Configure IRMP Network Optimization

Configuration Condition

Before configuring the IRMP network optimization, first complete the following tasks:

• Configure the IP address of the interface to enable the neighboring nodes to be reachable at the network layer.
• Enable the IRMP protocol.

Configure IRMP Passive Interface

The dynamic routing protocol adopts the passive interface to effectively reduce the network bandwidth consumed by the routing protocol. In the IRMP protocol, the passive interface is configured, which can suppress the IRMP packet receiving and transmitting on the specified interface. For example, if the gigabitethernet 0 is configured as the passive interface, the IRMP does not receive and transmit the packet on this interface even if the network command is used to cover the network segment that the interface locates at.

Table 11-11 Configure the IRMP passive interface

Configure IRMP Stub Mode

Configuring the IRMP stub mode can improve the stability of the IRMP network and reduce the occupied resources. The Stub function is used in the hub and spoke network topology. To enable the Stub function, you only need to configure Stub on the spoke router, but do not need to change the configuration of the hub router. The spoke router specifies the route type to be advertised via the irmp stub command. The hub router does not send the query packets to the Stub neighbor.

Table 11-12 Configure IRMP Stub

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  Modifying the Stub configuration results in the re-connection of all neighbors in the process.

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Configure IRMP Intelligent Query

Configuring the IRMP intelligent query to control the sending of the query packets can reduce the number of the packets exchanged in the network, reducing the occupied resources. If the intelligent query function is enabled, the device does not send the query packets to the neighbor cancelling the route, so as to reduce the number of the query packets and response packets in the network.

Table 11-13 Configure IRMP Stub

Configure IRMP Horizontal Split

The IRMP horizontal split indicates that the route learned by the IRMP from a certain interface will not be advertised out from this interface to avoid forming a loop.

Table 11-14 Configure the IRMP horizontal split

Configure IRMP Timer

1. Configure the keep-alive timer for the IRMP neighbor.

The IRMP Hello packet is used to discover the neighbor and keep it alive by spreading the packet on the network using the periodical and unreliable multicast mode with the multicast address as 224.0.0.10. The default delivery interval for the Hello packet is determined by the network type of the delivery interface. The default delivery interval is 5s on the broadcast and point-to-point interface and is 60s on the NBMA interface.

The hold time indicates the invalid interval of the IRMP neighbor. When a device receives a Hello packet form its neighbor, this packet contains a hold time, which informs the maximum valid time of the neighbor to the device. If the Hello packet is not received from the neighbor when times out, it indicates that the neighbor is not reachable and the neighbor will be removed. By default, the hold time is three times of the hello interval.

Table 11-15 Configure the keep-alive timer for the IRMP neighbor

2. Configure the IRMP route timer.

The IRMP uses the DUAL (Diffusing Update Algorithm) to learn the routing. When the DUAL starts, the Active-timer is enabled. If the response of the queried packets is not received when the timer times out, the neighbors without response will be removed from the neighbor list. The route without response I set to Active and the route is considered as unreachable.

When the IRMP receives the neighbor request, if the local route is learnt from other neighbors, the IRMP will not respond immediately. Instead, enable a hold-down timer and then wait for a period. In the period, if the IRMP does not receive the request packet form the neighbor, it responds the packet to avoid forming the loop.

Table 11-16 Configure the IRMP route timer

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  When configuring the route timer, all neighbors under the process may be reestablished.

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Configure IRMP Static Neighbor

Configure the IRMP static neighbor, where all IRMP packets between neighbors adopt unicast interaction.

To run the IRMP dynamic routing protocol on the NBMA which does not support the broadcast network, such as X.25 and Frame, the static neighbor requires to be configured in pair. Otherwise the neighbor relationship will fail.

Table 11-17 Configure the IRMP static neighbor