Attach an IP output policy for the plain VPN service to CE interfaces on the PE router
for outgoing traffic. The same plain-service policy that is attached to the input in
Step 2 can be used on output, although the UPC setting is not needed.
host1(config)#Interface atm 5/0.1
host1(config-subif)#Ip policy output plain-service
4. For traffic toward the core, configure per-VR rules or per-LSP policies to set the base
EXP bits value according to the traffic-class/color combination. Issue the mpls
copy-upc-to-exp command to set the VPN EXP bits value to the UPC value. The
UPC value is the same as the IP precedence value for the QoS service case; for all
other cases the value is 000. Configure the mpls preserve-vpn-exp command so
that VPN EXP bits are not subject to policy or to per-VR EXP rules.
host1(config)#mpls match traffic-class … color … set exp-bits …
host1(config)#mpls copy-upc-to-exp
host1(config)#mpls preserve-vpn-exp
You must attach a policy to the core-side IP interface to set the UPC value of the
control traffic appropriately so that the EXP bits value is copied from the UPC when
this traffic goes out as MPLS packets.
host1(config)#ip classier-list control-traffic-prec0 …
host1(config)#ip classier-list control-traffic-prec1 …
host1(config)#ip policy-list core-ip-policy
host1(config-policy-list)#classifier-group control-traffic-prec0
host1(config-policy-list-classifier-group)#user-packet-class prec0
host1(config-policy-list-classifier-group)#traffic-class class0
host1(config-policy-list-classifier-group)#color green
host1(config-policy-list)#classifier-group control-traffic-prec1
host1(config-policy-list-classifier-group)#-packet-class prec1
host1(config-policy-list-classifier-group)#traffic-class class1
host1(config-policy-list-classifier-group)#color green
host1(config)#interface pos 0/0
host1(config-subif)ip policy output core-ip-policy
5. For traffic from the core, configure per-VR rules or per-LSP policies to set the
traffic-class/color combination—and therefore shape the egress traffic
queue—according to the value of the EXP bits in the base label. This action causes
host1(config)#mpls match exp-bits <value> set traffic-class <className> color
Related Topics Configuring MPLS and Differentiated Services on page 303•
• Configuring EXP Bits for Differentiated Services on page 304
• Classifying Traffic for Differentiated Services on page 307
Classifying Traffic for Differentiated Services
In a differentiated services domain, traffic is classified into a behavior aggregate (BA),
based on the type of diff-serv behavior for the traffic. At each node, traffic belonging to
a particular BA is mapped to the corresponding per-hop behavior (PHB), which provides
the scheduling behavior and drop probability required by the traffic.
307Copyright © 2010, Juniper Networks, Inc.
Chapter 4: Configuring MPLS
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