Conditions For Advertising Rt-Mem-Nlri Routes; Advertising A Default Route - Juniper BGP - CONFIGURATION GUIDE V 11.1.X Configuration Manual

JUNOSe 11.1.x BGP and MPLS Configuration Guide
neighbor maximum-prefix

Conditions for Advertising RT-MEM-NLRI Routes

The following conditions must be met for routes in the route-target address family
to be advertised to a BGP peer:
1.
2.
In a VRF, a RT-MEM-NLRI attribute represented by (origin AS number:route target)
is advertised for every route target added to the VRF's route target import list when
the preceding conditions have been met.
A withdrawal for the RT-MEM-NLRI attribute is generated when the route target is
removed from this VRF's import list.

Advertising a Default Route

You can configure BGP to send a default route to indicate that the speaker accepts
routes for any VPNs associated with any route target. For example, this might be
desirable for a route reflector advertising to one of its PE router clients, or when a
VPN provider is migrating the network to route-target filtering but one or more PEs
in the provider's network do not support this feature.
414
Constraining Route Distribution with Route-Target Filtering
Use to control how many prefixes can be received from a neighbor.
If you specify a BGP peer group by using the peerGroupName argument, all the
members of the peer group inherit the characteristic configured with this
command unless it is overridden for a specific peer.
By default, BGP checks the maximum prefix limit only against accepted routes.
You can specify the strict keyword to force BGP to check the maximum prefix
against all received routes. The accepted and received routes will likely differ
when you have configured inbound soft reconfiguration and route filters for
incoming traffic.
This command takes effect immediately. To prevent a peer from continually
flapping, when it goes to state idle because the maximum number of prefixes
has been reached, the peer stays in state idle until you use the clear ip bgp
command to issue a hard clear.
Example
host1(config-router)#address-family route-target signaling
host1(config-router-af)#neighbor maximum-prefix 10.1.2.3 100
Use the no version to remove the maximum number of prefixes.
See neighbor maximum-prefix.
The BGP peers have successfully negotiated the route-target address family.
The import route-target list for the IPv4 VRF is not empty or is transitioning to
empty.