Brocade Virtual ADX Switch and Router Guide (Supporting ADX v03.1.00) User Manual
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Brocade Virtual ADX Switch and Router Guide
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Enabling next-hop recursion
8
The first lookup results in an IBGP route, to network 10.0.0.0/24.
Since the route to 10.2.0.1/24 is not an IGP route, the device cannot reach the next hop through IP,
and so cannot use the BGP4 route. In this case, since recursive next-hop lookups are enabled, the
device next performs a lookup for the next-hop gateway to 10.2.0.1’s next-hop gateway, 10.0.0.1.
The next-hop IP address for 10.0.0.1 is not an IGP route, which means the BGP4 route destination
still cannot be reached through IP. The recursive next-hop lookup feature performs a lookup on the
next-hop gateway for 10.0.0.1
.
This lookup results in an IGP route that is a directly-connected route. As a result, the BGP4 route
destination is now reachable through IGP, which means the BGP4 route can be added to the IP
route table. The IP route table with the BGP4 route is shown here.
Virtual ADX# 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 Metric LocPrf Weight Status
1 0.0.0.0/0 10.1.0.2 0 100 0 BI
AS_PATH: 65001 4355 701 80
2 10.0.0.0/24 10.0.0.1 1 100 0 BI
AS_PATH: 65001 4355 1
3 10.0.0.0/24 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
10.0.0.0/24
10.157.24.1 1 100 0 I
AS_PATH: 65001 4355 701
Virtual ADX# show ip route 10.2.0.1
Total number of IP routes: 38
Start index: 1 B:BGP Be:EBGP Bi:IBGP D:Connected S:Static
O:OSPF IA:Inter area IR:Intra area E1:External type 1 E2:External type 2
(N): Don't advertise *:Candi-default
Destination
NetMask
Gateway
Port
Cost
Type
--------------------------------------------------------------------------
1
10.2.0.0
255.255.255.0
10.0.0.1
1/1
1
B
AS_PATH: 65001 4355 1
Virtual ADX# show ip bgp route 10.0.0.0
Number of BGP Routes matching display condition : 1
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 Metric LocPrf Weight Status
1 10.0.0.0/24 10.0.0.1 1 100 0 BI
AS_PATH: 65001 4355 1
Virtual ADX# show ip route 10.0.0.1
Total number of IP routes: 38
Start index: 1 B:BGP Be:EBGP Bi:IBGP D:Connected S:Static
O:OSPF IA:Inter area IR:Intra area E1:External type 1 E2:External type 2
(N): Don't advertise *:Candi-default
Destination NetMask
Gateway
Port
Cost
Type
--------------------------------------------------------------------------
1
10.0.0.0
255.255.255.0
0.0.0.0
1/1
1
D
AS_PATH: 65001 4355 1