Re: [Roll] RPLInstanceID parameter from Source Routing Header is missing in RFC6554

[Dario Tedeschi <[e-mail]>]

Hi Jonathan

Sorry, for late response to your email.

Consider the scenario where a DODAG root node supports two or more RPL 
instances under one prefix. Each instance providing different routing 
objectives (i.e. different objective functions). Potentially, the 
source-route to a destination under one instance can be different to the 
source-route to the same destination under a different instance. For 
example: Instance 1 could have a source-route R-->X-->Y-->D, while 
instance 2 could have a source-route R-->X-->Z-->D. Lets say node Y sent 
a Destination Unreachable ("Error in source-route") back to R, because D 
was unreachable from Y. How would R know which source-route needed 
repair and, consequently, which instance needed a DTSN update?

Regards
Dario

On 01/06/2012 7:46 PM, Jonathan Hui wrote:
>
> I don't understand the need for knowing the RPLInstanceID when 
> handling an ICMP Destination Unreachable error.  The SRH does not 
> follow any RPL Instance, just the IPv6 addresses listed in the SRH. 
>  Receiving an ICMP Destination Unreachable error from a node S simply 
> means that S could not forward to the next IPv6 address in the SRH. 
>  The inability of S to forward to the specified next hop would be true 
> regardless of what RPL Instance the SRH was constructed from.
>
> --
> Jonathan Hui
>
> On Jun 1, 2012, at 7:21 PM, Dario Tedeschi wrote:
>
>> Yes, I noticed this as well. It is unfortunate because as you say, 
>> there is now no way to identify which instance a Error in SRH is for, 
>> and subsequently the root node can't just remove that routing entry 
>> in a specific instance. Instead it must either remove that entry from 
>> all instances or do nothing and wait for the next DAO to update the 
>> entry.
>>
>> Dario
>>
>> On 30/05/2012 1:58 AM, Tecuceanu Andreea-Dana-B10623 wrote:
>>>
>>> Hello,
>>>
>>> I have observed that the RPLInstanceID field from Source Routing 
>>> header (present in  draft-ietf-6man-rpl-routing-header-07) was 
>>> removed in RFC6554.
>>>
>>> Are there particular reasons for this? This field is necessary at 
>>> the DODAG Root when it receives a Destination Unreachable with code 
>>> "Error in Source Routing Header" to identify the instance with the 
>>> problem (only if there are two instances with the same prefix and if 
>>> the node is Root in both of them).
>>>
>>> *Andreea Tecuceanu*
>>> (Freescale Semiconductor)
>>>
>>>
>>>
>>> _______________________________________________
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>>> [e-mail]
>>> https://www.ietf.org/mailman/listinfo/roll
>>
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