Juniper JUNOSE 11.2.X BGP AND MPLS

Example 1 The following commands announce the tunnel to OSPF and specify a relative metric of
-2:
host1(config-if)#tunnel mpls autoroute announce ospf
host1(config-if)#tunnel mpls autoroute metric relative -2
By default, the LSP is preferred to reach the tunnel endpoint. OSPF will treat this LSP as
having a metric of 2 less than the shortest path metric it has calculated. The LSP is
therefore also preferred over other paths to prefixes beyond the tunnel endpoint.
Example 2 The following commands announce the tunnel to OSPF, specify an absolute metric of
25, and configure OSPF to enable the consideration of SPF best paths:
host1(config-if)#tunnel mpls autoroute announce ospf
host1(config-if)#tunnel mpls autoroute metric absolute 25
...
host1(config)#router ospf 1
host1(config-router)#mpls spf-use-any-best-path
OSPF uses this metric in its SPF calculations for traffic to the tunnel endpoint as well as
beyond the endpoint. Traffic is routed through this LSP only when the other calculated
paths have higher metrics.
Configuring the IGPs for Traffic Engineering
For both IGPs, you must issue two commands to enable the IGP to support traffic
engineering.
•
IS-IS—Enable the flooding of MPLS traffic-engineering link information into the specified
IS-IS level with the mpls traffic-eng command. You must also specify a stable router
interface with the mpls traffic-eng router-id command.
MPLS traffic engineering also requires that IS-IS generate the new-style TLVs that
enable wider metrics. Use the metric-style wide command to generate the new-style
TLVs. If you are using some IS-IS routers that still cannot interpret the new-style TLVs,
use the metric-style transition command.
•
OSPF—Enable OSPF areas for traffic engineering with the mpls traffic-eng area
command. OSPF generates opaque LSAs—also known as type-10 opaque link area
link states—to flood the traffic-engineering information to the specified area. OSPF
builds a traffic-engineering database that it uses in the calculation of shortest path to
destinations that satisfy specified traffic-engineering constraints. As with IS-IS, you
must also specify a stable router interface with the mpls traffic-eng router-id
command.
To enable a multicast network and MPLS traffic engineering (TE) network to
interoperate on a router running OSPF, use the mpls traffic-eng multicast-intact
command.
When you configure a node as the downstream endpoint of an LSP, you must provide a
stable interface as the router ID for the endpoint. Typically you select a loopback interface
because of its inherent stability. Use the mpls traffic-eng router-id command to designate
the router as traffic engineering capable and to specify the router ID. For all tunnels that
Copyright © 2010, Juniper Networks, Inc.302
JunosE 11.2.x BGP and MPLS Configuration Guide