Pushing up to 16 VarBinds in packet can cause some devices to drop packet.

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node-snmp-native/lib/snmp.js

Lines 636 to 640 in 13b1428

	// Push up to 16 varbinds in the same message.
	// The number 16 isn't really that magical, it's just a nice round
	// number that usually seems to fit withing a single packet and gets
	// accepted by the switches I've tested it on.
	for (m = 0; m < 16 && c < options.oids.length; m++) {

I have run into a few networked devices (mostly resource-constrained, such as UPS network cards), which will just drop a packet which has has tried to shove up to 16 Var Binds in it, due to it being too large. By changing this value to 5 or 6, the device will accept it.

Excerpt from the SNMP Protocol Specification RFC1157 Page 16, Chapter 4:

An implementation of this protocol need not accept messages whose length exceeds 484 octets.

I will look into a way to determine the real-time size as the packet gets constructed to see if we can limit the size of the packet to 484 bytes.