Re: [L3sm] 答复: New Version Notification for draft-wu-l3sm-rfc8049bis-02.txt

[David Ball <[e-mail]>]

Right, but that would still be true if the leaf was called 
svc-flagglestops and there was a flagglestop limit set by the network.  :)

My question is what specific behaviour is the customer requesting or 
expecting by setting svc-mtu to a specific value? Assuming the SP 
accepts the request, there is presumably some resulting difference in 
behaviour for packets shorter than the requested value vs packets longer 
than the requested value?  If so, what is it?  For instance, is it that 
packets with length <= svc-mtu will not be discarded due to their 
length, whereas packets with length > svc-mtu might be?

Right now, the draft does not say anything about the meaning of the 
svc-mtu leaf - one can infer from the name of the leaf that it has 
something to do with packet length, but the details are not specified.  
As Jan said: "For a standard to be useful/interoperable, the system 
behavior needs to be predictable. Undefined behavior needs to become 
defined or outlawed.".  There is no behaviour defined for the svc-mtu 
leaf currently - that is the problem I would like to see addressed.


     David


On 30/08/2017 13:32, Qin Wu wrote:
> It means the requested svc-MTU exceeds MTU limit set by the network, the management system may trigger some MTU discovery mechanism to check this.
>
>
> Sent from HUAWEI AnyOffice
> *发件人： *daviball
> *收件人： *Qin Wu; l3sm;
> *抄送： *stephane.litkowski; ke-oogaki; adrian;
> *主题： *Re: [L3sm] New Version Notification for 
> draft-wu-l3sm-rfc8049bis-02.txt
> *时间： *2017-08-30 19:09:33
>
>
> Hi Qin,
>
> On 28/08/2017 11:13, Qin Wu wrote:
>>
>> [DB3] I completely agree; my point is to provide some information to 
>> the customer about how the service might behave if they request a 
>> particular value for the MTU.
>>
>> [Qin-3]: I prefer to keep as it does, but if you insist, we can 
>> consider to add something like this:
>>
>> “if the requested svc-mtu cannot be fulfilled, the management system 
>> should return a error message indicating the fulfillment is not 
>> possible.  How this SHOULD be communicated by the SP to the customer 
>> via a mechanism that is out of scope for this document.”
>>
>
> This doesn't really address my point.  What does it mean for the 
> requested svc-mtu to be fulfilled?  What behaviour is the customer 
> actually requesting by setting this leaf to a particular value?
>
>
>     David
>
> -- 
> David Ball
> <[e-mail]>

-- 
David Ball
<[e-mail]>