ECS4660-28F_Management Guide-R03

C HAPTER 51 | IP Routing Commands
Policy-based Routing for BGP
– 1898 –
is used to determine the packet’s next hop. Although route redistribution is
protocol-independent, some of the route-map match and set commands
defined in this section are specific to BGP.
Like matches in the same route map subblock are filtered with “or”
semantics. If any one match clause is matched in the entire route map
subblock, this match is treated as a successful match. Dissimilar match
clauses are filtered with “and” semantics. If the first set of conditions is not
met, the second match clause is filtered. This process continues until a
match occurs or there are no more match clauses.
A route map can have several sequences. A route that does not match at
least one match command defined in a route-map will be ignored; that is,
the route will not be advertised for outbound route maps nor accepted for
inbound route maps.
Table 276: Policy-based Routing Configuration Commands
Command Function Mode
route-map Enters route-map configuration mode, allowing route
maps to be created or modified
GC
call Jumps to another route map after match and set
commands are executed
RM
continue Goes to a route-map entry with a higher sequence
number after a successful match occurs
RM
description Creates a description of an entry in the route map RM
match as-path Sets an AS path access list to match RM
match community Sets a BGP community access list to match RM
match extcommunity Sets a BGP extended community access list to match RM
match ip address Specifies destination addresses to match in a standard
access list, extended access list, or prefix list
RM
match ip next-hop Specifies next hop addresses to match in a standard
access list, extended access list, or prefix list
RM
match ip route-source Specifies the source of routing messages to match in a
standard access list, extended access list, or prefix list
RM
match metric Sets the metric value to match in routing messages RM
match origin Sets the originating protocol to match in routing
messages
RM
match pathlimit as Sets the maximum AS path length for propagation of
more specific prefixes to match in routing messages
RM
match peer Sets the peer address to match in routing messages RM
on-match Sets the next entry to go to when this entry matches RM
set aggregator as Assigns an AS number and IP address to the
aggregator attribute of a route
RM
set as-path Modifies the AS path by prepending or excluding an AS
number
RM
set atomic-aggregate Indicates the loss of some information in the route
aggregation process
RM
set comm-list delete Removes communities from the community attribute
of inbound or outbound routing messages
RM