The returned AP sn whitelist list when query AP sn whitelist in
batch. Two adjacent sn whitelist in the list are divided by '?'.
For example, if the start number is 10, and the query number is
50, then the host will find 50 valid sn whitelists from the 11th
valid sn whitelist.(Assume there are 100 sn whitelists in host.)
And each time the SNMP agent can get 128 sn whitelist at most.