9.2.3 (Optional) Configuring CC and CV for Sections on an LSP
Context
CC and CV are two different MPLS-TP OAM functions. CC checks the loss of continuity (LOC)
defects between two MEPs in a MEG. CV is used to detect consistency of configurations on two
MEPs in a MEG or in different MEGs. The purpose of CC greatly differs from that of CV. The
details are as follows:
l
CC for sections in an LSP is a pro-active OAM operation. It detects connectivity between
the two MEPs in a MEG. A MEP sends CCMs to its RMEP at intervals. If the RMEP does
not receive CCMs within a period 3.5 times the specified interval, it considers that the
connectivity between the two MEPs is faulty and will report an alarm and enter the Down
state. After receiving a CCM from the MEP, the RMEP will clear the alarm and exit from
the Down state.
l
CV for sections on an LSP is also a pro-active OAM operation. It enables a MEP to report
alarms when the EMP receives unexpected packets. For example, if a CV-enabled device
receives a packet from a section and finds that this packet is mistakenly transmitted by the
section, the device will report an alarm indicating a forwarding error.
Transport networks have strict requirements on data forwarding correctness. In addition,
MPLS-TP requires that the data plane be able to work without IP support, which means
that packet forwarding is based on label switching only. Therefore, the correctness of label-
based forwarding must be guaranteed.
In real world situations, CC and CV are usually used together. Therefore, these two functions
are integrated on the NE80E/40E. Perform the following steps on the MEP and RMEP:
Procedure
Step 1
Run:
system-view
The system view is displayed.
Step 2
Run:
mpls-tp meg
meg-name
The MEG view is displayed.
Step 3
(Optional) Run either of the following commands:
NOTE
Ensure that the same CCM transmission interval is set on the MEP and RMEP; otherwise, an alarm will be
generated.
l
To configure the interval between CCM transmissions, run the
cc interval
interval-value
command.
CCM transmission intervals and their application scenarios are as follows:
–
3.3 ms: 300 frames are sent per second. This interval is recommended in protection
switching.
–
10 ms: 100 frames are sent per second.
–
100 ms: 10 frames are sent per second. This interval is recommended in performance
monitoring.
HUAWEI NetEngine80E/40E Router
Configuration Guide - Reliability
9 MPLS-TP OAM Configuration
Issue 02 (2014-09-30)
Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd.
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