Possible enumeration values:
| Name | Value | Description | 
|---|---|---|
| Unknown | 
                     -1  | 
                |
| Unspecified | 
                     0  | 
                |
| Unix | 
                     1  | 
                |
| InterNetwork | 
                     2  | 
                |
| ImpLink | 
                     3  | 
                |
| Pup | 
                     4  | 
                |
| Chaos | 
                     5  | 
                |
| NS | 
                     6  | 
                |
| Ipx | 
                     6  | 
                |
| Iso | 
                     7  | 
                |
| Osi | 
                     7  | 
                |
| Ecma | 
                     8  | 
                |
| DataKit | 
                     9  | 
                |
| Ccitt | 
                     10  | 
                |
| Sna | 
                     11  | 
                |
| DecNet | 
                     12  | 
                |
| DataLink | 
                     13  | 
                |
| Lat | 
                     14  | 
                |
| HyperChannel | 
                     15  | 
                |
| AppleTalk | 
                     16  | 
                |
| NetBios | 
                     17  | 
                |
| VoiceView | 
                     18  | 
                |
| FireFox | 
                     19  | 
                |
| Banyan | 
                     21  | 
                |
| Atm | 
                     22  | 
                |
| InterNetworkV6 | 
                     23  | 
                |
| Cluster | 
                     24  | 
                |
| Ieee12844 | 
                     25  | 
                |
| Irda | 
                     26  | 
                |
| NetworkDesigners | 
                     28  | 
                |
| Max | 
                     29  | 
                |
| Packet | 
                     65536  | 
                |
| ControllerAreaNetwork | 
                     65537  |