Juniper BGP - CONFIGURATION GUIDE V 11.1.X Configuration Manual page 634

JUNOSe 11.1.x BGP and MPLS Configuration Guide
interface with a VPLS instance named vplsBoston, and configure the interface as a
trunk.
If you configure a VPLS network interface as a subscriber (client) interface, use care
if you modify the default subscriber policy in effect for that interface. For example,
if you use the arp command to change the default value for ARP packets from permit
(forward) to deny (filter or drop), make sure you also use the bridge address command
to add the appropriate static (nonlearned) ARP entry to the forwarding table. If an
ARP entry expires from the forwarding table and the subscriber policy is configured
to deny ARP packets, the router cannot properly forward subsequent ARP packets.
Related Topics
Configuring the Loopback Interface and Router ID for VPLS
A loopback interface provides a stable address for BGP or LDP to use so that they
can avoid any impact if a physical interface goes down. The loopback interface sends
packets back to the router or access server for local processing. Any packets routed
from the loopback interface, but not destined to the loopback interface, are dropped.
To establish a BGP session, BGP uses the IP address of the outgoing interface towards
the BGP peer as the update source IP address for the TCP connection over which the
BGP session runs. Typically, you configure a loopback interface as the update source
interface.
LDP uses the loopback interface as the associated interface for the targeted neighbors
configured with the mpls ldp vpls neighbor command, as described in "Configuring
LDP Signaling for VPLS" on page 607.
After you configure the loopback interface, you use the ip router-id command to
assign a router ID to uniquely identify the router within a BGP AS. The router ID is
the IP address of the loopback interface.
To configure the loopback interface and router ID on the PE router:
1.
2.
598
Configuring the Loopback Interface and Router ID for VPLS
host1(config)#interface tenGigabitEthernet 4/0/1
host1(config-if)#bridge-group vplsBoston subscriber-trunk
Configuration Tasks for VPLS with BGP Signaling on page 590
Configuration Tasks for VPLS with LDP Signaling on page 605
For information about using these commands, see Configuring Secure Policies in
the JUNOSe Link Layer Configuration Guide.
Configure a loopback interface on the PE router and assign it an IP address.
host1(config)#interface loopback 0
host1(config-if)#ip address 10.3.3.3 255.255.255.255
host1(config-if)#exit
Assign the router ID using the IP address you configured for the loopback
interface.
host1(config)#ip router-id 10.3.3.3