If you issue the
neighbor default-originate
command, BGP sends the default route
to that neighbor regardless of whether the default route exists in the IP forwarding
table.
In Figure 15 on page 56, router NY originates the default route 0.0.0.0/0 to router
Albany only. Router Chicago does not receive the default route.
Figure 15: Advertising a Default Route
To configure router NY:
host1(config)#
router bgp 200
host1(config-router)#
network 192.168.42.0 mask 255.255.254.0
host1(config-router)#
neighbor 10.3.3.1 remote-as 300
host1(config-router)#
neighbor 192.168.10.2 remote-as 100
host1(config-router)#
neighbor 192.168.10.2 default-originate
You can also specify a route map to modify the attributes of the default route. If the
default route does not match the route map, then the default route is not advertised.
Redistributing Default Routes
By default, the
redistribute
command does not permit a default route to be
redistributed into BGP. You can use the
default-information originate
command to
override this behavior and permit the redistribution of default routes into BGP.
default-information originate
■
Use to enable the redistribution of default routes into BGP.
■
Use the
route-map
keyword to specify outbound route maps to apply to the
default route. The route map can modify the attributes of the default route.
■
This command takes effect immediately. However, if the contents of the route
map specified with this command change, the new route map may or may not
take effect immediately. If the
disable-dynamic-redistribute
command has
been configured, you must issue the
clear ip bgp redistribution
command to
apply the changed route map.
■
Outbound policy configured for the neighbor (using the
neighbor route-map
out
command) is applied to default routes that are advertised because of the
default-information originate
command.
56
■
Advertising Routes
JUNOSe 11.1.x BGP and MPLS Configuration Guide
Summary of Contents for BGP
Page 6: ...vi ...
Page 8: ...viii JUNOSe 11 1 x BGP and MPLS Configuration Guide ...
Page 37: ...Part 1 Border Gateway Protocol Configuring BGP Routing on page 3 Border Gateway Protocol 1 ...
Page 38: ...2 Border Gateway Protocol JUNOSe 11 1 x BGP and MPLS Configuration Guide ...
Page 234: ...198 Monitoring BGP JUNOSe 11 1 x BGP and MPLS Configuration Guide ...
Page 236: ...200 Multiprotocol Layer Switching JUNOSe 11 1 x BGP and MPLS Configuration Guide ...
Page 542: ...506 Monitoring BGP MPLS VPNs JUNOSe 11 1 x BGP and MPLS Configuration Guide ...
Page 544: ...508 Layer 2 Services Over MPLS JUNOSe 11 1 x BGP and MPLS Configuration Guide ...
Page 610: ...574 Virtual Private LAN Service JUNOSe 11 1 x BGP and MPLS Configuration Guide ...
Page 624: ...588 VPLS References JUNOSe 11 1 x BGP and MPLS Configuration Guide ...
Page 680: ...644 Virtual Private Wire Service JUNOSe 11 1 x BGP and MPLS Configuration Guide ...
Page 724: ...688 Monitoring MPLS Forwarding Table for VPWS JUNOSe 11 1 x BGP and MPLS Configuration Guide ...
Page 725: ...Part 6 Index Index on page 691 Index 689 ...
Page 726: ...690 Index JUNOSe 11 1 x BGP and MPLS Configuration Guide ...