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JUNOSe 11.0.x BGP and MPLS Configuration Guide
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MPLS Forwarding and Next-Hop Tables
An MPLS forwarding table determines how MPLS handles received MPLS packets.
When an MPLS packet arrives on an MPLS major interface, MPLS looks up the
outermost MPLS label of the received packet in the relevant MPLS forwarding table.
The entries in the MPLS forwarding table map labels to next hops. Each entry in the
MPLS forwarding table points to an entry in the MPLS next-hop table. Each MPLS
next hop points to either an interface or another MPLS next hop. The chain of MPLS
next hops, which ends at an interface, informs MPLS which labels to push and where
to send the MPLS packet.
For RSVP-TE tunnels, minor interfaces are created in addition to the forwarding table
and next-hop table entries. One minor interface is created of each in/out segment
of a tunnel. the purpose of these minor interfaces is to attach QoS and policy to an
LSP.
MPLS forwarding tables consist of the following:
The signaling protocols add entries to the MPLS forwarding tables. You cannot
manually create an MPLS forwarding entry. The signaling protocols set the following
attributes for each entry placed in the forwarding table:
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MPLS Forwarding and Next-Hop Tables
Adjacency statistics:
30 hello recv, 29 hello sent, 0 bad hello recv
adj setup time = 00:02:19
last hello recv time = 00:00:00, last hello sent time = 00:00:00
queue 0: traffic class best-effort, bound to atm-vc ATM9/0.10
Queue length 0 bytes
Forwarded packets 1, bytes 148
Dropped committed packets 0, bytes 0
Dropped conformed packets 0, bytes 0
Dropped exceeded packets 0, bytes 0
Mapping IP Data Packets onto MPLS LSPs on page 220
One forwarding table for each MPLS virtual router. This table contains labels
from the platform label space. When an MPLS packet arrives on an MPLS major
interface that uses the platform label space, MPLS looks up the label in the MPLS
forwarding table of the virtual router in which the major interface exists.
One forwarding table for each MPLS major interface that uses the interface label
space. This table contains labels from the interface label space of that major
interface. When an MPLS packet arrives on an MPLS major interface that uses
the interface label space, MPLS looks up the label in the MPLS forwarding table
for that particular major interface.
An MPLS in label that is matched against the outermost label of the received
MPLS packet.
The MPLS next hop, which specifies the actions to be performed on the MPLS
packet. MPLS next hops can be chained together to create complex actions.
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Troubleshooting
