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

NSIP(4)                                                                NSIP(4)


NAME
       nsip  - software network interface encapsulating ns packets in ip pack‐
       ets.

SYNOPSIS
       options NSIP
       #include <netns/ns_if.h>

DESCRIPTION
       The nsip interface is a software mechanism which may be used to  trans‐
       mit  Xerox NS(tm) packets through otherwise uncooperative networks.  It
       functions by prepending an  IP  header,  and  resubmitting  the  packet
       through the unix IP machinery.

       The  super-user can advise the operating system of a willing partner by
       naming an IP address to be associated with an NS  address.   Presently,
       only specific hosts pairs are allowed, and for each host pair, an arti‐
       ficial point-to-point interface is constructed.  At some  future  date,
       IP  broadcast  addresses  or  hosts  may  be paired with NS networks or
       hosts.

       Specifically, a socket option of SO_NSIP_ROUTE is set on  a  socket  of
       family AF_NS, type SOCK_DGRAM, passing the following structure:

       struct nsip_req {
            struct sockaddr rq_ns;   /* must be ns format destination */
            struct sockaddr rq_ip;   /* must be ip format gateway */
            short rq_flags;
       };


DIAGNOSTICS
       nsip%d:  can’’t  handle  af%d.   The interface was handed a message with
       addresses formatted in an unsuitable address  family;  the  packet  was
       dropped.

SEE ALSO
       intro(4N), ns(4F)

BUGS
       It  is  absurd to have a separate pseudo-device for each pt-to-pt link.
       There is no way to change the IP address for an NS host  once  the  the
       encapsulation  interface  is set up.  The request should honor flags of
       RTF_GATEWAY to indicate remote networks,  and  the  absence  of  RTF_UP
       should be a clue to remove that partner.  This was intended to postpone
       the necessity of rewriting reverse ARP for the en device, and to  allow
       passing  XNS  packets  through an Arpanet-Milnet gateway, to facilitate
       testing between some co-operating universities.


4.3 Berkeley Distribution        July 30, 1985                         NSIP(4)