Specifications

mpls ldp address-message
MP-197
Cisco IOS Multiprotocol Label Switching Command Reference
January 2010
The ability to map between the IP address and the peer LDP identifier is required so that:
• When the Multiprotocol Label Swithcing (MPLS) forwarding engine (the Label Forwarding
Information Base [LFIB]) asks for labels for a given destination prefix and next hop address, the
LSR can find the label learned (if any) from the next hop. The LSR maintains learned labels in its
label information base (LIB) tagged by the LDP ID of the advertising LSR.
• When the LSR learns a label for destination prefix P from an LDP peer, it can determine if that peer
(known to the LSR by its LDP identifier) is currently the next hop for P.
In principle, an LSR operating in Downstream On Demand (DoD) mode for an LC-ATM interface does
not
need this information for two reasons:
• The LSR should know from the routing table the next hop interface.
• Only one DoD peer exists per LC-ATM interface.
Consequently, Cisco platforms do not normally send Address and Address Withdraw messages to
LC
-ATM peers.
Some LDP implementations might require the information learned in Address and Address Withdraw
me
ssages for LC-ATM. The mpls ldp address-message command is provided to enable interoperability
with implementation vendors that require Address messages for LC-ATM.
Note Cisco platforms always advertise their addresses in Address and Address Withdraw messages for LDP
sessions operating in Downstream Unsolicited label advertisement mode.
Examples The following is an example of the mpls ldp address-message command:
Router(config-if)# mpls ldp address-message
Related Commands Command Description
show mpls interfaces Displays information about one or more or all interfaces that are configured
f
or label switching.