Inconsistency in WMI Win32_NetworkAdapter class (AdapterTypeId property)

Question

So I am exploring a Win 2008 Server machine with WMI queries on the Win32_NetworkAdapter class. This class is documented here: http://msdn.microsoft.com/en-us/library/aa394216(VS.85).aspx

Here's what it says about the possible values of that property. There's also an AdapterType property that returns the same information, only in the form of a descriptive string. ("Ethernet 802.3", "Wireless" etc.)

 0 - Ethernet 802.3
 1 - Token Ring 802.5
 2 - Fiber Distributed Data Interface (FDDI)
 3 - Wide Area Network (WAN)
 4 - LocalTalk
 5 - Ethernet using DIX header format
 6 - ARCNET
 7 - ARCNET (878.2)
 8 - ATM
 9 - Wireless
10 - Infrared Wireless
11 - Bpc
12 - CoWan
13 - 1394 (FireWire)

Four things that are bugging me:

a) Where's PPP/Dialup? Where's loopback?
b) What the netherworld are "Bpc" and "Cowan?"
c) When I perform an actual query (from a C# app using System.Management), one of the interfaces returned has an AdapterTypeId of 15 and an AdapterType of "Tunnel." Why isn't that documented?
d) The aforementioned query doesn't return the loopback interface at all!

What am I not getting here?

Answer 1

Please post your code so troubleshooting can be done easily.