-- 比较系统的描述
http://blog.sina.com.cn/s/blog_54837cf301011607.html
几个SNMP官方网站(搜索关键字：snmplibrary C#):
http://www.snmpsharpnet.com/?page_id=114
https://archive.codeplex.com/?p=sharpsnmplib
https://www.codeproject.com/Articles/12993/SNMP-library
http://www.dart.com/snmp-code-samples-examples.aspx