Hello. I need to convert an SFP DDM signal from mW to dBm. This requires the following formula:
10*log10(mW)=dBm
A simple comparison using if works, but puts a load on the switch, and works intermittently if used for all ports.
Maybe someone solved a similar problem?
I haven’t, but there is no log function AFAIK.
Another idea, not simple… but you can create an array with the dBm values inside, then use use array_element with the mW (or some multiple of mW) to fetch the pre-converted dBm value. Essentially a lookup table, using array()/array_element()functions.
e.g.
mW to dBm conversion table
Power (mW) Power (dBm)
0+ mW -∞ dBm
0.01 mW -20 dBm
0.1 mW -10 dBm
1 mW 0 dBm
2 mW 3.0103 dBm
3 mW 4.7712 dBm
4 mW 6.0206 dBm
5 mW 6.9897 dBm
6 mW 7.7815 dBm
7 mW 8.4510 dBm
8 mW 9.0309 dBm
9 mW 9.5424 dBm
10 mW 10 dBm
100 mW 20 dBm
1000 mW 30 dBm
10000 mW 40 dBm
100000 mW 50 dBm
1000000 mW 60 dBm
10000000 mW 70 dBm
100000000 mW 80 dBm
1000000000 mW 90 dBm
10000000000 mW 100 dBm
I decided to do it a little differently. With Raspberry (Orange Pi).
If I use it as a probe, everything is ok, no problems. But if I add it to the link label, Dude sends 324 requests/port per each update!!!.
?!?!?!
I have 1 switch x8 ports and 5 switches x24 ports.
Link label code:
[snmp_wireless_link_info()]Rx: [Interface.InBitRate][snmp_wireless_link_rx_rate()]
Tx: [Interface.OutBitRate][snmp_wireless_link_tx_rate()]
[if(string_find(device_property("FirstAddress"),"192.168.3.235")=0,sfp_ddm_link_rx_rate(),"")]
sfp_ddm_link_rx_rate() code:
if(
string_find(link_index(),"49153")=0,
if(
string_size(oid(concatenate("1.3.6.1.4.1.11863.6.96.1.7.1.1.6.","[Interface.Index]"), 300, 600))>4,
oid("1.3.6.1.4.1.8072.1.3.2.4.1.2.4.116.119.109.49.1",5,300,"192.168.3.233"),
""),
"")
Update interval is set for 5 sec.
And if I add code for all ports and switches, Dude sends 500,000 requests per minute…