Multicast and Routing Guide K/KA/KB.15.15

Synchronizing BGP-IGP
Table 35 BGP-IGP synchronization commands
Menu referenceCLI referenceDefaultDescriptionCommand syntax
(page 302)Specifies routes to
export into BGP. This
[no] redistribute
protocol
command causes
[route-map
route-map-name]
routes from the
specified protocol to
be considered for
redistribution into
BGP.
(page 302)Route maps control the
redistribution of routes
between protocols.
[no] neighbor
ipv4-addr
route-map
route-map-name
[[in] | [out]]
Specifying routes to export into BGP
Syntax:
[no] redistribute protocol [route-map route-map-name]
Specifies routes to export into BGP. This command causes routes from the specified protocol to be
considered for redistribution into BGP. Additionally, if a route map is specified, then routes from
the specified protocol that match the named route map will be considered for redistribution into
the current protocol. If the referenced route map has not yet been configured, then an empty route
map is created with the specified name.
Specifying route map to be exported in or out of BGP
Syntax:
[no] neighbor ipv4-addr route-map route-map-name [[in] | [out]]
Route maps control the redistribution of routes between protocols. Only after
configuring a route map, can it then be specified in BGP. Use this command to
specify a configured route map to be exported into or out of BGP. When the in
version of this command is configured, all IPv4 announcements received from the
specified neighbor should be run against the policy specified in the named
route-map. When the out version of this command is used, it specifies that all IPv4
announcements sent to the specified neighbor should be run against the policy
specified in the named route-map. After evaluating this policy, each route will be
compared to the specified route-target export, to see if announcement is acceptable.
BGP path attributes
Classification of path attributes
There are four categories of path attributes:
Well-known mandatory Must be recognized by all BGP routers and must be included
in every update message. Routing information errors occur
without this attribute.
Well-known discretionary Can be recognized by all BGP routers; can be included in
every update message as needed.
302 Border Gateway Protocol (BGP)