3com S7906E 설치 설명서

 

1-15 

Configure the interface to 
discard any MLD message 
without the Router-Alert option 

Optional 

By default, the device does not 
check MLD messages for the 
Router-Alert option. 

Enable the insertion of the 
Router-Alert option into MLD 
messages 

send-router-alert 

Optional 

By default, MLD messages 
carry the Router-Alert option. 

 

Follow these steps to configure the Router-Alert option on an interface: 

Enter system view 

system-view 

— 

Enter interface view 

interface interface-type 
interface-number 

— 

Configure the interface to 
discard any MLD message 
without the Router-Alert option 

Optional 

By default, the device does not 
check MLD messages for the 
Router-Alert option. 

Enable the insertion of the 
Router-Alert option into MLD 
messages 

mld send-router-alert 

Optional 

By default, MLD messages 
carry the Router-Alert option. 

 

On startup, the MLD querier sends “startup query count” MLD general queries at the “startup query 

interval”, which is 1/4 of the “MLD query interval”.  

The MLD querier periodically sends MLD general queries at the “MLD query interval” to determine 

whether any IPv6 multicast group member exists on the network. You can modify the query interval 

based on the actual condition of the network. 

Upon receiving an MLD done message, the MLD querier sends “last listener query count” MLD 

multicast-address-specific queries at the “MLD last listener query interval”. MLD is robust to 

“robustness variable minus 1” packet losses on a network. Therefore, a greater value of the robustness 

variable makes the MLD querier “more robust”, but results in a longer IPv6 multicast group timeout time.  

Upon receiving an MLD query (general query or multicast-address-specific query) message, a host 

starts a timer for each IPv6 multicast group it has joined. The timer is initialized to a random value in the 

range of 0 to the maximum response delay (the host obtains the maximum response delay from the 

Maximum Response Delay field in the MLD query message it received). When the timer value drops to 

0, the host sends an MLD membership report message to the corresponding IPv6 multicast group. 

Proper setting of the maximum response delay of MLD query messages not only allows hosts to 

respond to MLD query messages quickly, but also avoids bursts of MLD traffic on the network caused 

by reports simultaneously sent by a large number of hosts when corresponding timers expire 

simultaneously.