Figure 57: MPLS Interface Stacking for the Interface Label Space
Related Topics MPLS Label Distribution Methodology on page 227•
• MPLS Label Switching and Packet Forwarding Overview on page 218
• MPLS Label Distribution Protocols Overview on page 238
MPLS Label Distribution Protocols Overview
Label distribution protocols create and maintain the label-to-FEC bindings along an LSP
from MPLS domain ingress to MPLS domain egress. A label distribution protocol is a set
of procedures by which one LSR informs a peer LSR of the meaning of the labels used
to forward traffic between them. It enables each peer to learn about the other peer’s
label mappings. The label distribution protocol provides the information MPLS uses to
create the forwarding tables in each LSR in the MPLS domain.
NOTE: Label distribution protocols are sometimes referred to as signaling protocols.
However, label distribution is a more accurate description of their function and is
preferred in this text.
The following protocols are currently used for label distribution:
•
BGP—Border Gateway Protocol
•
LDP—Label Distribution Protocol
•
RSVP-TE—Resource Reservation Protocol with traffic-engineering extensions that
enable label binding and explicit route capability
NOTE: To reduce confusion, this text uses the lowercase term, label distribution protocol,
to refer to the generic class of protocols. The acronym, LDP, refers only to the particular
protocol named Label Distribution Protocol.
BGP and LDP have no traffic-engineering capability and support only best-effort LSPs.
LDP supports topology-driven MPLS networks in best-effort, hop-by-hop
implementations. RSVP-TE is used primarily for MPLS applications that require traffic
Copyright © 2010, Juniper Networks, Inc.238
JunosE 11.2.x BGP and MPLS Configuration Guide
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