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Re: [savi] 答复: Binding establishment based on data or control packets?



yaog escribió:
> -----邮件原件-----
> 发件人: marcelo bagnulo braun [mailto:marcelo at it.uc3m.es] 
> 发送时间: 2009年1月22日 18:34
> 收件人: Christian Vogt
> 抄送: SAVI Mailing List; Guang Yao
> 主题: Re: Binding establishment based on data or control packets?
>
> Christian Vogt escribió:
>   
>> Marcelo -
>>
>> In your email below, you identified several situation in which a SAVI
>> device may erroneously discard packets if binding establishment was
>> based on control packets only.  This is correct if you assume that the
>> SAVI device does not react to data packets.  OTOH, the SAVI device may
>> initiate the necessary control packet exchange upon receiving a data
>> packet.  This is what I was assuming to be the case, and what you were
>> assuming not to be the case, I guess.  Hence the misunderstanding.  I
>> think we are on the same page.
>>
>> Having said this, I like the summary of possible solution approaches
>> that you have suggested earlier:  When a SAVI device receives a data
>> packet for which source address it does not have a binding, does it...
>>
>> (1) discard the packet 
>> (2) create a binding for the packet's source address directly
>> (3) initiate a control packet exchange (such as NUD) to verify the
>> packet's source address before creating a binding
>>
>> I agree with you that option (3) does not have a directly apparent
>> advantage.  The only /potential/ advantage that I can think of is that
>> the control packet exchanges initiated in option (3) might be re-usable
>> as a protocol for inter-SAVI-device coordination.  However, this
>> requires more analysis.
>>   
>>     
>
> right
> I have been thinking about this
> Triggering an NSOL upon the reception of a data packet for which there 
> is no binding in the SAVI device could have two potential advantages:
> - first, that can be used to synchronize multiple SAVI devices. this is 
> indeed a benefit
> - second that could allow a victim to know if an attacker is trying to 
> set up a savi state for the victim's address. Now this seems like an 
> advanatage, but after some thought, i don't think it is.
>
> Let's suppose that the savi device sends a RSOL packet upon the 
> reception of a data packet with an unknown source address.
> Suppose the SAVI device receives two replies. What can the SAVI device 
> do with this?
>
> ~Comment Start~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> ~Guang:
> And another comment:
> If you mean two node can get the same address both legally, this just 
> means the nodes and SAVI devices are not well synched.
> ~ Comment End~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
>   

I don't understand what you mean here


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