FBFM2112F897CSLJLS View Datasheet(PDF) - Intel

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Description

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FBFM2112F897CSLJLS

Intel® FM2112 24-Port 10G/1G Ethernet Switch Chip

Intel 

Intel® FM2112 24-Port 10G/1G Ethernet Switch Chip Data Sheet

3.2.3.3

3.2.3.4

3.2.4

• When a frame's destination address is not known by the switch, the frame is

flooded only to the ports in its VLAN member list

VLAN Tunnels

The FM2112 supports two VLAN tunnels, an ad-hoc standard:

• VLAN multicast tunnel

• VLAN unicast tunnel

A VLAN tunnel is a means of suppressing the VLAN checking in some

circumstances. Normally the VLAN membership list is “anded” with the

destination mask to determine the destination port(s) of the traffic and

check for boundary violations. However under some circumstances it is

desirable to make the VLANs more permissive.

A VLAN multicast tunnel suppresses the membership mask check of the

destination address for multicast traffic only.

The VLAN unicast tunnel suppresses the membership mask check for

unicast traffic that is static (the lock bit is set in the MAC address

Table). VLAN unicast tunnel is only supported in shared learning mode.

Double VLAN Tagging

Double VLAN tagging simply adds another layer of IEEE 802.1Q tag

(called “outer tag”) to the 802.1Q tagged packets that enter the

network. The purpose is to expand the VLAN space by tagging the

tagged packets, thus producing a “double-tagged” frame. The

expanded VLAN space allows the service provider to provide certain

services, such as Internet access on specific VLANs for specific

customers, and yet still allows the service provider to provide other

types of services for their other customers on other VLANs.

The FM2000 does support double VLAN tagging by providing the ability

to the user to configure any port to systematically tag all packets

received regardless if they are already VLAN tagged or not. This is

enabled via SYS_PORT_CFG_1: TagAllPackets. The ethernet type used

for the outer tag on the outbound packets depends on whether the

packet was received tagged or untagged. If the packet was received

untagged, then the new tag will be of type 8100 as defined in 802.1Q.

If the packet was tagged, then the new tag is defined in the

MAC_CFG_1:VlanEtherType register.

Network Topology and Spanning Tree Protocol (STP)

The FM2112 is fully compliant with IEEE 802.1D-2003, and supports:

• Spanning Tree Protocol (STP)

• Rapid Spanning Tree Protocol (RSTP)

• Multiple Spanning Tree Protocol (MSTP).

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