Docsis 3 SNR question | docsis.org

You are here

Docsis 3 SNR question

13 posts / 0 new
Last post
szpal
Docsis 3 SNR question

Hi,

Maybe someone can help:
Which SNMP OID can i use, when i would read the Docsis 3.0-s cm's US SNR's?
At Docsis 2.0 cm, the oid is docsIfCmtsCmStatusSignalNoise (1.3.6.1.2.1.10.127.1.3.3.1.13)
but at Docsis 3.0 cm this not work.
May be that there is no other solution, than 'show cable modem phy' cmts command output?
Thank you.

kwesibrunee
look here

look here

Object docsIf3CmtsCmUsStatusSignalNoise
OID 1.3.6.1.4.1.4491.2.1.20.1.4.1.4

fvargaspiedra
Do you know if...

Hi! I was wondering if you also know if there is an OID to get the descriptions (those that you write in each US interface) from US interfaces (Cisco UBR)

fvargaspiedra
ifAlias

Hi... I have already found my own question... It was easy when I realized one should look for "alias" instead of "interface description".

This is what I was talking about:

1.3.6.1.2.1.31.1.1.1.18
ifAlias

Thanks!

szpal
Snmpwalk or telnet?

Thank you kwesibrunee, first i think that oid is valid only in cisco world, but now i can see, that is cmts independent.
As i previously stated, (in this example) it is possible use cmts telnet command, that get the SNR values. (show cable modem phy)
However, as i see it the snmpwalk method is significantly slower than the telnet command method..
What do you think about?

husamaga
Do you need to read the SNR

Do you need to read the SNR for every modem? or for all modems together? (Upstream SNR)
I think the snr upstream for modems is the same, but the snr for upstream is diferent.

because i have 2 CMTS's and read the same informations from all modems docsis 2.0 & 3.0

OID for US SNR: enterprises.9.9.114.1.3.1.1

szpal
I read every modem

Yes, now i read every modems for their US SNR, ... but wait.... maybe it is unnecessary? Hmmm..
So you say that sufficient read the SNR for every upstream channel, and then assigned to the appropriate modems which are
of that upstream channel?

kwesibrunee
OID is short for Object

OID is short for Object IDentifier and refers to the 1.3.6. string.

That particular OID is not CMTS specific but rather Docsis 3 Specific any CMTS that is docsis 3 compliant, should support that OID for docsis 3 modems registered to it, for docsis 1.x and 2.x modems you may still need to use the old OID you already knew about.

husamaga
You will read the upstream

You will read the upstream SNR for all modems together. then if you get the SNR under 18 you will know that you have a problem on your network. i make US SNR for all modems together, and getting the all other paramters for each modem.
Also you can read the errors on that upstream and get a completed US monitoring.

eddie303
This OID gives 0

Hello,

does anyone else experience that docsIf3CmtsCmUsStatusSignalNoise returns 0 for every secondary logical channel? We're experiencing it on a Motorola BSR64000. Is there any workaround?

Thanks!

DocsisAdmin
Only on LC in use

BSRs have two logical channels for every physical upstream channel. It's normal for almost all cable operators to run only the first logical channel, thus when you do a 'show cable modem' you'll see that all the upstreams with modems registered end with /0 (or LC0). My guess is that your second logical channels are not configured as well, so the 0 SNR is expected and not indicative of problem.

eddie303
They are configured

The logical channels are configured and when issuing show cable modem. verbose the logical channel snr's are shown, however when queried over SNMP they return 0...

DocsisAdmin
That sounds like a weird bug.

That sounds like a weird bug. If you have modems that report registration on LC0 and LC1 both, then both *should* produce SNR values. However, I don't see many operators using LC1 so 0 is the value I usually see.

Log in or register to post comments