XNSROUTED(8)	    UNIX Programmer's Manual	     XNSROUTED(8)


NAME
     XNSrouted - NS Routing Information Protocol daemon

SYNOPSIS
     /sbin/XNSrouted [ -s ] [ -q ] [ -t ] [ logfile ]

DESCRIPTION
     XNSrouted is invoked at boot time to manage the Xerox NS
     routing tables.  The NS routing daemon uses the Xerox NS
     Routing Information Protocol in maintaining up to date ker-
     nel routing table entries.

     In normal operation XNSrouted listens for routing informa-
     tion packets.  If the host is connected to multiple NS net-
     works, it periodically supplies copies of its routing tables
     to any directly connected hosts and networks.

     When XNSrouted is started, it uses the SIOCGIFCONF ioctl to
     find those directly connected interfaces configured into the
     system and marked ``up'' (the software loopback interface is
     ignored).	If multiple interfaces are present, it is assumed
     the host will forward packets between networks.  XNSrouted
     then transmits a request packet on each interface (using a
     broadcast packet if the interface supports it) and enters a
     loop, listening for request and response packets from other
     hosts.

     When a request packet is received, XNSrouted formulates a
     reply based on the information maintained in its internal
     tables.  The response packet generated contains a list of
     known routes, each marked with a ``hop count'' metric (a
     count of 16, or greater, is considered ``infinite'').  The
     metric associated with each route returned provides a metric
     relative to the sender.

     Response packets received by XNSrouted are used to update
     the routing tables if one of the following conditions is
     satisfied:

     (1)  No routing table entry exists for the destination net-
	  work or host, and the metric indicates the destination
	  is ``reachable'' (i.e. the hop count is not infinite).

     (2)  The source host of the packet is the same as the router
	  in the existing routing table entry.	That is, updated
	  information is being received from the very internet-
	  work router through which packets for the destination
	  are being routed.

     (3)  The existing entry in the routing table has not been
	  updated for some time (defined to be 90 seconds) and
	  the route is at least as cost effective as the current


Printed 11/26/99	November 1, 1996			1


XNSROUTED(8)	    UNIX Programmer's Manual	     XNSROUTED(8)


	  route.

     (4)  The new route describes a shorter route to the destina-
	  tion than the one currently stored in the routing
	  tables; the metric of the new route is compared against
	  the one stored in the table to decide this.

     When an update is applied, XNSrouted records the change in
     its internal tables and generates a response packet to all
     directly connected hosts and networks.  Routed waits a short
     period of time (no more than 30 seconds) before modifying
     the kernel's routing tables to allow possible unstable
     situations to settle.

     In addition to processing incoming packets, XNSrouted also
     periodically checks the routing table entries.  If an entry
     has not been updated for 3 minutes, the entry's metric is
     set to infinity and marked for deletion.  Deletions are
     delayed an additional 60 seconds to insure the invalidation
     is propagated to other routers.

     Hosts acting as internetwork routers gratuitously supply
     their routing tables every 30 seconds to all directly con-
     nected hosts and networks.

     Supplying the -s option forces XNSrouted to supply routing
     information whether it is acting as an internetwork router
     or not.  The -q option is the opposite of the -s option.  If
     the -t option is specified, all packets sent or received are
     printed on the standard output.  In addition, XNSrouted will
     not divorce itself from the controlling terminal so that
     interrupts from the keyboard will kill the process.  Any
     other argument supplied is interpreted as the name of file
     in which XNSrouted's actions should be logged.  This log
     contains information about any changes to the routing tables
     and a history of recent messages sent and received which are
     related to the changed route.

SEE ALSO
     ``Internet Transport Protocols'', XSIS 028112, Xerox System
     Integration Standard.
     idp(4P)


Printed 11/26/99	November 1, 1996			2
 
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