Adjust and Optimize the MLD Network

• ---

  The genera query intervals of the devices on the same segment should try to keep consistent.
• The general group query interval should be larger than the maximum response time. Otherwise, the configuration cannot succeed.

  ---

Configure Robustness Factor

The robustness factor is used to prevent the packet loss.

Table 9-6 Configure the robustness factor

• ---

  After configuring the robustness factor, the following parameters also change with the robustness parameters:
  • Group member timeout = Robustness factor * general group query time + maximum response time;
  • Other querier timeout = Robustness factor * general group query time + maximum response time/2;
  • The larger the robustness factor, the larger the MLD group member timeout and other querier timeout. Set the value according to the actuality of the network.

    ---

Configure Maximum Response Time

The general group query packet sent by the querier contains the maximum response time field and the receiver sends the group member relation report within the maximum response interval. If the receiver does not send the group member relation report within the maximum response time, the device regards that the subnet does not have the receiver of the multicast group and deletes the multicast group information immediately.

Table 9-7 Configure the maximum response time

Configure Specified Group Query

After the MLD querier receives the leave packet of one multicast group, send the specified group query packet to query the multicast group on the segment. The sending times of the packet depends on “Specified group query times”. This is to know whether the subnet has the members of the multicast group. If not receiving the member relation report of the multicast group after waiting for “maximum response time”, delete the information of the multicast group.

Table 9-8 Configure the specified group query

Configure Fast Leave

The end segment in the network only connects to one host, which performs the switching action of the multicast group frequently. To reduce the leave delay, you can configure the fast leave of the multicast group on the device.

After configuring the fast leave, the device receives the leave packet of one multicast group and checks whether the multicast group belongs to the fast leave range. If yes, the device does not send the specified group query packet to the segment any more and deletes the information of the multicast group immediately.

Table 9-9 Configure the fast leave