Hi
We have a monitoring of the upstream snr in our cisco cmts
we read the mib
1.3.6.1.2.1.10.127.1.1.4.1.5
we notice that the max value read is 36.1
so if a return has a better snr like 39 then the reading will still be 36.1
is it normal ?
is there another mib we could use that doesn't have that limit
For our 10k's the max value is around 36
Whereas cBR8 the max value is around 40
I assume its just a different measurement algorithm
Isnt the MIB just reporting the SNR (not CNR) value seen here? :
show controller cable 5/0/0 up 0 | incl NR
SNR MIB for upstream have no real standard.
This SNMP object is no more available in DOCSIS 3 MIB.
CMTS providers may use a CNR/SNR/MER or whatever value in DOCSIS MIB.
If you change CMTS manufacturer or type you may find several dB of difference with the same signal.
To work on accurate values you should work with SNR/MER at modem level:
.1.3.6.1.4.1.4491.2.1.20.1.4.1.4
Upstream "SNR" is just good enough for 5 minutes graphs compare to FEC and traffic graphs like everyone.
Hi
Just a follow up
upstream SNR reading are over 36 when using a MC3G60 card
the reading limit applies to MC20x20 cards