Alcatel-Lucent 7450 Manual page 671

fec-limit
Syntax fec-limit limit [log-only] [threshold percentage]
no fec-limit
Context config>router>ldp>session-parameters>peer
Description
This command configures a limit on the number of FECs which an LSR will accept from a given peer
and add into the LDP label database. The limit applies to the aggregate count of all FEC types
including service FEC. Once the limit is reached, any FEC received will be released back to the peer.
This behavior is different from the per-peer import policy which will still accept the FEC into the
label database but will not resolve it.
When the FEC limit for a peer is reached, the LSR performs the following actions:
Note that if a legitimate FEC is released back to a peer, while the FEC limit was exceeded, the user
must have a means to replay that FEC back to the 7x50 LSR once the condition clears. This is done
automatically if the peer is a 7x50 and supports the LDP overload status TLV (SROS 11.0R5 and
higher). Third party peer implementations would need to support the LDP overload status TLV or
provide a manual command to replay the FEC.
The threshold percent option allows to set a threshold value when a trap and an syslog message are
generated as a warning to the user in addition to when the limit is reached. The default value for the
threshold when not configured is 90%.
The log-only option causes a trap and syslog message to be generated when reaching the threshold
and limit. However, LDP labels are not released back to the peer.
If the user decreases the limit value such that it is lower than the current number of FECs accepted
from the peer, the LDP LSR raises the trap for exceeding the limit. In addition, it will set overload for
peers which signaled support for LDP overload protection capability TLV. However, no existing
resolved FECs from the peer which does not support the overload protection capability TLV should
be de-programmed or released.
A different trap is released when crossing the threshold in the upward direction, when reaching the
FEC limit, and when crossing the threshold in the downward direction. However the same trap will
not be generated more often than 2 minutes apart if the number of FECs oscillates around the
threshold or the FEC limit.
Default no fec-limit
Parameters limit — Specify the aggregate count of FECs of all types which can be accepted from this LDP peer.
7450 ESS MPLS Guide
1. Generates a trap and a syslog message.
2. Generates a LDP notification message with the LSR overload status TLV, for each
LDP FEC type including service FEC, to this peer only if this peer advertised
support for the LSR overload sub-TLV via the LSR Overload Protection Capability
TLV at session initialization.
3. Releases, with LDP Status Code of "No_Label_Resources", any new FEC,
including service FEC, from this peer which exceeds the limit.
Session Parameters Commands
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