KSZ8862-MQL Datasheet, PDF (42/125 Pages) Micrel Semiconductor – 2-Port Ethernet Switch with Non-PCI Interface and Fiber Support

Micrel, Inc.
KSZ8862-16/32MQL
IGMP Support
For Internet Group Management Protocol (IGMP) support in Layer 2, the KSZ8862M provides two components:
“IGMP” Snooping
The KSZ8862M traps IGMP packets and forwards them only to the processor (host port). 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.
IPv6 MLD Snooping
The KSZ8862M traps IPv6 Multicast Listener Discovery (MLD) packets and forwards them only to the processor
(host port). MLD snooping is controlled by SGCR2 [13] (MLD snooping enable) and SGCR2 [12] (MLD option).
Setting SGCR2 [13] causes the KSZ8862M to trap packets that meet all of the following conditions:
• IPv6 multicast packets
• Hop count limit = 1
• IPv6 next header = 1 or 58 (or = 0 with hop-by-hop next header = 1 or 58)
• If SGCR2[12] = 1, IPv6 next header = 43, 44, 50, 51, or 60 (or =0 with hop-by-hop next header = 43, 44,
50, 51, or 60)
Port Mirroring Support
KSZ8862M supports “Port Mirroring” comprehensively as:
“Receive only” mirror on a port
All the packets received on the port are mirrored on the sniffer port. For example, port 1 is programmed to be
“receive sniff” and the host port is programmed to be the “sniffer port”. A packet received on port 1 is destined to
port 2 after the internal lookup. The KSZ8862M forwards the packet to both port 2 and the host port. The
KSZ8862M can optionally even forward “bad” received packets to the “sniffer port”.
“Transmit only” mirror on a port
All the packets transmitted on the port are mirrored on the sniffer port. For example, port 1 is programmed to be
“transmit sniff” and the host port is programmed to be the “sniffer port”. A packet received on port 2 is destined to
port 1 after the internal lookup. The KSZ8862M forwards the packet to both port 1 and the host port.
“Receive and transmit” mirror on two ports
All the packets received on port A and transmitted on port B are mirrored on the sniffer port. To turn on the “AND”
feature, set register SGCR2, bit 8 to “1”. For example, port 1 is programmed to be “receive sniff”, port 2 is
programmed to be “transmit sniff”, and the host port is programmed to be the “sniffer port”. A packet received on
port 1 is destined to port 2 after the internal lookup. The KSZ8862M forwards the packet to both port 2 and the
host port.
Multiple ports can be selected as “receive sniff” or “transmit sniff”. In addition, any port can be selected as the “sniffer
port”. All these per port features can be selected through registers P1CR2, P2CR2, and P3CR2 for ports 1, 2, and the
host port, respectively.
August 2010
42
M9999-081310-3.1