From the doc:
I added to interfaces.xml ifHighSpeed and refreshed the SNMP cache for some interfaces so ifHighSpeed is populated, but link usage doesn't calculate correctly.As a final feature, if you add 'SET cacti_use_ifspeed 1' to either the link or node, or any item it inherits settings from (e.g. DEFAULT) then Weathermap will take the value of ifSpeed (or ifHighSpeed for 4G+ links) and use it in place of the value defined in the map config file - this allows you to do some basic dynamic configuration of Weathermap based on Cacti, which in turn should pick up changes from the network device.
interfaces.xml
<ifHighSpeed>
<name>HCSpeed</name>
<method>walk</method>
<source>value</source>
<direction>input</direction>
<oid>.1.3.6.1.2.1.31.1.1.1.15</oid>
</ifHighSpeed>
In my map I've enabled poller_output support and use_ifspeed.
SET rrd_use_poller_output 1
SET cacti_use_ifspeed 1
In weathermap I can print ifHighSpeed with {link:this:cacti_ifHighSpeed} but I'm not sure if weathermap uses this when setting cacti_use_ifspeed 1.
Thanks again for the awesome plugin.
sh0x