You must enable IP routing on the device for Multitopology Routing (MTR) to operate. MTR supports static and dynamic routing
in Cisco software. You can enable dynamic routing per topology to support interdomain and intradomain routing. Route calculation
and forwarding are independent for each topology. MTR support is integrated into Cisco software for the following protocols:
You apply the per-topology configuration in router address family configuration mode of the global routing process (router
configuration mode). The address family and subaddress family are specified when the device enters address family configuration
mode. You specify the topology name and topology ID by entering the
topology command in address family configuration mode.
You configure each topology with a unique topology ID under the routing protocol. The topology ID is used to identify and
group Network Layer Reachability Information (NLRI) for each topology in updates for a given protocol. In OSPF, EIGRP, and
IS-IS, you enter the topology ID during the first configuration of the
topology command for a class-specific topology. In BGP, you configure the topology ID by entering the
bgp tid command under the topology configuration.
You can configure class-specific topologies with different metrics than the base topology. Interface metrics configured on
the base topology can be inherited by the class-specific topology. Inheritance occurs if no explicit inheritance metric is
configured in the class-specific topology.
You configure BGP support only in router configuration mode. You configure Interior Gateway Protocol (IGP) support in router
configuration mode and in interface configuration mode.
By default, interfaces are not included in nonbase topologies. For routing protocol support for EIGRP, IS-IS, and OSPF, you
must explicitly configure a nonbase topology on an interface. You can override the default behavior by using the
all-interfaces command in address family topology configuration mode. The
all-interfaces command causes the nonbase topology to be configured on all interfaces of the device that are part of the default address
space or the virtual routing and forwarding (VRF) instance in which the topology is configured.