Brocade Communications Systems IPMC5000PEF manual MLD snooping-enabled queriers and non-queriers

MLD snooping-enabled queriers and non-queriers

Because Brocade does not support MRD, this can lead to stream loss when non-Querier router ports age out on the Querier after the initial Query election. To avoid such stream loss, configure a static router port on the querier on each interface that connects to a non-querier snooping device.

The following details apply to FastIron X Series and ICX 7750 Series devices:

•If MLDv2 is configured on any port of a VLAN, you can check the source information, but because MLD snooping is MAC-based, (S,G) switching is not feasible.

•High CPU utilization occurs when MLD Snooping and PIM6 routing are enabled simultaneously on FastIron X Series devices, and if the ingressing VLAN of the snooping traffic has "router-interface" configuration. With this configuration, IPv6 Multicast data packets received in the snooping VLANs are forwarded to client ports via the hardware; however, copies of these packets are also received and dropped by the CPU.

MLD/PIMv6 SM snooping over Multi-Chasis Trunking is supported on Fastiron X series, ICX 6610, and ICX 7750 devices.

The following details apply to FCX, ICX 6610, ICX 6430, ICX 6450, and ICX 6650 devices:

•If a VLAN is configured for MLDv2, the hardware matches (S G), otherwise it matches (* G).

•When any port of a VLAN is configured for MLDv2, the VLAN matches both source and group (S, G) in hardware switching. If no port is configured for MLDv2, the VLAN matches group only (* G). Matching (S, G) requires more hardware resources than (* G) when there are multiple servers sharing the same group. For example, two data streams from different sources to the same group require two (S, G) entries in MLDv2, compared to only one (* G) in MLD v1.

Use MLD v2 only in a source-specific application. Because each VLAN can be configured for the version independently, some VLANs might match (* G) while others match (S G)

MLD snooping-enabled queriers and non-queriers

An MLD snooping-enabled device can be configured as a querier (active) or non-querier (passive). An MLD querier sends queries; a non-querier listens for MLD queries and forwards them to the entire VLAN. When multiple MLD snooping devices are connected together, and there is no connection to an IPv6 PIM-enabled port, one of the devices should be configured as a querier. If multiple devices are configured as queriers, after multiple devices exchange queries, then all devices except the winner (the device with the lowest address) stop sending queries. Although the system works when multiple devices are configured as queriers, Brocade recommends that only one device, preferably the one with the traffic source, is configured as the querier.

VLANs can also be independently configured as queriers or non-queriers. If a VLAN has a connection to an IPv6 PIM-enabled port on another router, the VLAN should be configured as a non-querier.

Because non-queriers always forward multicast data traffic and MLD messages to router ports which receive MLD queries or IPv6 PIM hellos, Brocade recommends that you configure the devices with the data traffic source (server) as queriers. If a server is attached to a non-querier, the non-querier always forwards traffic to the querier regardless of whether or not there are clients on the querier.

NOTE

In a topology with one or more connected devices, at least one device must be running PIM, or configured as active. Otherwise, no devices can send queries, and traffic cannot be forwarded to clients.

To configure the MLD mode (querier or non-querier) on an MLD snooping-enabled device, refer to Configuring the global MLD mode on page 49. To configure the MLD mode on a VLAN, refer to Configuring the MLD mode for a VLAN on page 52.

FastIron Ethernet Switch IP Multicast Configuration Guide	47
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