4.3BSD - /usr/man/cat4/ns.0

NS(4F)                                                                  NS(4F)


NAME
       ns - Xerox Network Systems(tm) protocol family

SYNOPSIS
       options NS
       options NSIP
       pseudo-device ns

DESCRIPTION
       The  NS  protocol  family is a collection of protocols layered atop the
       Internet Datagram Protocol (IDP) transport layer, and using  the  Xerox
       NS  address  formats.   The NS family provides 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 pack‐
       ets entering, (or with toggling kernel variable, additionally  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  <netns/ns.h>
       defines  the  NS  address as a structure containing unions (for quicker
       comparisons).

       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;
       };

       Sockets  may be created with an address of all zeroes to effect ‘‘wild‐
       card’’ matching on incoming messages.  The local port address specified
       in  a  bind(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) idp(4P), Error Protocol (avail‐
       able through IDP), and Sequenced Packet Protocol (SPP) spp(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 kernel 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),  getpro‐
       toent(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


4.3 Berkeley Distribution        July 30, 1985                          NS(4F)