[j-nsp] Enabling Packet Fragmentation in MPLS

[Ali]

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Can someone comment on the following note:
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*"NOTE:* Do not configure the
allow-fragmentation<http://www.juniper.net/techpubs/software/junos/junos82/swconfig82-mpls-apps/html/mpls-summary12.html#1203437>statement
alone. Always configure it in conjunction with the
mtu-signaling<http://www.juniper.net/techpubs/software/junos/junos82/swconfig82-mpls-apps/html/mpls-summary60.html#1204243>statement.
*"*


Why do we need to configure in " allow-fragmentation" conjunction with
"mtu-signaling" under "proctocol mpls path-mtu hierarchy"

Regards