Re: [MEXT] [WGLC] draft-ietf-mext-flow-binding-03

[George Tsirtsis <tsirtsis at googlemail.com>]

Hi Yuri, comments inline.

On Fri, Oct 23, 2009 at 1:20 PM, Yuri Ismailov
<yuri.ismailov at ericsson.com> wrote:
> Hi Goerge,
> Thanks for the answers,
> What I did not understand if there will be some clarification text in the draft around "discard" action or all that is obvious and does not require any changes? My comment was that some additional text is needed.
>

GT> I am not yet sure what non-trivial clarification we can provide.
IMO we do not need to provide any further clarifications on this
subject.

> I do not think your clarification about using FID-PRI is quite clear. The reason is that there is no FID for a particular flow within the range There is only a FID for the whole range of port numbers and/or IP addresses.
>

GT> What prevents you from  creating another FID that is specific for that flow?

> Surprized that disclaimer for n-cast about carefull use is in the text and about disclaimer for "discard" you just say "I do not think
> there is anything to say here." Still the question is will there be related text?
>

GT> I think the implication of dropping packets is much clearer than
the implication of n-casting. Dropping packets means the application
to which the packet is sent will not receive the packet...do we really
need to say that? On the other hand, receiving N copies of the same
packet has some implications to TCP....this is also rather obvious for
people that know TCP...but maybe not everyone does.

> Regards
> Yuri
>
>
> -----Original Message-----
> From: George Tsirtsis [mailto:tsirtsis at googlemail.com]
> Sent: Friday, October 23, 2009 11:08 AM
> To: Yuri Ismailov
> Cc: Laganier, Julien; mext at ietf.org
> Subject: Re: [MEXT] [WGLC] draft-ietf-mext-flow-binding-03
>
> Hi Yuri,
>
> Comments inline...
>
> On Tue, Oct 20, 2009 at 8:55 AM, Yuri Ismailov <yuri.ismailov at ericsson.com> wrote:
>> Hi,
>> after re-reading the draft come up with the comment on "Discard"
>> action in "Flow Identification Mobility Option"
>> I suggest either to extend the paragraph in the section 4.2 or add a
>> separate subsection clarifying behavior of MN and HA before and after
>> the "Discard" action was issued by MN.
>>
>> Below are the issues which are proposed to be addressed in the text.
>>
>> 1.The case when installed FID represent ranges of port numbers and IP
>> addresses. If MN decides to discard a particular flow within the range
>> then before that a correspondent FID should be installed in the HA.
>> Otherwise
>> "136 FID not found" will be returned from HA.
>>
>
> GT> If the MN wants to discard a particular flow within a range of
> previously registered flows, it needs to either split the range it two parts, or even better, use a higher FID-PRI for the  discard flow so that packets get matched against it before they get matched against the range.
>
>> 2. Specify the time interval for how long time the "Discard" state
>> will be active in HA. This is necessary because there is no
>> "un-discard" message sent from MN.
>>
>
> GT> Flow bindings share the same lifetime with the BU. There is no
> flow binding-specific lifetime. If an MN wants to remove a flow binding it sends a BU which does not include the corresponding FID.
>
>> 3. Add a disclaimer that for some protocols, like TCP, "Discard"
>> action may lead to hanging up the connection at CN and should be used responsibly.
>>
>
> GT> Discarding packets will drop connections....yes...I do not think
> there is anything to say here.
>
>>
>> Regards
>> Yuri
>>
>>
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>