Example when recursive route lookups are enabled – Brocade Multi-Service IronWare Routing Configuration Guide (Supporting R05.6.00) User Manual
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Multi-Service IronWare Routing Configuration Guide
53-1003033-02
Enabling next-hop recursion
In this example, the device cannot reach 10.0.0.0/24, because the next-hop IP address for the
route is an IBGP route instead of an IGP route, and is considered unreachable by the device. The IP
route table entry for the next-hop gateway for the BGP4 route’s next-hop gateway (10.0.0.1/24) is
shown here.
Since the route to the next-hop gateway is a BGP4 route, and not an IGP route, it cannot be used to
reach 10.0.0.0/24. In this case, the device tries to use the default route, if present, to reach the
subnet that contains the BGP4 route next-hop gateway.
Example when recursive route lookups are enabled
When recursive next-hop lookups are enabled, the device continues to look up the next-hop
gateways along the route until the device finds an IGP route to the BGP4 route destination.
Brocade# show ip bgp route
Total number of BGP Routes: 5
Status A:AGGREGATE B:BEST b:NOT-INSTALLED-BEST C:CONFED_EBGP D:DAMPED
H:HISTORY I:IBGP L:LOCAL M:MULTIPATH S:SUPPRESSED
Prefix Next Hop
MED
LocPrf
Weight Status
1
0.0.0.0/0 10.1.0.2
0
100
0
BI
AS_PATH: 65001 4355 701 80
2
10.10.0.0/24 10.0.0.1 1
100
0
BI
AS_PATH: 65001 4355 1
3
10.40.0.0/24 10.1.0.2
0
100
0
BI
AS_PATH: 65001 4355 701 1 189
4
10.0.0.0/24 10.0.0.1
1
100
0
I
AS_PATH: 65001 4355 3356 7170 1455
5
10.25.0.0/24 10.157.24.1 1
100
0
I
AS_PATH: 65001 4355 701
Brocade# show ip route 10.0.0.1
Total number of IP routes: 37
Network Address Gateway Port Cost Type
10.0.0.0 10.0.0.1 1/1 1 B
Brocade# show ip route 10.0.0.0/24
Total number of IP routes: 37
Network Address Gateway Port Cost Type
0.0.0.0 10.0.0.202 1/1 1 S
Brocade# show ip bgp route
Total number of BGP Routes: 5
Status A:AGGREGATE B:BEST b:NOT-INSTALLED-BEST C:CONFED_EBGP D:DAMPED
H:HISTORY I:IBGP L:LOCAL M:MULTIPATH S:SUPPRESSED
Prefix Next Hop MED
LocPrf Weight Status
1 0.0.0.0/0 10.1.0.2 0 100 0 BI
AS_PATH: 65001 4355 701 80
2 10.10.0.0/24 10.0.0.1 1 100 0 BI
AS_PATH: 65001 4355 1
3 10.40.0.0/24 10.1.0.2 0 100 0 BI
AS_PATH: 65001 4355 701 1 189
4 10.0.0.0/24 10.0.0.1 1 100 0 BI
AS_PATH: 65001 4355 3356 7170 1455
5 10.25.0.0/24 10.157.24.1 1 100 0 I
AS_PATH: 65001 4355 701