NSIP(4) 						     Kernel Interfaces Manual							   NSIP(4)

NAME

       nsip - software network interface encapsulating ns packets in ip packets.

SYNOPSIS

       #include <netns/ns_if.h>

       Not currently supported under 2.11BSD

DESCRIPTION

       The nsip interface is a software mechanism which may be used to transmit 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 artificial 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.

3rd Berkeley Distribution					 January 27, 1996							   NSIP(4)