Re: [DNA] [Issue X] LinkID v.s. Landmark Prefix

[Syam Madanapalli <syam@samsung.com>]

Erik,



> JinHyeock Choi wrote:
>
>> In linkid scheme, a prefix addition or deletion would not cause an 
>> incorrect decision, whereas there is such a possibility for Landmark/ 
>> CompleteRA. Allow me an example. Assume a link with a router R and host 
>> H. R advertises Prefix1. R1 happens to stop advertising Prefix1 and start 
>> advertising a new prefix Prefix2.
>
> But in this case, when all the prefixes are being removed and replaced 
> with a completely new set of prefixes, there is little if no harm to 
> incorrectly assume a link change (after all, all the addresses need to be 
> reconfigured, etc).
>
> A more realistic example is the one I included in my more recent email 
> today.
>
>> R announces it by sending an RA but H doesn't receive it. Then next time 
>> H receives CompleteRA with
>> Prefix2, it will falsely assume a link change.
>
> Actually not; if will only assume a link change if it receives a link up 
> event notification between the last time it heard a RA with Prefix1 and 
> the first time it heard an RA with Prefix2.

Let us assume the host is rebooting on the same link or changing its
Layer 2 access, even in this case the current linkid scheme does not
make the wrong decision of link change.

Syam

>
>    Erik
>
>> Linkid scheme deal with such a temporary flapping by adopting extra 
>> techniques such as "Linkid Prefix List" or "LEAST_VALID_LIFETIME". I 
>> don't know how Landmark/ CompleteRA can make a correct decision
>> under flapping without such an extra techniques. Thanks in advance for 
>> your kind consideration. Best Regards
>>
>> JinHyeock
>>
>
>
>