Juniper JUNOSE 11.2.X BGP AND MPLS, Руководство по настройке

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Global Import Maps
Global import maps enable BGP routes to be imported from the global BGP non-VPN
RIB into the BGP RIB of a VRF based on a configured route map. You can use import
maps as an automated mechanism that enables a subset of the Internet to be reachable
from a VPN. This feature is intended to provide simplified central access to a limited
number of centralized services in the provider network. Use this feature to import only a
relatively small number (tens) of routes from the global domain into the VPNs, such as
a small number of routes to DNS servers, content servers, management stations, and so
on.
If instead you import the full Internet routing table into one or more VPNs, too much
memory will be consumed because this action stores multiple copies of the full Internet
routing table. To prevent an accidental misconfiguration, you must specify the maximum
number of routes to be imported into a VRF when you configure global import. If you
must provide access to the full Internet from a VPN, use the
fallback global command.
global import map
•
Use to apply a route map to a VRF to modify and filter routes imported to the BGP RIB
of the VRF from the global BGP non-VPN RIB in the parent VR.
•
You can specify that only IPv4 or only IPv6 routes are imported. By default, both types
of routes are imported.
•
Use the max-routes keyword to specify the maximum number of routes that you want
to be imported into the local RIB. BGP generates a log message when the specified
number of routes has been imported; no additional routes are imported.
WARNING 02/11/2005 10:28:35 bgpRoutes (default,10.13.5.21): Maximum number of
routes (5000) imported from global RIB into RIB of VRF foo.
•
Changes to the maximum number of routes take effect immediately.
•
Example
host1:boston(config-vrf)# global import map routemap22 max-routes 512
•
Use the no version to disable the importing of routes from the global BGP non-VPN
RIB to the BGP RIB of the VRF.
•
See global import map.
Global Export of IPv6 VPN Routes into the Global BGP IPv6 RIB
VPNv6 routes can be exported from the BGP RIB of an IPv6 VRF to the global IPv6 BGP
RIB based on policy by means of a route map and the
global export map command.
For example, if you have a mixed IPv4 and IPv6 VPN configuration, but want only the
IPv6 VPN routes to be exported from the IPv6 VRF into the global IPv6 RIB, you can use
a route map that matches on IPv6 access-lists (IPv6 prefix-lists). You can have the route
map disallow IPv4 VPN routes by matching on IPv4 access lists that filter out IPv4 prefixes.
The following commands illustrate this behavior.
• Configure an IPv6 access list to export IPv6 VPN prefixes to the global IPv6 RIB.
433 Copyright © 2010, Juniper Networks, Inc.
Chapter 6: Configuring BGP-MPLS Applications