For this case, assume that the requesting host is on class C network 192.1.127.0, has address 192.1.127.19, that there is a gateway at 192.1.127.50, and that on network an 3-bit subnet field is in use (01011000), that is, the address mask is 255.255.255.88.
The host sends the ICMP request to 255.255.255.255:
Source address: 192.1.127.19
Destination address: 255.255.255.255
Protocol: ICMP = 1
Type: Address Mask Request = AM1
Code: 0
Mask: 0
The gateway can then respond directly to the requesting host.
Source address: 192.1.127.50
Destination address: 192.1.127.19
Protocol: ICMP = 1
Type: Address Mask Reply = AM2
Code: 0
Mask: 255.255.255.88.
In the diskless workstation case the host sends:
Source address: 0.0.0.0
Destination address: 255.255.255.255
Protocol: ICMP = 1
Type: Address Mask Request = AM1
Code: 0
Mask: 0
192.1.127.50 will hear the datagram, and should respond with this
datagram:
Source address: 192.1.127.50
Destination address: 255.255.255.255
Protocol: ICMP = 1
Type: Address Mask Reply = AM2
Code: 0
Mask: 255.255.255.88.
If broadcasting is not allowed 192.1.127.19 sends:
Source address: 192.1.127.19
Destination address: 192.1.127.50
Protocol: ICMP = 1
Type: Address Mask Request = AM1
Code: 0
Mask: 0
192.1.127.50 should respond exactly as in the previous case.
Source address: 192.1.127.50
Destination address: 192.1.127.19
Protocol: ICMP = 1
Type: Address Mask Reply = AM2
Code: 0
Mask: 255.255.255.88