Configure RIPng Network Optimization

Configuration Condition

Before configuring RIPng network optimization, ensure that:

• Configure the interface to enable the IPv6 capability
• Enable the RIPng protocol

Configure RIPng Timers

RIPng does not maintain neighbor relations and does not support route withdrawn; therefore, the protocol provides four configurable timers to control the network convergence speed. The four timers are: route update timer, router timeout timer, route dampening update timer, and route clear timer.

The route timeout time must be at least three times of the route update time. If no route update packet is received within the route timeout time, the route becomes invalid and it enters a dampening cycle. The length of the dampening cycle is determined by the dampening update time. During the cycle, the route will not be cleared. After the dampening cycle is completed, the route enters the clear cycle. During the cycle, the route can be updated. However, if no route update packet is received during the cycle, the route will be deleted.

Table 6-12 Configuring RIPng timers

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  In the same RIPng routing domain, the timer configurations on all the devices must be the same to prevent network flapping.

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Configure RIPng Split Horizon and Toxicity Reverse of RIP

Split horizon and toxicity reverse are mechanisms that are used to prevent route loops.

1. Configure split horizon.

RIPng does not advertise routes that it has learnt from an interface to the interface, preventing routing loops.

Table 6-13 Configure RIPng split horizon

2. Configure toxicity reverse.

RIPng advertises the routes that have been learnt from an interface to the interface, but the route metric is the maximum number of hops 16, preventing routing loops.

Table 6-14 Configure RIPng toxicity reverse

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  The split horizon and toxicity reverse functions are valid only for the learnt routes, direct routes of the RIPng interface, and the redistributed direct and static routes.
• The split horizon function and the toxicity reversion function cannot be used at the same time.

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Configure a Static RIPng Neighbor

RIPng does not maintain neighbor relations, so it does not have the concept of neighbor. Here the neighbor refers to the neighbor RIPng routing device. After a static RIPng neighbor is specified, RIPng sends RIPng packets to the neighbor in unicast mode. The configuration is applied to a network that does not support broadcast or multicast, such as point-to-point links. If the configuration is applied to a broadcast or multicast network, it may cause repeated RIPng packets in the network.

Table 6-15 Configure a static RIPng neighbor

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  RIPng advertises routes only to the interfaces that it covers, and ipv6 rip passive cannot prevent an interface from sending packets to its static neighbor.

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Configure a Passive RIPng Interface

To decrease the network bandwidth consumed by the routing protocol, the dynamic routing protocol uses the passive interface function. RIPng receives only route update packets on a passive interface, and it does not send route update packets on the passive interface. In a low-speed network with small bandwidth, the passive interface function and the neighbor function cooperate to effectively reduce interactions of RIPng routes.

Table 6-16 Configure a passive RIPng interface

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  ipv6 rip passive does not restrain an interface from sending unicast route updates to its neighbor devices. When being used with the neighbor command, ipv6 rip passive does not restrain an interface from sending unicast route updates to its neighbor devices. This application mode can control a router so that it sends route updates only to some neighbor devices in unicast mode instead of sending route updates to all neighbor devices in multicast mode.

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