Brocade Multi-Service IronWare Multiprotocol Label Switch (MPLS) Configuration Guide (Supporting R05.6.00) - Manual (Page 399)

Multi-Service IronWare Multiprotocol Label Switch (MPLS) Configuration Guide 375
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LDP over RSVP (for transit LSR only)
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Enabling TTL propagation
By default, MPLS traceroute does not display the LSRs the RSVP tunnel is transiting through,
except when the egress router is acting as the egress for both the LDP and the RSVP tunnel. In
other words, the RSVP tunnel is treated as a single hop. The label-propagate-ttl command and the
propagate-ttl command must be enabled in order to display details of the RSVP core. By default,
the propagate-ttl command is enabled. To trace an RSVP path, enable the label-propagate-ttl
command on all Brocade devices along the RSVP path, as shown in the following example.
Brocade(config)# router mpls
Brocade(config-mpls)# policy
Brocade(config-mpls-policy)# label-propagate-ttl
Syntax: [no] label--propagate-ttl
To disable the configuration, enter the [no] form of the command. By default, the
label-propagate-ttl command is turned off. When MPLS traceroute is configured through an RSVP
core, FEC validation for LDP FEC is not preformed at the transit LSR of the RSVP tunnel.
Class of Service (CoS) treatment for LDP over RSVP
The following sections describe COS treatment for LDP over RSVP (transit) for ingress RSVP and
RSVP Penultimate Hop Pop (PHP).
Ingress RSVP
The internal priority of the ingress RSVP is mapped from the incoming LDP label EXP bits. When the
RSVP tunnel has a COS configured, it overrides the internal priority of the ingress RSVP. By default,
the EXP bits in the outgoing RSVP label are mapped from the internal priority. When the qos exp
encoding off command is configured on the outgoing interface, the RSVP label EXP bits are set to
the internal priority of the ingress RSVP. The incoming LDP label EXP bits are preserved in the
outgoing LDP label EXP bits irrespective of whether the qos exp encoding command is turned on or
off on the outgoing interface.
RSVP PHP
The internal priority is mapped from the incoming RSVP label EXP bits. On the egress router of the
RSVP tunnel, the outgoing LDP label EXP bits are set to the incoming LDP label EXP bits. This is
irrespective of whether the qos exp encoding command is turned on or off on the outgoing
interface.
Setting the backup retry interval
By default, RSVP tries to bring up an FRR LSPs backup or detour session every 30 seconds. When
the number of FRR sessions are very large (48K is the maximum number of FRR sessions
supported), RSVP becomes too busy bringing up the backup every 30 seconds for all the LSPs.
Use the backup-retry-time command under the router-mpls policy to change the backup retry
interval.
Brocade(config)# router mpls