SMSC LAN9312 - Manual (Page 383)

High Performance Two Port 10/100 Managed Ethernet Switch with 32-Bit Non-PCI CPU Interface
Datasheet
SMSC LAN9312 383 Revision 1.4 (08-19-08)
DATASHEET
14.5.3.16 Switch Engine Global Ingress Configuration Register (SWE_GLOBAL_INGRSS_CFG)
This register is used to configure the global ingress rules.
Register #: 1840h Size: 32 bits
BITS DESCRIPTION TYPE DEFAULT
31:14 RESERVED RO -
13 Allow Snoop Echo
When set, snooped packets are allowed to be echoed back to the source
port. When cleared, snooped packets, like other packets, are never sent
back to the source port.
This bit is useful when the snoop port wishes to receive it’s own MLD/IGMP
packets.
R/W 0b
12:10 MLD/IGMP Snoop Port
This field is the port bit map where IPv6 MLD packets and IPv4 IGMP
packets are sent. R/W 0b
9 Use IP
When set, the IPv4 TOS or IPv6 SC field is enabled as a transmit priority
queue choice. R/W 0b
8 Enable MLD Snooping
When set, IPv6 Multicast Listening Discovery packets are snooped and sent
to the MLD/IGMP snoop port. R/W 0b
7 Enable IGMP Snooping
When set, IPv4 IGMP packets are snooped and sent to the MLD/IGMP
snoop port. R/W 0b
6 SWE Counter Test
When this bit is set the Switch Engine counters that normally clear to 0 when
read will be set to 7FFF_FFFCh when read. R/W 0b
5 DA Highest Priority
When this bit is set and the Static bit in the ALR table for the destination
MAC address is set, the transmit priority queue that is selected is taken from
the ALR Priority bits (see the
Switch Engine ALR Read Data 1 Register
(SWE_ALR_RD_DAT_1) ).
R/W 0b
4 Filter Multicast
When this bit is set, packets with a multicast destination address are filtered
if the address is not found in the ALR table. Broadcasts are not included in
this filter. R/W 0b
3 Drop Unknown
When this bit is set, packets with a unicast destination address are filtered
if the address is not found in the ALR table. R/W 0b
2 Use Precedence
When the priority is taken from an IPV4 packet (enabled via the Use IP bit),
this bit selects between precedence bits in the TOS octet or the DIFFSERV
table.
When set, IPv4 packets will use the precedence bits in the TOS octet to
select the transmit priority queue. When cleared, IPv4 packets will use the
DIFFSERV table to select the transmit priority queue.
R/W 1b