R0106-HP MSR Router Series Layer 2 - WAN Configuration Guide(V7)

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Command Remarks
4. (Optional.) Set the auto-dial
interval.
dialer timer autodial
autodial-interval
The default setting is 300
seconds.
Configuring dynamic route backup through DDR
The dynamic route backup function creates a dialup connection to a network no valid route on the
primary link is available to the network. This function is mainly used to back up dynamic routes. It can
also back up static routes and direct routes.
To use this function, you must define a network to be monitored. When a backup interface is enabled
with this function, the system monitors the route using the following process:
1. Whenever there is a route update for the monitored network, the system checks whether there is at
least one valid route to the monitored network.
2. If there is at least one valid route with an egress interface that is not enabled with the dynamic route
backup function, the primary link is considered to be up.
3. If there is no valid route, the primary link is considered to be down and unusable, and the DDR
creates a backup link on the backup interface to forward traffic. During this process, the system
periodically checks the primary link status.
4. When the primary link recovers, the backup link can be brought down either immediately or when
the timer expires, depending on the configuration.
Some routing protocols (such as BGP) use the optimal routes by default. Therefore, with BGP employed,
when the secondary link is activated due to a failure of the primary link to the monitored network, the
device will learn a route to the monitored network through BGP. When the primary link recovers, the
device will also learn a route to the monitored network through BGP. However, the route learned for the
primary link might be less optimal than that learned for the secondary link. As a result, all of the following
occur:
• The route learned for the secondary link remains activated.
• Dynamic route monitoring fails.
• The switchover from secondary link to primary link fails.
To address this problem, configure the router to prefer the route learned for the primary link when the
primary and secondary links are both active.
Creating a dynamic route backup group
A dynamic route backup group can define multiple networks to be monitored. When there is no valid
route to any of the monitored networks, DDR creates a dialup link as the backup. When establishing the
backup link, DDR checks the dialer route commands configured on the backup interface. Then, it
establishes the backup link by using the dialer route command first configured for the monitored
networks. Only one backup link is established.
To create a dynamic route backup group:
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p
Command Remarks
1. Enter system view.
system-view N/A