The reason is that the client is already using the server and the server is up and running and a REQUEST is the only message that can create a new binding.
While the client COULD return to SOLICIT, that requires more time and processing than sending a REQUEST does. (It gets more complicated too if the client has multiple bindings since it could end up communicating with multiple servers for different bindings which is probably not as desirable.)
<Ravi> In specific case of Client message containing only one IA with a single address, Is it not enough that Client starts with Solicit, instead o Request message ?
Because, incase Client sends Request, then Server would either respond with a Reply containing different Address (than requested) / ignores Client's message, since binding is not available with Server. Instead if Client sends Solicit in response to Server's reply would quicken address acquisition.The client is best to include the addresses it thinks it has in the REQUEST – the server may or may not assign them to the client (it will depend on what is in the REPLY). If the client does not include those addresses, it would be unlikely to get them (as the server has no record of them!) and that may cause problems because now the client may continue to use those addresses until the valid lifetime expires but the server has no record of those addresses being used (which means they could end up being allocated to another client).
This case is really when the server has lost information on the bindings.
- Bernie
From: dhcwg-bounces at ietf.org [mailto:dhcwg-bounces at ietf.org] On Behalf Of ravi kumar
Sent: Monday, November 02, 2009 6:00 AM
To: DHC WG
Subject: [dhcwg] RFC 3315 clarification
I need clarification regarding section 18.1.8 of RFC- 3315 :
<Copy-paste from RFC>
When the client receives a Reply message in response to a Renew or
Rebind message, the client examines each IA independently. For each
IA in the original Renew or Rebind message, the client:
- sends a Request message if the IA contained a Status Code option
with the NoBinding status (and does not send any additional
Renew/Rebind messages)
- sends a Renew/Rebind if the IA is not in the Reply message
- otherwise accepts the information in the IA
What is the intent of client for sending Request, in response to Sever's reply with NOBINDING status code. What addresses do Request message contain ?Incase of Client's message containing only one IA, Is it not enough that Client starts with Solicit, instead o Request message.
Because, incase Client sends Request, then Server would either respond with a Reply containing different Address (than requested) / ignores Client's message, since address is not available with Server. In that case, client finally falls back to Solicit to acquire address.
Instead if Client sends Solicit in response to Server's reply would quicken address acquisition.
Please clarify me in this regard
regards
Ravi