Re: Retransmission of I2 messages

[marcelo bagnulo braun <marcelo@it.uc3m.es>]

Hi,


El 11/12/2006, a las 10:02, Matthijs Mekking escribió:

> Hi,
>
> I have a question about the proto draft. In section 7.12, the draft 
> says
>  "If the initiator does not receive an R2 message after I2_TIMEOUT time
> after sending an I2 message it MAY retransmit the I2 message" and "Thus
> the initiator SHOULD fall back to retransmitting the I1 message when
> there is no R2 received after retransmitting the I2 message
> I2_RETRIES_MAX times."
>
> I am concerned about keywords MAY and SHOULD in section 7.12. If an
> implementation decides not to implement these retransmissions, then
> according to the protocol specification, the fall back to 
> retransmitting
> I1 messages would never occur (because this SHOULD happen after
> I2_RETRIES_MAX retransmissions of I2). If the I2 is not accepted by the
> responder, and no retransmissions are sent, than the context would stay
> in I2-SENT, and is never able to reach ESTABLISHED.
>
> I think the host MAY retransmit I2 messages, but MUST fall back after a
> certain amount of time, to avoid this deadlock situation. The same
> applies for retransmitting I2bis messages.


yes, the idea is that the initiator may retransmit I2 but should 
retransmit I1

i will try to rephrase this more clearly to avoid the deadlock 
situation that you accurely describe

thanks, marcelo


> Furthermore, last week I have sent an e-mail with questions about the
> proto6 draft (http://ops.ietf.org/lists/shim6/msg01738.html). I would 
> be
> very grateful if someone could answer them.
>
> With kind regards,
>
> Matthijs Mekking
> matthijs@NLnetLabs.nl
> NLnetLabs/Radboud University