NAME    [Toc]    [Back]

     ns - Xerox Network Systems(tm) protocol family

SYNOPSIS    [Toc]    [Back]

     option NS
     option NSIP
     pseudo-device ns [count]

DESCRIPTION    [Toc]    [Back]

     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 packets
     entering,  (or  with  toggling kernel variable, additionally
leaving) the
     local host.

ADDRESSING    [Toc]    [Back]

     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 {
                   u_char          sns_len;
                   u_char          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
     ``wildcard''  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
     superuser, providing a space of protected port numbers.

PROTOCOLS    [Toc]    [Back]

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

     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    [Toc]    [Back]

     byteorder(3),   gethostbyname(3),   getnetent(3),    getprotoent(3),
     getservent(3), ns(3), idp(4), netintro(4), nsip(4), spp(4)

     Internet  Transport  Protocols,  Xerox  Corporation document
XSIS, 028112.

     An Advanced 4.3 BSD Interprocess Communication Tutorial.

HISTORY    [Toc]    [Back]

     The ns protocol family appeared in 4.3BSD.

OpenBSD     3.6                        November     30,      1993