Brocade Multi-Service IronWare Routing Configuration Guide Uživatelský manuál stáhnout pdf (Strana 94)

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66 Multi-Service IronWare Routing Configuration Guide

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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 /jointfilesconvert/1441120/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