Specifications

snmp-server enable traps mpls ldp
MP-796
Cisco IOS Multiprotocol Label Switching Command Reference
January 2010
The MPLS LDP threshold (mplsLdpFailedInitSessionThresholdExceeded) notification object provides
a warning message that can be sent to an NMS when a local LSR and an adjacent LDP peer attempt to
set up an LDP session between them, but fail to do so after a specified number of attempts. The default
number of attempts is 8. This default value is implemented in Cisco
IOS software and cannot be changed
using either the command line interface (CLI) or an SNMP agent.
In general, Cisco routers support the same features across multiple platforms. Therefore, the most likely
in
compatibility to occur between Cisco LSRs is a mismatch of their respective ATM VPI/VCI label
ranges. For example, if you specify a range of valid labels for an LSR that does not overlap the range of
its adjacent LDP peer, the routers will try eight times to create an LDP session between themselves
before the mplsLdpFailedInitSessionThresholdExceeded notification is generated.
The LSRs whose label ranges do not overlap continue their attempt to create an LDP session between
th
emselves after the eight retry threshold is exceeded. In such cases, the LDP threshold exceeded
notification alerts the network administrator to the existence of a condition in the network that may
warrant attention.
RFC 3036, LDP
Specification, details the incompatibilities that can exist between Cisco routers or other
vendor LSRs in an MPLS network. Among these incompatibilities, for example, are the following:
• Nonoverlapping ATM VPI/VCI ranges (as noted) or nonoverlapping Frame Relay data-link
connection identifier (DLCI) ranges between LSRs attempting to set up an LDP session
• Unsupported label distribution method
• Dissimilar protocol data unit (PDU) sizes
• Dissimilar LDP feature support
The s
nmp-server enable traps mpls ldp command is used with the snmp-server host command. Use
the snmp-server host command to specify which host or hosts receive SNMP notifications. To send
SNMP notifications, you must configure at least one snmp-server host command.
If the pv
-limit keyword is used, a message is generated when the router establishes an LDP session with
its adjacent peer LSR, but the two LSRs have dissimilar path-vector limits.
If the se
ssion-down keyword is used, a session-down message is generated when an LDP session
between the router and its adjacent LDP peer is terminated.
If the se
ssion-up keyword is used, a message is generated when the router establishes an LDP session
with another LDP entity (an adjacent LDP peer in the network).
If the th
reshold keyword is used, a message is generated after eight failed attempts to establish an LDP
session between the router and an LDP peer. The failures can be caused by any type of incompatibility
between the devices.
All four keywords can be used in the same command in any combination.
Note An mplsLdpEntityFailedInitSessionThreshold trap is supported only on an LC-ATM.
Examples In the following example, LDP-specific informs are enabled and will be sent to the host
my
host.cisco.com through use of community string defined as public:
Router(config)# snmp-server enable traps mpls ldp
Router(config)# snmp-server host myhost.cisco.com informs versio
n 2c public mpls-ldp