


      ROUTED(1)                  (Bull-SPS9)                  ROUTED(1)



      NAME
           routed - network routing daemon

      SYNOPSIS
           /etc/routed [ -s ] [ -q ] [ -t ] [ logfile ]

      DESCRIPTION
           Routed is invoked at boot time to manage the network routing
           tables.  The routing daemon uses a variant of the Xerox NS
           Routing Information Protocol in maintaining up to date
           kernel routing table entries.

           In normal operation routed listens on udp(4P) socket 520
           (decimal) for routing information packets.  If the host is
           an internetwork router, it periodically supplies copies of
           its routing tables to any directly connected hosts and
           networks.

           When routed 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.  Routed 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, routed 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 routed are used to update the
           routing tables if one of the following conditions is
           satisfied:

           (1)  No routing table entry exists for the destination
                network 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
                internetwork router through which packets for the
                destination are being routed.

           (3)  The existing entry in the routing table has not been



      Page 1                                          (73 A2 02MT REV1)






      ROUTED(1)                  (Bull-SPS9)                  ROUTED(1)



                updated for some time (defined to be 90 seconds) and
                the route is at least as cost effective as the current
                route.

           (4)  The new route describes a shorter route to the
                destination 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, routed 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, routed 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 throughout the internet.

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

           Supplying the -s option forces routed 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, routed 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 routed'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.

           In addition to the facilities described above, routed
           supports the notion of ``distant'' passive and active
           gateways.  When routed is started up, it reads the file
           /etc/gateways to find gateways which may not be identified
           using the SIOGIFCONF ioctl.  Gateways specified in this
           manner should be marked passive if they are not expected to
           exchange routing information, while gateways marked active
           should be willing to exchange routing information (i.e.
           they should have a routed process running on the machine).
           Passive gateways are maintained in the routing tables
           forever and information regarding their existence is
           included in any routing information transmitted.  Active



      Page 2                                          (73 A2 02MT REV1)






      ROUTED(1)                  (Bull-SPS9)                  ROUTED(1)



           gateways are treated equally to network interfaces.  Routing
           information is distributed to the gateway and if no routing
           information is received for a period of the time, the
           associated route is deleted.

           The /etc/gateways is comprised of a series of lines, each in
           the following format:

           < net | host > name1 gateway name2 metric value < passive | active >

           The net or host keyword indicates if the route is to a
           network or specific host.

           Name1 is the name of the destination network or host.  This
           may be a symbolic name located in /etc/networks or
           /etc/hosts, or an Internet address specified in ``dot''
           notation; see inet(3N).

           Name2 is the name or address of the gateway to which
           messages should be forwarded.

           Value is a metric indicating the hop count to the
           destination host or network.

           The keyword passive or active indicates if the gateway
           should be treated as passive or active (as described above).

      FILES
           /etc/gateways  for distant gateways

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

      BUGS
           The kernel's routing tables may not correspond to those of
           routed for short periods of time while processes utilizing
           existing routes exit; the only remedy for this is to place
           the routing process in the kernel.

           Routed should listen to intelligent interfaces, such as an
           IMP, and to error protocols, such as ICMP, to gather more
           information.











      Page 3                                          (73 A2 02MT REV1)



