03-05-2015 11:58 PM - edited 03-07-2019 10:58 PM
Discover - Broadcast
Offer - Unicast
Request - Broadcast
How it is possible that OFFER and ACK sent by
Confused, please clarify.
03-06-2015 07:28 AM
Hi
Firstly, the best way to learn the detail of things like this is fire up WireShark and take a look.
However.. to answer you directly:
A unicast is a packet that is destined to a single address, IP or MAC.
After a client does s DISCOVER, it gets an OFFER from the server.
The server (whether a local server or a relay agent) sends the response with a target IP address of the address it would assign to the client, and the clients L2 MAC address in the L2 header. Therefore it's a unicast, but one based on an assumption of the IP address.
Typically a sending device would ARP for the MAC based on the IP address it wants to reach; in this scenario the cleint wouldn't respond to the ARP (it doesn't have the address, as you say) but the server 'knows better'.
Regards
Aaron
03-10-2015 05:18 AM
@Aaron..
03-10-2015 07:37 AM
No problem.
Please remember to mark questions 'answered' when appropriate to highlight useful content.
Find answers to your questions by entering keywords or phrases in the Search bar above. New here? Use these resources to familiarize yourself with the community: