Juniper JUNOS OS 10.3 - SOFTWARE, Manual, Page: 3448 / 3946

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Packets arriving on different ports can be assigned different labels.
• A packet arriving at a particular provider edge switch may be assigned a label that is
different from that of the same packet entering the network at a different provider
edge switch. As a result, forwarding decisions that depend on the ingress provider edge
switch can be easily made.
• Sometimes it is desirable to force a packet to follow a particular route that is explicitly
chosen at or before the time the packet enters the network, rather than letting it follow
the route chosen by the normal dynamic routing algorithm as the packet travels through
the network. In MPLS, a label can be used to represent the route so that the packet
need not carry the identity of the explicit route.
NOTE: MPLS configurations on EX Series switches do not support:
• LDP-based MPLS
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Routed VLAN interfaces (RVIs)
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Q-in-Q tunneling
• Aggregated Ethernet interfaces (LAGs) on CCCs
• CCCs with a beginning and ending on the same switch
Additional Benefits of MPLS and Traffic Engineering
MPLS is the packet-forwarding component of the Junos traffic engineering architecture.
Traffic engineering provides the capabilities to do the following:
• Route primary paths around known bottlenecks or points of congestion in the network.
• Provide precise control over how traffic is rerouted when the primary path is faced with
single or multiple failures.
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Provide efficient use of available aggregate bandwidth and long-haul fiber by ensuring
that certain subsets of the network are not overutilized while other subsets of the
network along potential alternate paths are underutilized.
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Maximize operational efficiency.
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Enhance the traffic-oriented performance characteristics of the network by minimizing
packet loss, minimizing prolonged periods of congestion, and maximizing throughput.
• Enhance statistically bound performance characteristics of the network (such as loss
ratio, delay variation, and transfer delay) required to support a multiservice Internet.
Related
Documentation
Understanding MPLS Label Operations on EX Series Switches on page 3361
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Understanding JUNOS MPLS Components for EX Series Switches on page 3353
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Understanding Using CoS with MPLS Networks on EX Series Switches on page 3167
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Example: Configuring MPLS on EX Series Switches on page 3365
Copyright © 2010, Juniper Networks, Inc. 3352
Complete Software Guide for Junos
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OS for EX Series Ethernet Switches, Release 10.3