NS(4F)		    UNIX Programmer's Manual		   NS(4F)



NAME
     ns - Xerox Network Systems(tm) protocol family

SYNOPSIS
     Not currently supported under 2.11BSD

DESCRIPTION
     The NS protocol family is a collection of protocols layered
     atop the _I_n_t_e_r_n_e_t _D_a_t_a_g_r_a_m _P_r_o_t_o_c_o_l (IDP) transport layer,
     and using the Xerox NS address formats.  The NS family pro-
     vides protocol support for the SOCK_STREAM, SOCK_DGRAM,
     SOCK_SEQPACKET, and SOCK_RAW socket types; the SOCK_RAW
     interface is a debugging tool, allowing you to trace all
     packets entering, (or with toggling kernel variable, addi-
     tionally leaving) the local host.

ADDRESSING
     NS addresses are 12 byte quantities, consisting of a 4 byte
     Network number, a 6 byte Host number and a 2 byte port
     number, all stored in network standard format.  (on the VAX
     these are word and byte reversed; on the Sun they are not
     reversed).  The include file <_n_e_t_n_s/_n_s._h> defines the NS
     address as a structure containing unions (for quicker com-
     parisons).

     Sockets in the Internet protocol family use the following
     addressing structure:

     struct sockaddr_ns {
	  short          sns_family;
	  struct ns_addr sns_addr;
	  char	    sns_zero[2];
     };

     where an ns_addr is composed as follows:

     union ns_host {
	  u_char	 c_host[6];
	  u_short	 s_host[3];
     };

     union ns_net {
	  u_char	 c_net[4];
	  u_short	 s_net[2];
     };

     struct ns_addr {
	  union ns_net	 x_net;
	  union ns_host  x_host;
	  u_short   x_port;
     };




Printed 11/26/99	January 27, 1996			1






NS(4F)		    UNIX Programmer's Manual		   NS(4F)



     Sockets may be created with an address of all zeroes to
     effect ``wildcard'' matching on incoming messages.  The
     local port address specified in a _b_i_n_d(2) call is restricted
     to be greater than NSPORT_RESERVED (=3000, in <netns/ns.h>)
     unless the creating process is running as the super-user,
     providing a space of protected port numbers.

PROTOCOLS
     The NS protocol family supported by the operating system is
     comprised of the Internet Datagram Protocol (IDP) _i_d_p(4P),
     Error Protocol (available through IDP), and Sequenced Packet
     Protocol (SPP) _s_p_p(4P).

     SPP is used to support the SOCK_STREAM and SOCK_SEQPACKET
     abstraction, while IDP is used to support the SOCK_DGRAM
     abstraction.  The Error protocol is responded to by the ker-
     nel to handle and report errors in protocol processing; it
     is, however, only accessible to user programs through heroic
     actions.

SEE ALSO
     intro(3), byteorder(3N), gethostbyname(3N), getnetent(3N),
     getprotoent(3N), getservent(3N), ns(3N), intro(4N), spp(4P),
     idp(4P), nsip(4)
     Internet Transport Protocols, Xerox Corporation document
     XSIS-028112
     An Advanced 4.3BSD Interprocess Communication Tutorial




























Printed 11/26/99	January 27, 1996			2