IPX Family of Protocol Identifiers

The protocol parameter in socket and WSASocket is an identifier that establishes a network type and a method for identifying the various transport protocols that run on the network. Unlike IP, IPX does not use a single protocol value for selecting a transport stack. Since there is no network requirement to use a specific value for each transport protocol, we are free to assign them in a manner convenient for Winsock applications. We avoid values 0–255 in order to avoid collisions with the corresponding PF_INET protocol values.

NameValueSocket typesDescription
Reserved0-255 Reserved for PF_INET protocol values.
NSPROTO_IPX1000 - 1255SOCK_DGRAM SOCK_RAWDatagram service for IPX.
NSPROTO_SPX1256SOCK_STREAM SOCK_SEQPKTReliable packet exchange using fixed-sized packets.


Note  When NSPROTO_SPX is specified, the SPX II protocol is automatically utilized if both endpoints are capable of doing so.