Netgear XCM8806 - 8800 SERIES 6-SLOT CHASSIS SWITCH ユーザーズマニュアル
Chapter 26. BGP
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NETGEAR 8800 User Manual
When BGP inactive route advertising is enabled, inactive BGP routes are considered for
BGP route aggregation. When this feature is disabled, inactive BGP routes are ignored while
aggregating routes.
BGP route aggregation. When this feature is disabled, inactive BGP routes are ignored while
aggregating routes.
Default Route Origination and Advertisement
The default route origination and advertisement feature allows you to originate and advertise
a default route to a BGP neighbor (or to all neighbors in a peer group) even though no default
route exists in the local IP routing table. It also allows you to associate policy rules to
conditionally advertise a default route to BGP neighbors.
a default route to a BGP neighbor (or to all neighbors in a peer group) even though no default
route exists in the local IP routing table. It also allows you to associate policy rules to
conditionally advertise a default route to BGP neighbors.
When default route origination becomes active, the default route is advertised to the specified
BGP neighbors, overriding any previously sent default route. If a default route is added to the
local IP routing table while default route origination is active, the default route defined by this
feature takes precedence over the new regular default route. If default route origination
becomes inactive, and a regular default route exists, the regular default route is advertised to
BGP neighbors.
BGP neighbors, overriding any previously sent default route. If a default route is added to the
local IP routing table while default route origination is active, the default route defined by this
feature takes precedence over the new regular default route. If default route origination
becomes inactive, and a regular default route exists, the regular default route is advertised to
BGP neighbors.
The following sections provide additional information on this feature:
Managing Policies for Default Route Origination
When you use a policy with default route origination, the default route is originated only if the
local BGP RIB contains a route that matches the policy match conditions. You can use the
following match conditions:
local BGP RIB contains a route that matches the policy match conditions. You can use the
following match conditions:
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NLRI
•
AS-path
•
Community
•
Origin
You can also use the following policy actions in the policy to set the route attributes:
•
AS-path
•
Community
•
Origin
After a policy is configured for default route origination, BGP must periodically scan the local
BGP RIB to make sure that the policy rules evaluate to true for at least one route in local BGP
RIB. If the rules evaluate to true, default origination remains active. If the rules evaluate to
false, then default origination becomes inactive and the default routes must be withdrawn.
BGP RIB to make sure that the policy rules evaluate to true for at least one route in local BGP
RIB. If the rules evaluate to true, default origination remains active. If the rules evaluate to
false, then default origination becomes inactive and the default routes must be withdrawn.
For more information on policy match conditions, actions, and configuration, see