Igmp Snooping With Vdcs And Vrfs; Igmp Snooping Across Vpls Domains - Cisco Nexus 7000 Series Configuration Manual

IGMP Snooping with VDCs and VRFs

Previously, the system performs the lookup on a Layer 2 multicast table using the destination IP address rather
than the destination MAC address. However, some applications share a single unicast cluster IP and multicast
cluster MAC address. The system forwards traffic destined to the unicast cluster IP address by the last-hop
router with the shared multicast MAC address. This action can be accomplished by assigning a static multicast
MAC address for the destination IP address for the end host or cluster.
The default lookup mode remains IP, but you can configure the lookup type to MAC address-based. You can
configure the lookup mode globally or per VLAN:
• If the VDC contains ports from only an M-Series module and the global lookup mode is set to IP, VLANs
• If the VDC contains ports from both an M-Series module and an F-Series module and if you change the
IGMP Snooping with VDCs and VRFs
A virtual device context (VDC) is a logical representation of a set of system resources. Within each VDC,
you can define multiple virtual routing and forwarding (VRF) instances. One IGMP process can run per VDC.
The IGMP process supports all VRFs in that VDC and performs the function of IGMP snooping within that
VDC.
You can use the show commands with a VRF argument to provide a context for the information displayed.
The default VRF is used if no VRF argument is supplied.
For information about configuring VDCs, see the Cisco Nexus 7000 Series NX-OS Virtual Device Context
Configuration Guide.
For information about configuring VRFs, see the Cisco Nexus 7000 Series NX-OS Unicast Routing
Configuration Guide.

IGMP Snooping across VPLS Domains

Beginning with Cisco Release 6.2(2) for the Nexus 7000 Series devices, IGMP snooping can be configured
across Virtual Private LAN Service (VPLS) domains. The IGMP Snooping across VPLS Domains feature
enables snooping of the IGMP packets on the pseudowire and on the Layer 2 side of the network for optimal
delivery of the multicast packets.
A pseudowire is a point-to-point connection between pairs of Provider Edge (PE) devices. A pseudowire
emulates services like Ethernet over an underlying core multiprotocol label switching (MPLS) network through
encapsulation into a common MPLS format. A pseudowire allows carriers to converge their services to an
MPLS network by encapsulating services into a common MPLS format.
Cisco Nexus 7000 Series NX-OS Multicast Routing Configuration Guide
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can be set to either one of the two lookup modes. But, if the global lookup mode is set to a MAC address,
the operational lookup mode for all the VLANs changes to MAC-address mode.
lookup mode to a MAC address in any VLAN, the operation lookup mode changes for all of the VLANs
to a MAC-address based. With these modules in the chassis, you have the same lookup mode globally
and for the VLANs. Similarly, if the global lookup mode is MAC-address based, the operational lookup
mode for all VLAN is also MAC-address based.
Note
Changing the lookup mode is disruptive. Multicast forwarding is not optimal
until all multicast entries are programmed with the new lookup mode. Also, when
32 IP addresses are mapped to a single MAC address, you might see suboptimal
forwarding on the device.
Configuring IGMP Snooping