3Com 8807 Command Reference Manual page 386

384 C 23: S R
HAPTER TATIC
C C
OUTE ONFIGURATION OMMANDS
Table 49 Description of the fields of the display ip routing-table acl verbose command
Field
Route state description:
ActiveU
Blackhole
Delete
Gateway
Hidden
Holddown
Int
State
NoAdvise
NotInstall
Reject
Retain
Static
Description
Valid unicast route. U stands for
unicast.
Blackhole route is similar to Reject
route, but it will not send the ICMP
unreachable message to the source end
The route is deleted
Indicates that the route is not directly
reachable
The route exists, but it is unavailable
temporarily for some reasons (e.g.,
configured policy or interface is Down).
Moreover, you do not wish to delete it.
Therefore, you need to hide it, so as to
restore it again later
Holddown is one kind of route
redistribution policy adopted by some
distance-vector (D-V) routing protocols
(e.g., RIP), through which these routing
protocols can avoid the flooding of
error routes and deliver the routing
unreachable message accurately. For
example, the RIP imports a certain
route every a period of time regardless
of whether the actually found routes
destined for the same destination
change. For more details, refer to the
specific routing protocols.
The route is discovered by interior
gateway protocol (IGP).
The routing protocol does not import
NoAdvise route when it imports routes
based on the policy.
The routing protocol generally selects
the route with the highest precedence
from its routing table, then places it in
its core routing table and imports it.
Although the NotInstall route cannot
be placed in the core routing table, it is
possibly that it is selected and
imported.
Unlike the normal routes, the Reject
route will discard the packets that
select it as their route, and the router
will send ICMP unreachable message to
the source end. Reject route is usually
used for the network test
When the routes from the core routing
table are deleted, the routes with the
Retain flag will not be deleted. Using
this function you can set the Retain flag
for some static routes, so that they can
exist in the core routing table.
The route with Static flag will not be
cleared from the routing table after you
save it and reboot the router.
Generally, the static route configured
manually in the router belongs to a
Static route.