Adjusting Mld Performance; Configuration Prerequisites; Configuring Mld Message Options - 3Com MSR 50 Series Configuration Manual

1226 C 73: MLD C
HAPTER
Adjusting MLD
Performance
Configuration
Prerequisites
Configuring MLD
Message Options
ONFIGURATION
n
For the configuration tasks described in this section,
Configurations performed in MLD view are globally effective, while
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configurations performed in interface view are effective on the current
interface only.
If the same function or parameter is configured in both PIM view and interface
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view, the configuration performed in interface view is given priority, regardless
of the configuration sequence.
Before adjusting MLD performance, complete the following tasks:
Configure any IPv6 unicast routing protocol so that all devices in the domain
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can be interoperable at the network layer.
Configure basic functions of MLD.
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In addition, prepare the following data:
MLD query interval
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MLD querier robustness variable
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Maximum response delay of MLD general query messages
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MLD last listener query interval
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MLD other querier present interval
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As MLDv1 and MLDv2 involve multicast-address-specific and
multicast-address-and-source-specific queries, and IPv6 multicast groups change
dynamically, a device cannot join all IPv6 multicast groups. Therefore, a router may
receive IPv6 multicast packets addressed to IPv6 multicast groups that have no
members on the local subnet. In this case, the Router-Alert option carried in the
IPv6 multicast packets is useful for the router to make a decision.
For details about the Router-Alert option, refer to RFC 2113.
Depending on whether an MLD message carries the Router-Alert option in the IP
header, the device processes the message differently:
In consideration of compatibility, the device does not check the Router-Alert
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option, that is, it processes all received MLD messages. In this case, the device
passes MLD messages to the upper layer protocol for processing, no matter
whether the MLD messages contains the Router-Alert option.
To enhance the device performance, avoid unnecessary costs, and ensure the
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protocol security, you can configure the device to discard MLD messages
without the Router-Alert option. In this case, when the device receives an MLD
message, it checks it for the Router-Alert option, and discards it if it does not
carry the Router-Alert option.