Data Sheet

Ethernet Controller I210 —Inline Functions
282
7.1.7.1 Filters Details
Table 7-18 lists general details about what packets are processed. In more detail, the packets are
passed through a series of filters to determine if a receive checksum is calculated:
7.1.7.1.1 MAC Address Filter
This filter checks the MAC destination address to be sure it is valid (such as IA match, broadcast,
multicast, etc.). The receive configuration settings determine which MAC addresses are accepted. See
the various receive control configuration registers such as RCTL (RCTL.UPE, RCTL.MPE, RCTL.BAM),
MTA, RAL, and RAH.
7.1.7.1.2 SNAP/VLAN Filter
This filter checks the next headers looking for an IP header. It is capable of decoding Ethernet II,
Ethernet SNAP, and IEEE 802.3ac headers. It skips past any of these intermediate headers and looks
for the IP header. The receive configuration settings determine which next headers are accepted. See
the various receive control configuration registers such as RCTL (RCTL.VFE), VET, and VFTA.
7.1.7.1.3 IPv4 Filter
This filter checks for valid IPv4 headers. The version field is checked for a correct value (4).
IPv6 packet with next header options:
• Hop-by-hop options
• Destinations options (without Home option)
• Destinations options (with Home option)
• Routing (with Segments Left zero)
• Routing (with Segments Left > zero)
•Fragment
No (n/a)
No (n/a)
No (n/a)
No (n/a)
No (n/a)
No (n/a)
Yes
Yes
No
Yes
No
No
Yes
IPv4 tunnels:
• IPv4 packet in an IPv4 tunnel.
• IPv6 packet in an IPv4 tunnel.
Yes (External - as if L3
only)
Yes (IPv4)
No
Yes
1
No
Yes
IPv6 tunnels:
• IPv4 packet in an IPv6 tunnel.
• IPv6 packet in an IPv6 tunnel.
No
No
No
No
No
No
Packet is an IPv4 fragment. Yes No
2
No
Packet is greater than 1518, 1522 or 1526 bytes (LPE=1b)
3
. Yes Yes Yes
Packet has 802.3ac tag. Yes Yes Yes
IPv4 packet has IP options
(IP header is longer than 20 bytes).
Yes Yes Yes
Packet has TCP or UDP options. Yes Yes Yes
IP header’s protocol field contains a protocol number other
than TCP or UDP or SCTP.
Yes No No
1. The IPv6 header portion can include supported extension headers as described in the “IPv6 packet with next header options” row.
2. UDP checksum of first fragment is supported.
3. Depends on number of VLAN tags.
Table 7-18. Supported Receive Checksum Capabilities
Packet Type
Hardware IP
Checksum Calculation
Hardware TCP/
UDP Checksum
Calculation
Hardware SCTP
CRC Calculation