Alcatel-Lucent 7450 Configuration Manual page 139

label-route-transit
Syntax label-route-transit [all | none]
Context cconfig>router>ttl-propagate
Description
This command configures the TTL propagation for transit packets which are forwarded over a BGP
label route in the Global Routing Table (GRT) context.
For IPv4 and IPv6 packets forwarded using a RFC 3107 label route in the global routing instance,
including 6PE, the all value of the command enables TTL propagation from the IP header into all
labels in the transport label stack. The none value reverts to the default mode which disables TTL
propagation from the IP header to the labels in the transport label stack. This command does not have
a no version.
Note that the TTL of the IP packet is always propagated into the RFC 3107 label itself, and this
command only controls the propagation into the transport labels, for example, labels of the RSVP or
LDP LSP to which the BGP label route resolves and which are pushed on top of the BGP label.
Note that if the BGP peer advertised the implicit-null label value for the BGP label route, the TTL
propagation will not follow the configuration described, but will follow the configuration to which
the BGP label route resolves.
RSVP LSP shortcut:
LDP LSP shortcut:
This feature does not impact packets forwarded over BGP shortcuts. The ingress LER operates in
uniform mode by default and can be changed into pipe mode using the configuration of TTL
propagation for the listed RSVP or LDP LSP shortcut.
Default
none
Parameters none — The TTL of the IP packet is not propagated into the transport label stack.
all — The TTL of the IP packet is propagated into all labels of the transport label stack.
lsr-label-route
Syntax ttl-propagate [all | none]
Context config>router>ttl-propagate
Description This command configures the TTL propagation for transit packets at a router acting as an LSR for a
BGP label route.
When an LSR swaps the BGP label for a ipv4 prefix packet, thus acting as a ABR, ASBR, or data-
path Route-Reflector (RR) in the base routing instance, or swaps the BGP label for a vpn-ipv4 or vpn-
ipv6 prefix packet, thus acting as an inter-AS Option B VPRN ASBR or VPRN data path Route-
Reflector (RR), the all value of this command enables TTL propagation of the decremented TTL of
the swapped BGP label into all outgoing LDP or RSVP transport labels.
Note that when an LSR swaps a label or stitches a label, it always writes the decremented TTL value
into the outgoing swapped or stitched label. What this feature controls is whether this decremented
7450 ESS Router Configuration Guide
• configure router mpls shortcut-transit-ttl-propagate
• configure router ldp shortcut-transit-ttl-propagate
IP Router Configuration
Page 139