Huawei Quidway S9300

analyze whether the PW can be used to forward packets. PWE3 ping may fail even though
the MPLS ping is successful.
l PWE3 Tracert
The principle of PWE3 tracert is similar to the principles of MPLS tracert and IP tracert.
The difference lies in that PWE3 tracert uses a PW to forward MPLS echo request packets
to collect node information on the PW. PWE3 tracert may fail even though the MPLS tracert
is successful.
Control Word
The control word (CW) is a four-octet header for encapsulation. The CW is used to send packet
information in the MPLS PSN.
On the PWE3 control plane, a bit indicates whether the CW is presented on the PW.
On the PWE3 data plane, if the CW is supported, a 32-bit CW is added in the header of the
packet to indicate the sequence of the packet. Generally, the disorder of packets occurs only in
load-balancing.
When the LDP PW is used, the negotiation will be successfully only when both the endpoints
of PW support CW, or both do not support CW at the control layer. On the forwarding plane,
the two ends determine whether to support the CW according to the negotiation result.
VCCV-PING
The S9300 supports VCCV ping. That is, you can manually test the connectivity of an LDP PW,
such as a static PW, a dynamic PW, an SH-PW, or an MH-PW on U-PEs.
The VCCV-PING involves the CW mode and MPLS router alert mode:
l In CW mode, you can check the connectivity between two U-PEs.
l In MPLS router alert mode, you can check the connectivity between two U-PEs or from a
U-PE to an S-PE.
PW Template
A PW template is a set of public attributes of PWs. A PW template is shared by multiple PWs.
For scalability, the public attributes of PWs can be added to the PW templates by using
commands. When you create a PW in the interface view, you can use this template.
The S9300 supports the binding between a PW and a PW template. PWs can also be reset.
5.3 Configuring the Attributes of a PW Template
Using a PW template can simplify the configurations of PWs with similar attributes.
5.3.1 Establishing the Configuration Task
5.3.2 Creating a PW Template
5.3.3 Configuring the Attributes for a PW Template
5.3.4 Checking the Configuration
Quidway S9300 Terabit Routing Switch
Configuration Guide - VPN 5 PWE3 Configuration
Issue 03 (2009-08-20) Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd.
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