Data Sheet

Ethernet Controller I210 —System Manageability
648
When the external MC uses the same IP and MAC address of the OS, the ARP operation should be
coordinated with the Host operating system.
Note: If sharing the MAC and IP with the Host operating system is possible, the I210 provides the
ability to read the stem MAC address, allowing the MC to share the MAC address. There is no
mechanism however provided by the I210 to read the IP address. The Host OS (or an agent
within) and MC must coordinate the sharing of IP addresses.
10.5.3.1 ARP Packet Formats
Table 10-6. ARP Request Packet
Offset # Of bytes Field
Value (In
Hex)
Action
0 6 Destination Address Compare
6 6 Source Address Stored
12 S=(0/4/8) Possible VLAN Tags (single or double) Stored
12 + S D=(0/8) Possible Length + LLC/SNAP Header Stored
12 + S + D 2 Type 0806 Compare
14+ S + D 2 HW Type 0001 Compare
16+ S + D 2 Protocol Type 0800 Compare
18+ S + D 1 Hardware Size 06 Compare
19+ S + D 1 Protocol Address Length 04 Compare
20+ S + D 2 Operation 0001 Compare
22+ S + D 6 Sender HW Address - Stored
28+ S + D 4 Sender IP Address - Stored
32+ S + D 6 Target HW Address - Ignore
38+ S + D 4 Target IP Address ARP IP address Compare
Table 10-7. ARP Response Packet
Offset
# of
bytes
Field Value
0 6 Destination Address ARP Request Source Address
6 6 Source Address Programmed from Flash or MC
12 S=(0/4/8) Possible VLAN Tags (single or double) From ARP Request
12 + S D=(0/8) Possible Length + LLC/SNAP Header From ARP Request
12 + S + D 2 Type 0x0806
14+ S + D 2 HW Type 0x0001
16+ S + D 2 Protocol Type 0x0800
18+ S + D 1 Hardware Size 0x06
19+ S + D 1 Protocol Address Length 0x04
20+ S + D 2 Operation 0x0002
22+ S + D 6 Sender HW Address Programmed from Flash or MC