Igmp Snooping; Switched Port Analyzer; Oversubscription - Cisco Nexus 2000 Series Manual

Overview
For more information about ACLs, see the Cisco Nexus 7000 Series NX-OS Security Configuration Guide.

IGMP Snooping

IGMP snooping is supported on all host interfaces of the Fabric Extender.
The Fabric Extender and its parent switch support IGMPv2 and IGMPv3 snooping based only on the destination
multicast MAC address. It does not support snooping that is based on the source MAC address or on proxy
reports.
Note For more information about IGMP snooping, see
rfc4541.txt. Also, see the Cisco Nexus 7000 Series NX-OS Multicast Routing Configuration Guide.

Switched Port Analyzer

You can configure the host interfaces on the Fabric Extender as Switched Port Analyzer (SPAN) source ports.
You cannot configure Fabric Extender ports as a SPAN destination. Only one SPAN session is supported for
all the host interfaces on the same Fabric Extender. Ingress source (Rx), egress source (Tx), or both ingress
and egress monitoring are supported.
Note All IP multicast traffic on the VLANs that a Fabric Extender host interface belongs to is captured in the
SPAN session. You cannot separate the traffic by IP multicast group membership.
If you configure ingress monitoring and egress monitoring for host interfaces on the same Fabric Extender,
you might see a packet twice: once as the packet ingresses on an interface with Rx configured, and again
as the packet egresses on an interface with Tx configured.
For more information about SPAN, see the Cisco Nexus 7000 Series NX-OS System Management Configuration
Guide.

Oversubscription

In a switching environment, oversubscription is the practice of connecting multiple devices to the same
interface to optimize port usage. An interface can support a connection that runs at its maximum speed. Because
most interfaces do not run at their maximum speeds, you can take advantage of unused bandwidth by sharing
ports. Oversubscription, which is a function of the available fabric interfaces to active host interfaces, provides
cost-effective scalability and flexibility for Ethernet environments.
The Cisco Nexus 2248TP Fabric Extender has 4 10-Gigabit Ethernet fabric interfaces and 48 100/1000BASE-T
(100-Mb/1-Gigabit) Ethernet host interfaces. When its host interfaces are running in Gigabit Ethernet mode,
it offers the following configurations:
• No oversubscription (40 host interfaces for four fabric interfaces)
• 1.2 to 1 oversubscription (48 host interfaces for four fabric interfaces)
• 4.8 to 1 oversubscription (48 host interfaces for one fabric interface)
Cisco Nexus 2000 Series NX-OS Fabric Extender Software Configuration Guide for Cisco Nexus 7000 Series
http://tools.ietf.org/wg/magma/draft-ietf-magma-snoop/
IGMP Snooping
Switches, Release 5.2
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