Data Sheet

Power Management—Ethernet Controller I210
173
5.7 Protocol Offload (Proxying)
In order to avoid spurious wake-up events and reduce system power consumption when the device is in
D3 low power state and system is in S3 or S4 low power states, the I210 supports protocol offload
(proxying) of:
1. A single IPv4 Address Resolution Protocol (ARP) request.
— Responds to IPv4 address resolution request with the host MAC (L2) address (as defined in RFC
826).
2. Two IPv6 Neighbor Solicitation (NS) requests, where each NS protocol offload request includes two
IPv6 addresses, for a total of four possible IPv6 addresses.
— IPv6 NS requests with the host MAC (L2) address (as defined in RFC 4861).
3. When NS protocol offload is enabled, the I210 supports up to two IPv6 Multicast-Address-Specific
Multicast Listener Discovery (MLD) queries (either MLDv1 or MLDv2). In addition, the I210 also
responds to general MLD queries, used to learn which IPv6 multicast addresses have listeners on an
attached link.
— MLD protocol offload is supported when NS protocol offload is enabled so that IPv6 routers
discover the presence of multicast listeners (that is, nodes wanting to receive multicast
packets), for packets with the IPv6 NS Solicited-node Multicast Address and continue
forwarding these NS requests on the link.
— MLD protocol offload is supported for either MLD Multicast Listener Query packets or MLD
Multicast Address and Source Specific Query packets that check for IPv6 multicast listeners
with the Solicited-node Multicast Address placed in the IPv6 destination address field of the
IPv6 NS packets that are off-loaded by the I210.
Table 5-6. ARP Packet Structure and Processing
Offset # of bytes Field Value Action Comment
0 6 Destination Address Compare
MAC header – processed by main
address filter.
6 6 Source Address Skip
12 S=(0/4/8)
Possible VLAN Tags (single or
double)
Compare on
internal VLAN
only
Processed by main address filter.
12 + S D=(0/8)
Possible Length + LLC/SNAP
Header
Skip
12 + S + D 2 Ethernet Type 0x0806 Compare ARP
14 + S + D 2 HW Type 0x0001 Compare
16 + S + D 2 Protocol Type 0x0800 Compare
18 + S + D 1 Hardware Size 0x06 Compare
19 + S + D 1 Protocol Address Length 0x04 Compare
20 + S + D 2 Operation 0x0001 Compare
22 + S + D 6 Sender HW Address - Ignore
28 + S + D 4 Sender IP Address - Ignore
32 + S + D 6 Target HW Address - Ignore
38 + S + D 4 Target IP Address IP4AT Compare
Compare if the Directed ARP bit is
set to 1b.
May match any of four values in
IP4AT.