Re: [Dots] Mirja Kühlewind's Discuss on draft-ietf-dots-requirements-18: (with DISCUSS and COMMENT)

["Mirja Kuehlewind (IETF)" <[e-mail]>]

Hi,

please see below.

> Am 21.02.2019 um 12:18 schrieb Teague, Nik <[e-mail]>:
> 
> Hi,
> 
> 
> On 21 Feb 2019, at 10:58, Mirja Kuehlewind (IETF) <[e-mail]> wrote:
> 
>>>> 3) In SIG-006 you say:
>>>> "      Due to the higher likelihood of packet loss during a DDoS attack,
>>>>    DOTS servers MUST regularly send mitigation status to authorized
>>>>    DOTS clients which have requested and been granted mitigation,
>>>>    regardless of client requests for mitigation status."
>>>> 
>>>> Please note that this is only true if a not-reliable transport is used. If a
>>>> reliable transport is used, data is received at the application level without
>>>> loss (but maybe some delay) or the connection is terminated (if loss is too
>>>> high to retransmit successfully).
>>>> 
>>> 
>>> [Med] The requirement as worded is OK. 
>> 
>> I disagree, because as I said if a reliable transport is used this is not true. Maybe you can adapt this sentence slightly to clarify that you probably had a scenario in mind where an unreliable transport is used
> 
> The key part here is ‘packet’ vs ‘data’ - packets will be lost on congested links regardless of data integrity.  This may degrade connection re-establishment with tcp and cause data loss in an unreliable transport.

Yes, packet loss also occurs also with reliable transports and might lead to connection failure. However, I don’t this how this requirement is derived from that effect. If I use a reliable transport and my connection does not fail, I can be sure that the mitigation status information have been received correctly, so why do I need to re-send frequently then?

Mirja