardware from the router to the dropline (including the drop line and the router itself)
b) reprovisioning the other cablemodem (that usually just handles 4 phone lines) to handle the internet as well
c) dropping our static IP address (it's not critical for us to have one, so we figured why not try that since the other businesses in the same building don't have one)
d) dropping bandwidth from around 200mbps to 100mbps because that's what the other businesses have.
e) 6db attenuator (aka a pad)
Now, I'm not a cable tech. I'm a programmer, and (of course) I end up doing a lot of IT work. While there may have also been problems with that hardware (router to dropline) in the past (there was a serious packet loss issue that was resolved with replacing the dropline), it seems to be a problem related to the balancing of the power levels -- our business in the building (there are 3 other business and they do not have this problem) and all of them have MUCH longer line runs than us.
Our business has the shortest run. All the other businesses have an additional 150 to 200 feet of cable before their cablemodem than us. It seems like the powerlevels are balanced in general for the whole building -- not for us, and we're getting screwed by that.
Powerlevels (averages, cold weather -- it's much worse the colder it gets):
Right now:
Without an attenuator / splitter:
Downstream: +18 dbmv (waayyy too high)
Upstream: 42 dbmv (great)
We do absolutely need the 2 way splitter though, so:
With splitter (but no attenuator):
Downstream: +15 dbmv (too high)
Upstream: 45 dbmv (great)
With 6db attenuator (what I'm using now and crossing my fingers hoping for the best):
Downstream: +9 dbmv (on the high side)
Upstream: 51 dbmv (starting to get high)
Using an attenuator, the above is the best we can do.
MY REAL QUESTION:
Would removing the attenuator, and instead add an extra 150 feet of cable to the dropline result in better downstream/upstream power level balance? Because that's really the ONLY difference between our suite in the building and the 3 other businesses there (we have a much shorter run than any of them).
THEIR powerlevels right now (NO attenuator, one 2-way splitter):
Downstream: +9 dbmv
Upstream: 42 dbmv
OUR powerlevels right now (NO attenuator, one 2-way splitter):
Downstream: +15 dbmv (too high)
Upstream: 45 dbmv (great)
The only difference at this point is their drop line length (+150 - 200 ft)!
EDIT 1: Changing ISPs isn't an option -- Verizon FIOS isn't offered in our area.
EDIT 2: Optimum wouldn't just give us an extra 150 feet of cable, but I could just buy it myself.
EDIT 3: I don't know what's going on at the dropline tap at all, and neither does optimum apparently. All businesses in our building have their own dropline running from the pole, though, so I'd imagine there's no tap... but there might be, but then the tap would have to be at the pole itself.
BACKGROUND:
The building we're in has a total of 4 businesses located inside of it (4 suites) -- all with internet access. All with their own droplines. None have this problem -- I checked by looking at their cablemodem status page and checking the cablemodem uptime.
When the cablemodem reboots, there is no error log entry for it around that time -- nothing at all unusual. No T3 or T4 timeouts. Correctables and Uncorrectables are totally normal. I can tell when the cablemodem reboots in three ways:
- experiencing it (although i'm usually not onsite when it happens, but sometimes I am)
- looking at the uptime shown in the cablemodem status webpage
- looking at the packetcable mta events for when the phone line, for example:
11/13/2019 3:08 | 16 | MTA TFTP: Successful |
11/13/2019 3:08 | 26 | MTA PROV: Successful! |
11/13/2019 3:08 | 3 | Voice Line State Change, Line Number = 1, Prev State = OOS, New State = IS |
Our ISP (optimum) owns all the networking hardware before (and including) the router: drop line (obviously) -> 2-way splitter (indoors) -> two cablemodems (to support a total of 5 phone lines) -> router. After that, we own the hardware, but there's nothing unusual going on (a switch, cat6 cabling, desktop PCs).
I only have access to the logs/status page of one of the cablemodems -- the one with 1 phone line and internet. The other just has 4 phone lines and is not attached to the router -- which is why I don't have access to the logs -- it doesn't have an IP address on the network. All I can say for certain is that the other cablemodem doesn't reboot at the same time.
Going to 192.168.100.1 gives me the status page for the cablemodem that handles internet access for the building. Currently, it's an Arris TM1602AP2 -- but this is the 14th time (literally) that the cablemodem has been replaced by optimum techs for this issue. Other things that they tried:
a) replacing all hardware from the router to the dropline (including the drop line and the router itself)
b) reprovisioning the other cablemodem (that usually just handles 4 phone lines) to handle the internet as well
c) dropping our static IP address (it's not critical for us to have one, so we figured why not try that since the other businesses in the same building don't have one)
d) dropping bandwidth from around 200mbps to 100mbps because that's what the other businesses have.
e) 6db attenuator (aka a pad)
Now, I'm not a cable tech. I'm a programmer, and (of course) I end up doing a lot of IT work. While there may have also been problems with that hardware (router to dropline) in the past (there was a serious packet loss issue that was resolved with replacing the dropline), it seems to be a problem related to the balancing of the power levels -- our business in the building (there are 3 other business and they do not have this problem) and all of them have MUCH longer line runs than us.
Our business has the shortest run. All the other businesses have an additional 150 to 200 feet of cable before their cablemodem than us. It seems like the powerlevels are balanced in general for the whole building -- not for us, and we're getting screwed by that.
Powerlevels (averages, cold weather -- it's much worse the colder it gets):
Right now:
Without an attenuator / splitter:
Downstream: +18 dbmv (waayyy too high)
Upstream: 42 dbmv (great)
We do absolutely need the 2 way splitter though, so:
With splitter (but no attenuator):
Downstream: +15 dbmv (too high)
Upstream: 45 dbmv (great)
With 6db attenuator (what I'm using now and crossing my fingers hoping for the best):
Downstream: +9 dbmv (on the high side)
Upstream: 51 dbmv (starting to get high)
Using an attenuator, the above is the best we can do.
MY REAL QUESTION:
Would removing the attenuator, and instead add an extra 150 feet of cable to the dropline result in better downstream/upstream power level balance? Because that's really the ONLY difference between our suite in the building and the 3 other businesses there (we have a much shorter run than any of them).
THEIR powerlevels right now (NO attenuator, one 2-way splitter):
Downstream: +9 dbmv
Upstream: 42 dbmv
OUR powerlevels right now (NO attenuator, one 2-way splitter):
Downstream: +15 dbmv (too high)
Upstream: 45 dbmv (great)
The only difference at this point is their drop line length (+150 - 200 ft)!
EDIT 1: Changing ISPs isn't an option -- Verizon FIOS isn't offered in our area.
EDIT 2: Optimum wouldn't just give us an extra 150 feet of cable, but I could just buy it myself.
EDIT 3: I don't know what's going on at the dropline tap at all, and neither does optimum apparently. All businesses in our building have their own dropline running from the pole, though, so I'd imagine there's no tap... but there might be, but then the tap would have to be at the pole itself.
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