Juniper JUNOSE SOFTWARE FOR E SERIES 11.0.X - BGP AND MPLS CONFIGURATION GUIDE 2009-12-30 Configuration Manual page 468

JUNOSe 11.0.x BGP and MPLS Configuration Guide
Disabling Automatic Route-Target Filtering
When BGP receives a VPN-IPv4 or VPN-IPv6 route from another PE router, BGP stores
that route in its local routing table only if at least one VRF imports a route target of
that route. If no VRF imports any of the route targets of the route, BGP discards the
route; this feature is called automatic route-target filtering. The intention is that BGP
keeps track of routes only for directly connected VPNs, and discards all other VPN-IPv4
or VPN-IPv6 routes to conserve memory.
If a new VPN is connected to the router (that is, if the import route-target list of a
VRF changes), BGP automatically sends a route-refresh message to obtain the routes
that it previously discarded.
You can use the no bgp default route-target filter command to disable automatic
route-target filtering globally for all VRFs. However, automatic route-target filtering
is always disabled on route reflectors that have at least one route-reflector client.
You cannot enable automatic route-target filtering for such route reflectors.
bgp default route-target filter
Creating Labels per FEC
By default, the router minimizes the number of stacked labels to be managed by
generating a single label for all BGP routes advertised by a given VRF; this is a per-VRF
label. Upon receiving traffic for a per-VRF label, the router performs a label pop and
a route lookup to forward the traffic to the next hop.
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Configuring BGP VPN Services
You must use the no ip vrf command to remove a VRF. Issuing a no version of
this command (no virtual-router : vrfName or no virtual-router vrName :
vrfName) that specifies an existing VRF only displays the error message:
Cannot delete a VRF with this command"
See virtual-router.
Use to control automatic route-target filtering.
Route-target filtering is enabled by default.
Takes effect immediately. When route target filtering is turned on, this command
immediately removes routes to be filtered.
If route-target filtering is turned off, BGP automatically sends out a route-refresh
message over every VPNv4 or VPNv6 unicast session (for which the route-refresh
capability was negotiated) to get previously filtered routes. If the route-refresh
capability was not negotiated over the session, BGP bounces the session.
Example
host1:vrf1(config-router)#no bgp default route-target filter
Use the no version to disable automatic route-target filtering.
See bgp default route-target filter.