HP-UX Reference (11i v1 00/12) - 4 File Formats (vol 8)

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STANDARD Printed by: Nora Chuang [nchuang] STANDARD
/build/1111/BRICK/man4/!!!intro.4
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g
gated.conf(4) gated.conf(4)
interface interface_list
Specifies the parameters that apply to physical interfaces. Note a slight difference in convention
from the rest of GateD, interface specifies just physical interfaces (such as le0, ef0 and en1).
The Router Discovery Client has no parameters that apply only to interface addresses.
enable Specifies that Router Discovery should be performed on the specified
interface(s). This is the default.
disable Specifies that Router Discovery should not be performed on the specified
interface(s).
broadcast Specifies that Router Solicitations should be broadcast on the specified
interface(s). This is the default if IP multicast support is not available on this
host or interface.
multicast Specifies that Router Solicitations should be multicast on the specified
interface(s). If IP multicast is not available on this host and interface, no soli-
citation will be performed. The default is to multicast Router Solicitations if
the host and interface support it. Otherwise Router Solicitations are broad-
cast.
quiet Specifies that no Router Solicitations will be sent on this interface, even
though Router Discovery will be performed.
solicit Specifies that initial Router Solicitations will be sent on this interface. This is
the default.
Tracing options
The Router Discovery Client and Server support the state trace flag which traces various protocol
occurrences.
state State transitions
The Router Discovery Client and Server do not directly support any packet tracing options, tracing of
router discovery packets is enabled via the ICMP Statement.
The Kernel Statement
While the kernel interface is not technically a routing protocol, it has many characteristics of one, and
GateD handles it similarly to one. The routes GateD chooses to install in the kernel forwarding table are
those that will actually be used by the kernel to forward packets.
The add, delete and change operations GateD must use to update the typical kernel forwarding table take a
non-trivial amount of time. This does not present a problem for older routing protocols (RIP, EGP), which
are not particularly time critical and do not easily handle very large numbers of routes anyway. The newer
routing protocols (OSPF, BGP) have stricter timing requirements and are often used to process many more
routes. The speed of the kernel interface becomes critical when these protocols are used.
To prevent GateD from locking up for significant periods of time installing large numbers of routes (up to a
minute or more has been observed on real networks), the processing of these routes is now done in batches.
The size of these batches may be controlled by the tuning parameters described below, but normally the
default parameters will provide the proper functionality.
During normal shutdown processing, GateD normally deletes all the routes it has installed in the kernel
forwarding table, except for those marked with retain. Optionally, GateD can leave all routes in the kernel
forwarding table by not deleting any routes. In this case changes will be made to insure that routes with a
retain indication are installed in the table. This is useful on systems with large numbers of routes as it
prevents the need to re-install the routes when GateD restarts. This can greatly reduce the time it takes to
recover from a restart.
Forwarding tables and Routing tables
The table in the kernel that controls the forwarding of packets is a forwarding table, also know in ISO
speak as a forwarding information base,orFIB. The table that GateD uses internally to store routing infor-
mation it learns from routing protocols is a routing table, known in ISO speak as a routing information
base,orRIB. The routing table is used to collect and store routes from various protocols. For each unique
combination of network and mask an active route is chosen, this route will be the one with the best (numer-
ically smallest) preference. All the active routes are installed in the kernel forwarding table. The entries in
this table are what the kernel actually uses to forward packets.
Section 4−−106 − 35 − HP-UX Release 11i: December 2000
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