Re: [DNA] Considerations for DNA Schemes with multiple Interface andLayer 2 Technologies

[JinHyeock Choi <jinchoe@samsung.com>]

Dear Eric Njedjou

I think we have confusion about what DNA schemes accomplish. DNA 
schemes aim to detect the identity of currently attached link to verify IP 
configuration. It's closely related, but not identical, to handoff process. 

> Actually the DNA scheme would better not be the same depending on wether i am able to 
> attach to more than one link or not. Effectively, if i am attached for instance to two links at
 > the same time, i may not need to go into the DNA process whenever i receive a hint that 
> one of those links (L2 or L3) is no more valid, if i am able to switch my flows onto the 
> other link without noticeable service interruption (after checking that my IP configuration on 
> that other link is valid).

Even in the above case, DNA scheme is needed. Without DNA process, a host will 
switch flow onto the other link whenever it receive a hint, resulting in undue signaling. 
Also DNA schemes enable a host to check whether its IP configuration on a link is 
valid or not.  
 
> This is why i do not really like the sentence
> "DNA schemes are typically run per interface.  When a host has
>    multiple interfaces, the host separately checks for link changes on
>    each interface."
> As said in the introduction of the dna goals document. I think DNA would better run on 
> an overall basis i.e seeing all of the links (which my Ip layer is capable of for that matter).

I think we have confusion about what DNA schemes accomplish. 

> In the same respect,
> the sentence "Today, a link change necessitates an IP configuration change."
> in the dna goals document introduction let the reader believe that a node would 
> not be having interfaces attached to other links. Because if it is so, then the 
> a configuration that might have been built on the non used link could start being 
> used  without requiring new IP configuration. 

Some IP configuration, such as IP addres, is assigned to an interface. When 
an interface attaches to a new link, its existing IP address is no longer valid. 
Hence the interface needs a new IP address, irrespective of whether the host 
it belongs has other interfaces or not.   

Best Regards

JinHyeock