not enabled, the status eld displays only the default letter "E", as displayed for BGP4 route 10.12.0.0/24. The letter "B" or "b" is missing
from the Status eld.
NOTE
The description of the status "b: NOT-INSTALLED-BEST" has changed. The status description for "b: NOT-INSTALLED-
BEST" is now: The routes received from the neighbor are the best BGP4 routes to their destinations, but were nonetheless not
installed in the IP route table due to the rib-route-limit option (or RTM route table size limit), and the always-propagate option
to allow the propagating of those best BGP routes.
NOTE
Trac loss on a BGP4 route occurs when a device is advertising preferred BGP4 routes not installed in the RTM as part of the
forwarding path.
Because the BGP4 route 10.12.0.0/24 is not considered as the best BGP4 route, the route is not advertised to other BGP4 neighbors.
device(config-bgp)# show ip bgp route 10.12.0.0/24
Number of BGP Routes matching display condition : 1
Status A:AGGREGATE B:BEST b:NOT-INSTALLED-BEST C:CONFED_EBGP D:DAMPED
E:EBGP H:HISTORY I:IBGP L:LOCAL M:MULTIPATH m:NOT-INSTALLED-MULTIPATH
S:SUPPRESSED F:FILTERED s:STALE
Prefix Next Hop MED LocPrf Weight Status
1 10.12.0.0/24 10.100.100.4 100 0 E
AS_PATH: 48 1994 65148 21948 6461 1239 4837 4808 17431 18245
Last update to IP routing table: 0h16m2s
No path is selected as BEST route
Syntax: show ip bgp route ip-address/
prex
After enabling the always-propagate command, the BGP4 route is now considered the best BGP4 route, even though the route is not
installed in the RTM. Because the rib-route-limit command was congured to allow for only 300,000 routes in the RTM some preferred
BGP4 routes are not installed in the RTM, and are not advertised to other BGP4 neighbors. By enabling the always-propagate
command, the device is now able to advertise those preferred BGP4 routes to other BGP4 neighbors. In the following example, the
Status eld displays "bE" indicating that the route is now considered the best BGP4 route for forwarding and will be advertised to other
BGP4 neighbors.
device(config-bgp)# show ip bgp route 10.12.0.0/24
Number of BGP Routes matching display condition : 1
Status A:AGGREGATE B:BEST b:NOT-INSTALLED-BEST C:CONFED_EBGP D:DAMPED
E:EBGP H:HISTORY I:IBGP L:LOCAL M:MULTIPATH m:NOT-INSTALLED-MULTIPATH
S:SUPPRESSED F:FILTERED s:STALE
Prefix Next Hop MED LocPrf Weight Status
1 10.12.0.0/24 10.100.100.4 100 0 bE
AS_PATH: 48 1994 65148 21948 6461 1239 4837 4808 17431 18245
Last update to IP routing table: 0h12m53s
Route is to be sent to 1 peers:
10.0.0.14(6)
For an explanation of the
elds displayed in the output of the show ip bgp route command, refer to Displaying information for a specic
route on page 455.
Specifying a maximum AS path length
You can use the maxas-limit in command to
congure a device running BGP4 to discard routes that exceed a specied AS path limit.
This limit can be congured globally, for peer groups, and for BGP neighbors.
Specifying a maximum AS path length
FastIron Ethernet Switch Layer 3 Routing
432 53-1003627-04
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