4.3BSD-Reno/share/man/cat4/nsip.0

NSIP(4)                       1990			  NSIP(4)



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

SSYYNNOOPPSSIISS
     ooppttiioonnss NNSSIIPP
     ##iinncclluuddee <<nneettnnss//nnss__iiff..hh>>

DDEESSCCRRIIPPTTIIOONN
     The _n_s_i_p 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 inter-
     face 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 follow-
     ing 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;
     };


DDIIAAGGNNOOSSTTIICCSS
     nnssiipp%%dd:: ccaann''tt hhaannddllee aaff%%dd.  The interface was handed a mes-
     sage with addresses formatted in an unsuitable address fam-
     ily; the packet was dropped.

SSEEEE AALLSSOO
     intro(4), ns(4)

BBUUGGSS
     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 eenn device, and to
     allow passing XNS packets through an Arpanet-Milnet gateway,
     to facilitate testing between some co-operating universi-
     ties.



Printed 7/27/90               June				1