Configuring A Local Ldp Session; Establishing The Configuration Task - Huawei AR1200 Series Configuration Manual - Mpls

Huawei AR1200 Series Enterprise Routers
Configuration Guide - MPLS
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2.3 Configuring a Local LDP Session

A local LDP session must be established between each pair of directly connected LSRs on an
LSP before the LSP is established.

2.3.1 Establishing the Configuration Task

Before configuring a local LDP session, familiarize yourself with the applicable environment,
complete the pre-configuration tasks, and obtain the data required for the configuration. This
will help you complete the configuration task quickly and accurately.
Applicable Environment
A local LDP session must be created between each pair of directly connected LSRs before an
LSP is established. LDP distributes and swaps label along an LSP.
Pre-configuration Tasks
Before configuring a local LDP session, complete the following task:
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Data Preparation
To configure a local LDP session, you need the following data.
Issue 01 (2011-12-30)
– LDP MD5: A typical MD5 application is to calculate a message digest to prevent
message spoofing. The MD5 message digest is a unique result calculated using an
irreversible character string conversion. If a message is modified during transmission,
a different digest is generated. After the message arrives at the receiving end, the
receiving end can detect the modification after comparing the received digest with a
pre-computed digest.
– LDP keychain: Keychain, an enhanced encryption algorithm similar to MD5, calculates
a message digest for an LDP message to prevent the message from being modified.
– LDP GTSM: The GTSM checks TTL values to defend against attacks. The GTSM can
be configured to check whether or not the TTL value in the IP header is within a specified
range, protecting the nodes against attacks and improving system security.
LDP GR
Graceful restart (GR) is a key technique for high availability (HA). GR is used to protect
traffic during active main board (AMB)/standby main board (SMB) switchovers and
upgrade. LDP GR prevents the system from resetting an interface board when an AMB/
SMB switchover is performed. This helps retain LDP LSP information on the data plane,
ensures uninterrupted LSP forwarding, and minimizes adverse impact on MPLS packet
forwarding.
NOTE
The AR1200 can function as only the Helper router, but cannot function as the Restarter router.
Configuring static routes or an IGP to ensure reachable routes between LSRs
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