Juniper JUNOSE 11.2.X BGP AND MPLS, Configuration Manual

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You can use the ip mpls forwarding-mode label-switched command to configure the
router to generate a label for each different FEC that a BGP route points to in the VPN;
this is a per-FEC label. Issuing this command enables you to avoid a route lookup for
traffic destined for CE routers, because in this mode traffic is label switched to the
corresponding next hop over that interface; a route lookup is not performed.
The route for which a label is allocated can be an ECMP route; in that case, the
label-switched traffic uses ECMP.
For the following types of routes, the router always generates a per-VRF label and
forwards traffic after a route lookup (rather than label switching the traffic without a
route lookup) regardless of the status of this command:
•
Local connected interfaces redistributed into BGP, regardless of the interface type.
• BGP redistributed routes that point to loopback interfaces.
The following commands configure a router where BGP is running in VRF pe11 and static
and connected routes are redistributed into the VRF:
host1(config)# ip vrf pe11
host1(config-vrf)# ip mpls forwarding-mode label-switched
host1(config-vrf)# ip route vrf pe11 10.3.4.5 255.255.255.255 fastEthernet 0/1
host1(config-vrf)# ip route vrf pe11 10.1.1.1 255.255.255.255 loopback 1
host1(config-vrf)# exit
host1(config)# router bgp 100
host1(config-router)# address-family ipv4 unicast vrf pe11
host1(config-router-af)# exit
host1(config-router)# no auto-summary
host1(config-router)# no synchronization
host1(config-router)# redistribute static
host1(config-router)# redistribute connected
For each connected route that is redistributed into the VRF and advertised across the
BGP/MPLS VPN, the router assigns a per-VRF label rather than a per-FEC label.
The static route 10.1.1.1/32 points to loopback interface 1. BGP therefore advertises this
static route with a per-VRF label.
ip mpls forwarding-mode label-switched
•
Use to generate a label for each different FEC pointed to by a BGP route.
•
For some types of routes, issuing this command has no effect on the labels created;
they are always per-VRF labels.
•
Example
host1:vr1(config-vrf)# ip mpls forwarding-mode label-switched
•
Use the no version to restore the default, generating a single label for all BGP routes
sent from a given VRF.
•
See ip mpls forwarding-mode label-switched.
Copyright © 2010, Juniper Networks, Inc. 440
JunosE 11.2.x BGP and MPLS Configuration Guide