5120 Ethernet Port Admin Up / Operationally Down? | docsis.org

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5120 Ethernet Port Admin Up / Operationally Down?

Just bought a bunch of used SB5120's and over half of them that I've provisioned appear to have toasted ethernet ports -- OR are intentionally in an "operationally down" state for some reason. My SNMP management setup doesn't provide a "set" to change the state to "up" and I'm wondering if there even is such a MIB -- or if the ports are indeed just toasted. Seems like quite a coincidence otherwise and the modems were
cleaned and screened (supposedly) and nicely re-packaged from a reputable reseller I use quite often who'll make good on any defective units.

Just wondering if I'm missing something obvious that could bring up those interfaces before I contact the seller to report "a problem".

Still learning the whole DOCSIS animal and running across new challenges every day.

But if it weren'r fun...

TIA as usual for any tips, tricks, or info.

Poge

Just thought of a possibility that I have seen in the past.....

if you look at the ethernet port on the back of the affected modems, check to see if the pins are not bent in, sometimes if someone puts an ethernet cable with the end not all the way crimped it stretches out the pins in the ethernet connector so when you put a normal connector in the pins do not make contact.

It did cross my mind, but after checking a couple and 10 out of the first 20 were bad, I figured it had to be something else like a firmware issue, a setting, or just bad ports. Near as I can figure it is the latter since I can find no way to change the operational status of the port except connecting it to a good link via a good jumper in an administratively "up" state, thereby creating an "operationally up" state -- in other words, simply an active link.

So what usually causes ethernet port failures on these things? Experience indicates power spikes and thunderstorm static discharge kill legacy modem ethernet ports. Same with DOCSIS?

Poge

Hi Poge
know you know better, but just a thought. try a modem file that disables the enet port and then another file to enable the port. the firmware on the modem wouldn't disable it unless it's a special build that wouldn't be in the field to begin with. what version firmware are they running and is it the same for the modems that have admin down?

Carl

Thanks for the idea, Carl.

After digging through the MIBs available in my SNMPc management app, I think I found the solution doing something similar, but by just toggling the ethernet admin status down and back up, then forcing operational status to up and doing a "set all". Doing so with at least one of these problem modems resulted in a good ethernet link that was previously non-functional. Seems to be the only way to see and set the "up" option on the operational side. Pain in the ass, but better than having to return around 100 5120's and THEN finding out they were actually ok, but just in some really weird state.

If it weren't fun!

Poge