ramd.conf.4 (2010 09)

r
ramd.conf(4) ramd.conf(4)
route_filter filter-name {
[as asnum]
[(prefix prefixlength)|(
hosthost-address)|all]
[
aspath aslist]
dir (in|out);}
(allow|restrict);
where:
as asnum Specifies the remote autonomous system (AS) number based on which
bgpd applies
the filter.
prefix prefixlength Specifies the route prefix based on which
bgpd applies the filter.
host host-address
Specifies the host routes on which
bgpd applies this filter.
all Specifies bgpd to filter all routes.
aspath aslist Specifies the AS path list based on which
bgpd applies this filter.
dir (in|out) Specifies the direction of update messages on which
bgpd applies this filter. The
in
option applies the filter on incoming routes and the
out option applies the filter on
outgoing routes.
allow|restrict;
Specifies to allow or restrict the incoming or outgoing routes. By default, bgpd allows
all routes.
Route Aggregation for BGP
Route aggregation is the process of merging two or more routes to form a single route on the basis of
matching bits in each route. It reduces the number of routes in the BGP route update message. The
receiving BGP neighbor router installs the aggregate route in the kernel routing table. Hence, route
aggregation reduces the number of routes in the kernel routing table.
bgpd that generates aggregate
routes do not use the originated aggregate routes for packet forwarding.
The aggregate configuration statement can be used to generate aggregate routes. If the aggregate
configuration statement is not specified in the configuration file,
bgpd does not perform route aggrega-
tion. Route aggregation is effective only when the
overlap both configuration statement is specified.
The syntax of the
aggregate configuration statement is as follows:
aggregate {
[prefix prefixlength
[all|summary-only]
[preference preference-value]
[
restrict]];
};
where:
prefix prefixlength Specifies the routes that can be aggregated and its prefix length.
all|summary-only
Specifies bgpd to advertise aggregated routes and more specific routes or advertise
only aggregated routes.
preference preference-value
Specifies the preference for the aggregated routes. By default, this value is 130.
restrict Specifies that bgpd must not aggregate with this route.
Local Preference (LP) for BGP
bgpd uses the defaultlocalpref configuration statement to set the preference value:
defaultlocalpref preference-value;
where preference-value specifies the default LP value.
The BGP section in the RAMD configuration file specifies the value for local preference attribute.
bgpd
uses the localpref configuration to set preference value based on autonomous system (AS) number, AS
path or prefix. Routes with higher local preference value is preferred to those with a low preference
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