KSZ8895 INFINEON [Infineon Technologies AG], KSZ8895 Datasheet - Page 46

• Manufacturer Part Number: KSZ8895
• Description: Integrated 5-Port 10/100 Managed Ethernet Switch with MII/RMII interface
• Manufacturer: INFINEON [Infineon Technologies AG]

Micrel, Inc.
IGMP Support
For Internet Group Management Protocol (IGMP) support in Layer 2, the KSZ8895MQ/RQ/FMQ provides two
components:
IGMP Snooping
The KSZ8895MQ/RQ/FMQ traps IGMP packets and forwards them only to the processor (Port 5 SW5-MII). The
IGMP packets are identified as IP packets (either Ethernet IP packets, or IEEE 802.3 SNAP IP packets) with IP
version = 0x4 and protocol version number = 0x2.
Multicast Address Insertion in the Static MAC Table
Once the multicast address is programmed in the Static MAC Table, the multicast session is trimmed to the
subscribed ports, instead of broadcasting to all ports.
To enable IGMP support, set register 5 bit [6] to ‘1’. Also, “Tail tag mode” needs to be enabled, so that the processor
knows which port the IGMP packet was received on. Enable “Tail tag mode” by setting Register 12 bit 0.
Port Mirroring Support
The KSZ8895MQ/RQ/FMQ supports “port mirror” comprehensively as:
Multiple ports can be selected to be “rx sniffed” or “tx sniffed.” And any port can be selected to be the “sniffer port.”
All these per port features can be selected through Register 17.
VLAN Support
The KSZ8895MQ/RQ/FMQ supports 128 active VLANs and 4096 possible VIDs specified in IEEE 802.1q.
KSZ8895MQ/RQ/FMQ provides a 128-entry VLAN table, which correspond to 4096 possible VIDs and converts to
FID (7 bits) for address look-up max 128 active VLANs. If a non-tagged or null-VID-tagged packet is received, then
the ingress port VID is used for look-up when 802.1q is enabled by the global register 5 control 3 bit 7. In the VLAN
mode, the look-up process starts from VLAN table look-up to determine whether the VID is valid. If the VID is not
valid, the packet will then be dropped and its address will not be learned. If the VID is valid, FID is retrieved for
further look-up by the static MAC table or dynamic MAC table. FID+DA is used to determine the destination port. The
followed table describles the difference actions at different situstions of DA and FID+DA in the static MAC table and
dynamic MAC table after the VLAN table finish a look-up action. FID+SA is used for learning purposes. The followed
table also describles how to learning in the dynamic MAC table when VLAN table has done a look-up and the static
MAC table without a valid entry.
January 2011
“Receive Only” mirror on a port
“Transmit Only” mirror on a port
“Receive and Transmit” mirror on two ports.
All the packets received on the port will be mirrored on the sniffer port. For example, Port 1 is programmed to be
“rx sniff,” and Port 5 is programmed to be the “sniffer port.” A packet, received on Port 1, is destined to Port 4 after
the internal look-up. The KSZ8895MQ/RQ/FMQ will forward the packet to both Port 4 and Port 5.
KSZ8895MQ/RQ/FMQ can optionally forward even “bad” received packets to Port 5.
All the packets transmitted on the port will be mirrored on the sniffer port. For example, Port 1 is programmed to
be “tx sniff,” and Port 5 is programmed to be the “sniffer port.” A packet, received on any of the ports, is destined
to Port 1 after the internal look-up. The KSZ8895MQ/RQ/FMQ will forward the packet to both Ports 1 and 5.
All the packets received on port A AND transmitted on port B will be mirrored on the sniffer port. To turn on the
“AND” feature, set Register 5 bit 0 to 1. For example, Port 1 is programmed to be “rx sniff,” Port 2 is programmed
to be “transmit sniff,” and Port 5 is programmed to be the “sniffer port.” A packet, received on Port 1, is destined to
Port 4 after the internal look-up. The KSZ8895MQ/RQ/FMQ will forward the packet to Port 4 only, since it does not
meet the “AND” condition. A packet, received on Port 1, is destined to Port 2 after the internal look-up. The
KSZ8895MQ/RQ/FMQ will forward the packet to both Port 2 and Port 5.
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KSZ8895MQ/RQ/FMQ
M9999-012011-1.2