Loopback Interfaces; What Is A Route Map - Lenovo RackSwitch G8264 Application Manual

Loopback Interfaces

What is a Route Map?

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G8264 Application Guide for ENOS 8.4
In many networks, multiple connections may exist between network devices. In
such environments, it may be useful to employ a loopback interface for a common
BGP router address, rather than peering the switch to each individual interface.
Note: To ensure that the loopback interface is reachable from peer devices, it must
be advertised using an interior routing protocol (such as OSPF), or a static route
must be configured on the peer.
To configure an existing loopback interface for BGP neighbor, use the following
commands:
RS G8264(config)# router bgp
RS G8264(config­router­bgp)# neighbor <#> update­source loopback <1‐5>
RS G8264(config­router­bgp)# exit
A route map is used to control and modify routing information. Route maps define
conditions for redistributing routes from one routing protocol to another or
controlling routing information when injecting it in and out of BGP. For example, a
route map is used to set a preference value for a specific route from a peer router
and another preference value for all other routes learned via the same peer router.
For example, the following command is used to enter the Route Map mode for
defining a route map:
RS G8264(config)# route­map <map number>(Select a route map)
A route map allows you to match attributes, such as metric, network address, and
AS number. It also allows users to overwrite the local preference metric and to
append the AS number in the AS route. See "BGP Failover Configuration" on
page 549.
Enterprise NOS allows you to configure 255 route maps. Each route map can have
up to 32 access lists. Each access list consists of a network filter. A network filter
defines an IPv4 address and subnet mask of the network that you want to include
in the filter. Figure 45 illustrates the relationship between route maps, access lists,
and network filters.